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id	title	slug	type	status	content	archieml	archieml_update_statistics	published_at	updated_at	gdocSuccessorId	authors	excerpt	created_at_in_wordpress	updated_at_in_wordpress	featured_image	formattingOptions	markdown	wpApiSnapshot
35067	Our history is a battle against the microbes: we lost terribly before science, public health, and vaccines allowed us to protect ourselves	microbes-battle-science-vaccines	post	publish	<!-- wp:html --> <div class="blog-info"> <p>updated version: 21 July 2020</p> <p>Our World in Data presents the data and research to make progress against the world’s largest problems.<br>This blog post draws on data and research discussed in our entries on <strong><a href="https://ourworldindata.org/vaccination" target="_blank" rel="noopener noreferrer">vaccination</a></strong> and the <strong><a href="https://ourworldindata.org/coronavirus" target="_blank" rel="noopener noreferrer">coronavirus pandemic</a></strong>.</p> <p>For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.</p> </div> <!-- /wp:html --> <!-- wp:paragraph --> <p>Humanity’s history is a continuous battle between us and the microbes.{ref}An excellent book on the topic is: Dorothy H. Crawford  (2009) – Deadly Companions: How microbes shaped our history.{/ref} For most of our history we were on the losing side.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>It wasn’t even close. We were losing very decisively. Billions of children died from infectious diseases. They were the main reason why child mortality was so high: No matter where or when they were born, around half died as children. We looked at the evidence of child mortality in pre-modern times <a href="https://ourworldindata.org/child-mortality-in-the-past">here</a>. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The recurring epidemics of influenza, measles, cholera, diphtheria, the bubonic plague, and smallpox also killed large parts of the adult population. Within just a few years the Black Death killed half of Europe’s population.{ref}See the time-series of the English population <a href="https://ourworldindata.org/grapher/population-of-england-millennium">here</a>.<br>Mortality was similarly high, or even higher, in other parts of Europe.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In his history of the Black Death Ole Jørgen Benedictow suggests that 60% of the population of Europe died in that pandemic. [See Benedictow (2004) – The Black Death 1346–1353: The Complete History.]{/ref} The epidemics – especially of smallpox, but also measles, typhus and other diseases – that the colonialists brought from Europe with them to the Americas often killed an even larger share of the population.{ref}See Noble David Cook (1998) – Born to Die: Disease and New World Conquest, 1492-1650. Cambridge University Press.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The world today is obviously very different. Infectious diseases are the cause of <a href="https://ourworldindata.org/causes-of-death#causes-of-death-by-category">fewer than 1-in-6 deaths</a>, and as the world made progress against the microbes our lives became much longer. The global average life expectancy is now 73 years after life expectancy <a href="https://ourworldindata.org/life-expectancy-globally">doubled in every world region</a>.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":5} --> <h5>Until recently no one knew where diseases came from</h5> <!-- /wp:heading --> <!-- wp:paragraph --> <p>How is it possible that for millennia we were losing the battle against the microbes so awfully and then turned things around in the span of just a few generations?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Science is the foundation for our success. 150 years ago nobody knew where diseases came from. Or more precisely, people thought they knew, but they were wrong. The widely accepted idea at the time was the ‘Miasma’ theory of disease. Miasma, the theory held, was a form of "bad air" that causes disease. The word <em>malaria</em> is testament to the idea that ‘mal aria’ – ‘bad air’ in medieval Italian – is the cause of the disease.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Thanks to the work of a number of doctors and chemists in the second half of the 19th century humanity learned that not noxious air, but specific germs cause infectious diseases. The <em>germ theory of disease</em> was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines. </p> <!-- /wp:paragraph --> <!-- wp:heading {"level":5} --> <h5>Vaccines get your immune system ready for the battle</h5> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease. “The fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,” as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here <a href="https://moxforum.co.uk/archive/">moxforum.co.uk/archive/</a>{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body’s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":5} --> <h5>Public health: You are only safe if everyone else is safe</h5> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>As is so often the case in development <a href="https://ourworldindata.org/global-inequality-of-opportunity">you cannot achieve progress by yourself</a>. Your progress towards a healthier life depends on everyone else’s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe – as early as the 17th century – was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. <em>The Economic History Review</em>, <em>73</em>(3), E1–E19. <a href="https://doi.org/10.1111/ehr.13019">https://doi.org/10.1111/ehr.13019</a>{/ref} </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an <a href="https://rootsofprogress.org/draining-the-swamp">excellent overview</a> of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now – in the COVID-19 pandemic – that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this <a href="https://ourworldindata.org/identify-covid-exemplars">here</a>). </p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4>Infectious diseases before and after the vaccine was introduced</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>How effective were these training sessions against infectious diseases?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the <strong>three charts </strong>I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>Smallpox</strong> was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) – Smallpox: The Death of a Disease - The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref} Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very <a href="https://ourworldindata.org/smallpox#vaccine-against-smallpox">first vaccine ever</a>.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In England in the mid‐eighteenth century it was probably the leading cause of death.{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality†. <em>The Economic History Review</em>, <em>73</em>(3), E1–E19. <a href="https://doi.org/10.1111/ehr.13019">https://doi.org/10.1111/ehr.13019</a>{/ref} But in the following century – as the vaccine reached more people and improved over time – it became rarer and rarer as a cause of death.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved <a href="https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication">the lives</a> of around 150 to 200 million people since.</p> <!-- /wp:paragraph --> <!-- wp:owid/prominent-link {"title":"Our research and data on smallpox","linkUrl":"https://ourworldindata.org/smallpox","mediaId":19619,"mediaUrl":"https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country.png","mediaAlt":"","className":"is-style-thin"} --> <!-- wp:paragraph --> <p>We eradicated one of the worst infectious diseases globally.</p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --> <!-- wp:separator --> <hr class="wp-block-separator"/> <!-- /wp:separator --> <!-- wp:paragraph --> <p>The history of <strong>polio</strong> is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient’s breathing muscles. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients’ only chance to survive was to be <a href="https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung">confined to a large, mechanical breathing apparatus</a>: the so-called ‘iron lungs’. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as “more than a scientific achievement” according to Salk’s biographer Richard Carter.{ref}“Richard Carter (1966) – Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, “was a folk victory, an occasion for pride and jubilation… people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,… took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.”</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s <a href="https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region">there were</a> between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at <a href="http://polioeradication.org/polio-today/polio-now/this-week">polioeradication.org/polio-today/polio-now/this-week</a>  {/ref}</p> <!-- /wp:paragraph --> <!-- wp:owid/prominent-link {"title":"Our research and data on polio.","linkUrl":"https://ourworldindata.org/polio","mediaId":14021,"mediaUrl":"https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region.png","mediaAlt":"","className":"is-style-thin"} --> <!-- wp:paragraph --> <p>With the help of the vaccine we might be able to eradicate polio globally.</p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --> <!-- wp:separator --> <hr class="wp-block-separator"/> <!-- /wp:separator --> <!-- wp:paragraph --> <p><strong>Measles</strong> too was a major killer for many centuries. The WHO reports: “Before the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2–3 years and measles caused an estimated 2.6 million deaths each year.”{ref}WHO (2019) – Measles, Key Facts. 5 December 2019. Online here <a href="https://www.who.int/en/news-room/fact-sheets/detail/measles">https://www.who.int/en/news-room/fact-sheets/detail/measles</a> {/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) – the average number of secondary cases arising from each case – range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., & Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. <em>The Lancet Infectious Diseases</em>, <em>17</em>(12), e420–e428.<a href="https://doi.org/10.1016/S1473-3099(17)30307-9"> https://doi.org/10.1016/S1473-3099(17)30307-9</a>{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Globally we have also made a lot of progress. Today, 85% of one-year olds <a href="https://ourworldindata.org/grapher/share-of-children-vaccinated-against-measles?tab=chart&time=1983..2017&country=~OWID_WRL">receive</a> the measles vaccine and the number of deaths has fallen from 2.6 million <a href="https://ourworldindata.org/grapher/deaths-due-to-measles-gbd">to 83,000 in the latest data</a>. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox.<br>See <a href="https://en.wikipedia.org/wiki/Vaccine-preventable_diseases">https://en.wikipedia.org/wiki/Vaccine-preventable_diseases</a> and <a href="https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/">https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/</a>{/ref}<br>I selected these three diseases because they protect us from <em>particularly</em> terrible diseases. And the vaccines for polio and measles stand out because even the very early stage prototypes were very efficacious; the efficacy of many other vaccines increased slowly over time as researchers made adjustments that improved them.</p> <!-- /wp:paragraph --> <!-- wp:image {"id":39984,"sizeSlug":"full","linkDestination":"none"} --> <figure class="wp-block-image size-full"><img src="https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths.jpg" alt="" class="wp-image-39984"/></figure> <!-- /wp:image --> <!-- wp:heading {"level":4} --> <h4>Science is our best strategy now</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Some of the best training you ever received were the vaccines you were given in your very early childhood. Without even realizing it, you learned how to battle the pathogens that ravaged the lives of your ancestors for many millennia.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>When humanity achieves very substantial progress it can become difficult to understand what the problems were that we made progress against. This is also the case for vaccine-preventable diseases. Infectious diseases that once disfigured, pained, paralyzed, and killed many of our ancestors have disappeared so far from our lives and memories that some today can afford the luxury of disregarding or even avoiding vaccination.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Today as we face the COVID-19 pandemic, it is the first time for many of us that we experience for one infectious disease what our ancestors experienced for a whole range of them. Just as they were without protection against the diseases discussed previously, we are now facing a pathogen that we have no treatment for and no protection from. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>And now, just as back then, our best hope is science. The responses from <a href="https://ourworldindata.org/covid-exemplar-south-korea">South Korea</a>, <a href="https://ourworldindata.org/covid-exemplar-vietnam">Vietnam</a>, and <a href="https://ourworldindata.org/covid-exemplar-germany">Germany</a> show that it is possible to fight the disease successfully, but to end the suffering that COVID-19 causes our best hope is a vaccine against the virus. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We were never better equipped to battle a virus. The genome was sequenced within two weeks and since then scientists around the world have been <a href="https://www.bloomberg.com/news/features/2020-07-15/oxford-s-covid-19-vaccine-is-the-coronavirus-front-runner">working tirelessly</a> to develop the vaccine that brings the pandemic to an end. The <a href="https://www.ox.ac.uk/news/2020-07-20-new-study-reveals-oxford-coronavirus-vaccine-produces-strong-immune-response">early results</a> from the vaccine developed here at the University of Oxford are promising.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Our best strategy in the age-old fight against the germs is our collaborative, data-based effort to study the world around us and within us. Our best strategy is science.</p> <!-- /wp:paragraph --> <!-- wp:separator --> <hr class="wp-block-separator"/> <!-- /wp:separator --> <!-- wp:paragraph --> <p>…<em>continue reading on Our World in Data:</em></p> <!-- /wp:paragraph --> <!-- wp:owid/prominent-link {"title":"Our data and research on the COVID-19 pandemic","linkUrl":"https://ourworldindata.org/coronavirus","mediaId":34463,"mediaUrl":"https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18.png","mediaAlt":"","className":"is-style-thin"} --> <!-- wp:paragraph --> <p>We currently focus our efforts on the data and research on the COVID-19 pandemic. What does the latest data say? How can we win the battle against COVID-19?</p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph -->	{ "id": "wp-35067", "slug": "microbes-battle-science-vaccines", "content": { "toc": [], "body": [ { "type": "text", "value": [ { "text": "updated version: 21 July 2020", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Our World in Data presents the data and research to make progress against the world\u2019s largest problems.", "spanType": "span-simple-text" }, { "spanType": "span-newline" }, { "text": "This blog post draws on data and research discussed in our entries on ", "spanType": "span-simple-text" }, { "children": [ { "url": "https://ourworldindata.org/vaccination", "children": [ { "text": "vaccination", "spanType": "span-simple-text" } ], "spanType": "span-link" } ], "spanType": "span-bold" }, { "text": " and the ", "spanType": "span-simple-text" }, { "children": [ { "url": "https://ourworldindata.org/coronavirus", "children": [ { "text": "coronavirus pandemic", "spanType": "span-simple-text" } ], "spanType": "span-link" } ], "spanType": "span-bold" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "For most of our history we were losing terribly against the microbes. 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The ", "spanType": "span-simple-text" }, { "children": [ { "text": "germ theory of disease", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "Vaccines get your immune system ready for the battle", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease.\u00a0\u201cThe fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,\u201d as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here ", "spanType": "span-simple-text" }, { "url": "https://moxforum.co.uk/archive/", "children": [ { "text": "moxforum.co.uk/archive/", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": "{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body\u2019s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "Public health: You are only safe if everyone else is safe", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "As is so often the case in development ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/global-inequality-of-opportunity", "children": [ { "text": "you cannot achieve progress by yourself", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". Your progress towards a healthier life depends on everyone else\u2019s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe \u2013 as early as the 17th century \u2013 was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. ", "spanType": "span-simple-text" }, { "children": [ { "text": "The Economic History Review", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", ", "spanType": "span-simple-text" }, { "children": [ { "text": "73", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "(3), E1\u2013E19. ", "spanType": "span-simple-text" }, { "url": "https://doi.org/10.1111/ehr.13019", "children": [ { "text": "https://doi.org/10.1111/ehr.13019", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": "{/ref} ", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an ", "spanType": "span-simple-text" }, { "url": "https://rootsofprogress.org/draining-the-swamp", "children": [ { "text": "excellent overview", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now \u2013 in the COVID-19 pandemic \u2013 that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/identify-covid-exemplars", "children": [ { "text": "here", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ").\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "Infectious diseases before and after the vaccine was introduced", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "How effective were these training sessions against infectious diseases?", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In the ", "spanType": "span-simple-text" }, { "children": [ { "text": "three charts ", "spanType": "span-simple-text" } ], "spanType": "span-bold" }, { "text": "I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "children": [ { "text": "Smallpox", "spanType": "span-simple-text" } ], "spanType": "span-bold" }, { "text": " was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) \u2013 Smallpox: The Death of a Disease - The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref}\u00a0Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/smallpox#vaccine-against-smallpox", "children": [ { "text": "first vaccine ever", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In England in the mid\u2010eighteenth century it was probably the leading cause of death.{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality\u2020. ", "spanType": "span-simple-text" }, { "children": [ { "text": "The Economic History Review", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", ", "spanType": "span-simple-text" }, { "children": [ { "text": "73", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "(3), E1\u2013E19. ", "spanType": "span-simple-text" }, { "url": "https://doi.org/10.1111/ehr.13019", "children": [ { "text": "https://doi.org/10.1111/ehr.13019", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": "{/ref} But in the following century \u2013 as the vaccine reached more people and improved over time \u2013 it became rarer and rarer as a cause of death.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication", "children": [ { "text": "the lives", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " of around 150 to 200 million people since.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/smallpox", "type": "prominent-link", "title": "Our research and data on smallpox", "description": "We eradicated one of the worst infectious diseases globally.", "parseErrors": [] }, { "type": "text", "value": [ { "text": "The history of ", "spanType": "span-simple-text" }, { "children": [ { "text": "polio", "spanType": "span-simple-text" } ], "spanType": "span-bold" }, { "text": " is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient\u2019s breathing muscles.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients\u2019 only chance to survive was to be ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung", "children": [ { "text": "confined to a large, mechanical breathing apparatus", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ": the so-called \u2018iron lungs\u2019.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as \u201cmore than a scientific achievement\u201d according to Salk\u2019s biographer Richard Carter.{ref}\u201cRichard Carter (1966) \u2013 Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, \u201cwas a folk victory, an occasion for pride and jubilation\u2026 people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,\u2026 took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.\u201d", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region", "children": [ { "text": "there were", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at ", "spanType": "span-simple-text" }, { "url": "http://polioeradication.org/polio-today/polio-now/this-week", "children": [ { "text": "polioeradication.org/polio-today/polio-now/this-week", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": "\u00a0 {/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/polio", "type": "prominent-link", "title": "Our research and data on polio.", "description": "With the help of the vaccine we might be able to eradicate polio globally.", "parseErrors": [] }, { "type": "text", "value": [ { "children": [ { "text": "Measles", "spanType": "span-simple-text" } ], "spanType": "span-bold" }, { "text": " too was a major killer for many centuries. The WHO reports: \u201cBefore the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2\u20133 years and measles caused an estimated 2.6 million deaths each year.\u201d{ref}WHO (2019) \u2013 Measles, Key Facts. 5 December 2019. Online here ", "spanType": "span-simple-text" }, { "url": "https://www.who.int/en/news-room/fact-sheets/detail/measles", "children": [ { "text": "https://www.who.int/en/news-room/fact-sheets/detail/measles", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " {/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) \u2013 the average number of secondary cases arising from each case \u2013 range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., & Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. ", "spanType": "span-simple-text" }, { "children": [ { "text": "The Lancet Infectious Diseases", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", ", "spanType": "span-simple-text" }, { "children": [ { "text": "17", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "(12), e420\u2013e428.", "spanType": "span-simple-text" }, { "url": "https://doi.org/10.1016/S1473-3099(17)30307-9", "children": [ { "text": " https://doi.org/10.1016/S1473-3099(17)30307-9", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": "{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Globally we have also made a lot of progress. Today, 85% of one-year olds ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/share-of-children-vaccinated-against-measles?tab=chart&time=1983..2017&country=~OWID_WRL", "children": [ { "text": "receive", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " the measles vaccine and the number of deaths has fallen from 2.6 million ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/deaths-due-to-measles-gbd", "children": [ { "text": "to 83,000 in the latest data", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox.", "spanType": "span-simple-text" }, { "spanType": "span-newline" }, { "text": "See ", "spanType": "span-simple-text" }, { "url": "https://en.wikipedia.org/wiki/Vaccine-preventable_diseases", "children": [ { "text": "https://en.wikipedia.org/wiki/Vaccine-preventable_diseases", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " and ", "spanType": "span-simple-text" }, { "url": "https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/", "children": [ { "text": "https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": "{/ref}", "spanType": "span-simple-text" }, { "spanType": "span-newline" }, { "text": "I selected these three diseases because they protect us from ", "spanType": "span-simple-text" }, { "children": [ { "text": "particularly", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " terrible diseases. And the vaccines for polio and measles stand out because even the very early stage prototypes were very efficacious; the efficacy of many other vaccines increased slowly over time as researchers made adjustments that improved them.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "alt": "", "size": "wide", "type": "image", "filename": "Vaccination-introduction-and-cases-or-deaths.jpg", "parseErrors": [] }, { "text": [ { "text": "Science is our best strategy now", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Some of the best training you ever received were the vaccines you were given in your very early childhood. Without even realizing it, you learned how to battle the pathogens that ravaged the lives of your ancestors for many millennia.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "When humanity achieves very substantial progress it can become difficult to understand what the problems were that we made progress against. This is also the case for vaccine-preventable diseases. Infectious diseases that once disfigured, pained, paralyzed, and killed many of our ancestors have disappeared so far from our lives and memories that some today can afford the luxury of disregarding or even avoiding vaccination.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Today as we face the COVID-19 pandemic, it is the first time for many of us that we experience for one infectious disease what our ancestors experienced for a whole range of them. Just as they were without protection against the diseases discussed previously, we are now facing a pathogen that we have no treatment for and no protection from.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "And now, just as back then, our best hope is science. The responses from ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/covid-exemplar-south-korea", "children": [ { "text": "South Korea", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/covid-exemplar-vietnam", "children": [ { "text": "Vietnam", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", and ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/covid-exemplar-germany", "children": [ { "text": "Germany", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " show that it is possible to fight the disease successfully, but to end the suffering that COVID-19 causes our best hope is a vaccine against the virus.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "We were never better equipped to battle a virus. The genome was sequenced within two weeks and since then scientists around the world have been ", "spanType": "span-simple-text" }, { "url": "https://www.bloomberg.com/news/features/2020-07-15/oxford-s-covid-19-vaccine-is-the-coronavirus-front-runner", "children": [ { "text": "working tirelessly", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " to develop the vaccine that brings the pandemic to an end. The ", "spanType": "span-simple-text" }, { "url": "https://www.ox.ac.uk/news/2020-07-20-new-study-reveals-oxford-coronavirus-vaccine-produces-strong-immune-response", "children": [ { "text": "early results", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " from the vaccine developed here at the University of Oxford are promising.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Our best strategy in the age-old fight against the germs is our collaborative, data-based effort to study the world around us and within us. Our best strategy is science.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "\u2026", "spanType": "span-simple-text" }, { "children": [ { "text": "continue reading on Our World in Data:", "spanType": "span-simple-text" } ], "spanType": "span-italic" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/coronavirus", "type": "prominent-link", "title": "Our data and research on the COVID-19 pandemic", "description": "We currently focus our efforts on the data and research on the COVID-19 pandemic. What does the latest data say? How can we win the battle against COVID-19?", "parseErrors": [] } ], "type": "article", "title": "Our history is a battle against the microbes: we lost terribly before science, public health, and vaccines allowed us to protect ourselves", "authors": [ "Max Roser" ], "excerpt": "For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.", "dateline": "July 20, 2020", "subtitle": "For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.", "sidebar-toc": false, "featured-image": "vaccines-1.png" }, "createdAt": "2020-07-20T16:27:50.000Z", "published": false, "updatedAt": "2022-01-17T14:07:39.000Z", "revisionId": null, "publishedAt": "2020-07-20T15:27:50.000Z", "relatedCharts": [], "publicationContext": "listed" }	{ "errors": [ { "name": "unhandled html tag found", "details": "Encountered the unhandled tag hr" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag separator" }, { "name": "unhandled html tag found", "details": "Encountered the unhandled tag hr" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag separator" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag image" }, { "name": "unhandled html tag found", "details": "Encountered the unhandled tag hr" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag separator" } ], "numBlocks": 49, "numErrors": 7, "wpTagCounts": { "html": 1, "image": 1, "heading": 5, "paragraph": 41, "separator": 3, "owid/prominent-link": 3 }, "htmlTagCounts": { "p": 44, "h4": 2, "h5": 3, "hr": 3, "div": 1, "figure": 1 } }	2020-07-20 15:27:50	2024-02-16 14:22:50	1e0HDWjfdRTrbLlAdUMPGtkqmLJJFw9ookSmgBU6JMPI	[ "Max Roser" ]	For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.	2020-07-20 16:27:50	2022-01-17 14:07:39	https://ourworldindata.org/wp-content/uploads/2020/07/vaccines-1.png	{}	updated version: 21 July 2020 Our World in Data presents the data and research to make progress against the world’s largest problems. This blog post draws on data and research discussed in our entries on [vaccination](https://ourworldindata.org/vaccination) and the [coronavirus pandemic](https://ourworldindata.org/coronavirus). For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough. Humanity’s history is a continuous battle between us and the microbes.{ref}An excellent book on the topic is: Dorothy H. Crawford (2009) – Deadly Companions: How microbes shaped our history.{/ref} For most of our history we were on the losing side. It wasn’t even close. We were losing very decisively. Billions of children died from infectious diseases. They were the main reason why child mortality was so high: No matter where or when they were born, around half died as children. We looked at the evidence of child mortality in pre-modern times [here](https://ourworldindata.org/child-mortality-in-the-past). The recurring epidemics of influenza, measles, cholera, diphtheria, the bubonic plague, and smallpox also killed large parts of the adult population. Within just a few years the Black Death killed half of Europe’s population.{ref}See the time-series of the English population [here](https://ourworldindata.org/grapher/population-of-england-millennium). Mortality was similarly high, or even higher, in other parts of Europe. In his history of the Black Death Ole Jørgen Benedictow suggests that 60% of the population of Europe died in that pandemic. [See Benedictow (2004) – The Black Death 1346–1353: The Complete History.]{/ref} The epidemics – especially of smallpox, but also measles, typhus and other diseases – that the colonialists brought from Europe with them to the Americas often killed an even larger share of the population.{ref}See Noble David Cook (1998) – Born to Die: Disease and New World Conquest, 1492-1650. Cambridge University Press.{/ref} The world today is obviously very different. Infectious diseases are the cause of [fewer than 1-in-6 deaths](https://ourworldindata.org/causes-of-death#causes-of-death-by-category), and as the world made progress against the microbes our lives became much longer. The global average life expectancy is now 73 years after life expectancy [doubled in every world region](https://ourworldindata.org/life-expectancy-globally). ### Until recently no one knew where diseases came from How is it possible that for millennia we were losing the battle against the microbes so awfully and then turned things around in the span of just a few generations? Science is the foundation for our success. 150 years ago nobody knew where diseases came from. Or more precisely, people thought they knew, but they were wrong. The widely accepted idea at the time was the ‘Miasma’ theory of disease. Miasma, the theory held, was a form of "bad air" that causes disease. The word _malaria_ is testament to the idea that ‘mal aria’ – ‘bad air’ in medieval Italian – is the cause of the disease. Thanks to the work of a number of doctors and chemists in the second half of the 19th century humanity learned that not noxious air, but specific germs cause infectious diseases. The _germ theory of disease_ was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines. ### Vaccines get your immune system ready for the battle Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease. “The fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,” as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here [moxforum.co.uk/archive/](https://moxforum.co.uk/archive/){/ref} The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body’s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen. ### Public health: You are only safe if everyone else is safe Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection. As is so often the case in development [you cannot achieve progress by yourself](https://ourworldindata.org/global-inequality-of-opportunity). Your progress towards a healthier life depends on everyone else’s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs. Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe – as early as the 17th century – was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. _The Economic History Review_, _73_(3), E1–E19. [https://doi.org/10.1111/ehr.13019](https://doi.org/10.1111/ehr.13019){/ref} Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an [excellent overview](https://rootsofprogress.org/draining-the-swamp) of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century. Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now – in the COVID-19 pandemic – that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this [here](https://ourworldindata.org/identify-covid-exemplars)). ## Infectious diseases before and after the vaccine was introduced How effective were these training sessions against infectious diseases? In the three charts I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available. Smallpox was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) – Smallpox: The Death of a Disease - The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref} Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very [first vaccine ever](https://ourworldindata.org/smallpox#vaccine-against-smallpox). In England in the mid‐eighteenth century it was probably the leading cause of death.{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality†. _The Economic History Review_, _73_(3), E1–E19. [https://doi.org/10.1111/ehr.13019](https://doi.org/10.1111/ehr.13019){/ref} But in the following century – as the vaccine reached more people and improved over time – it became rarer and rarer as a cause of death. Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved [the lives](https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication) of around 150 to 200 million people since. ### Our research and data on smallpox We eradicated one of the worst infectious diseases globally. https://ourworldindata.org/smallpox The history of polio is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient’s breathing muscles. The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients’ only chance to survive was to be [confined to a large, mechanical breathing apparatus](https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung): the so-called ‘iron lungs’. The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as “more than a scientific achievement” according to Salk’s biographer Richard Carter.{ref}“Richard Carter (1966) – Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, “was a folk victory, an occasion for pride and jubilation… people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,… took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.” As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free. Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s [there were](https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region) between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at [polioeradication.org/polio-today/polio-now/this-week](http://polioeradication.org/polio-today/polio-now/this-week) {/ref} ### Our research and data on polio. With the help of the vaccine we might be able to eradicate polio globally. https://ourworldindata.org/polio Measles too was a major killer for many centuries. The WHO reports: “Before the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2–3 years and measles caused an estimated 2.6 million deaths each year.”{ref}WHO (2019) – Measles, Key Facts. 5 December 2019. Online here [https://www.who.int/en/news-room/fact-sheets/detail/measles](https://www.who.int/en/news-room/fact-sheets/detail/measles) {/ref} Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) – the average number of secondary cases arising from each case – range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., & Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. _The Lancet Infectious Diseases_, _17_(12), e420–e428.[ https://doi.org/10.1016/S1473-3099(17)30307-9](https://doi.org/10.1016/S1473-3099(17)30307-9){/ref} The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families. Globally we have also made a lot of progress. Today, 85% of one-year olds [receive](https://ourworldindata.org/grapher/share-of-children-vaccinated-against-measles?tab=chart&time=1983..2017&country=~OWID_WRL) the measles vaccine and the number of deaths has fallen from 2.6 million [to 83,000 in the latest data](https://ourworldindata.org/grapher/deaths-due-to-measles-gbd). Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox. See [https://en.wikipedia.org/wiki/Vaccine-preventable_diseases](https://en.wikipedia.org/wiki/Vaccine-preventable_diseases) and [https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/](https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/){/ref} I selected these three diseases because they protect us from _particularly_ terrible diseases. And the vaccines for polio and measles stand out because even the very early stage prototypes were very efficacious; the efficacy of many other vaccines increased slowly over time as researchers made adjustments that improved them. <Image filename="Vaccination-introduction-and-cases-or-deaths.jpg" alt=""/> ## Science is our best strategy now Some of the best training you ever received were the vaccines you were given in your very early childhood. Without even realizing it, you learned how to battle the pathogens that ravaged the lives of your ancestors for many millennia. When humanity achieves very substantial progress it can become difficult to understand what the problems were that we made progress against. This is also the case for vaccine-preventable diseases. Infectious diseases that once disfigured, pained, paralyzed, and killed many of our ancestors have disappeared so far from our lives and memories that some today can afford the luxury of disregarding or even avoiding vaccination. Today as we face the COVID-19 pandemic, it is the first time for many of us that we experience for one infectious disease what our ancestors experienced for a whole range of them. Just as they were without protection against the diseases discussed previously, we are now facing a pathogen that we have no treatment for and no protection from. And now, just as back then, our best hope is science. The responses from [South Korea](https://ourworldindata.org/covid-exemplar-south-korea), [Vietnam](https://ourworldindata.org/covid-exemplar-vietnam), and [Germany](https://ourworldindata.org/covid-exemplar-germany) show that it is possible to fight the disease successfully, but to end the suffering that COVID-19 causes our best hope is a vaccine against the virus. We were never better equipped to battle a virus. The genome was sequenced within two weeks and since then scientists around the world have been [working tirelessly](https://www.bloomberg.com/news/features/2020-07-15/oxford-s-covid-19-vaccine-is-the-coronavirus-front-runner) to develop the vaccine that brings the pandemic to an end. The [early results](https://www.ox.ac.uk/news/2020-07-20-new-study-reveals-oxford-coronavirus-vaccine-produces-strong-immune-response) from the vaccine developed here at the University of Oxford are promising. Our best strategy in the age-old fight against the germs is our collaborative, data-based effort to study the world around us and within us. Our best strategy is science. …_continue reading on Our World in Data:_ ### Our data and research on the COVID-19 pandemic We currently focus our efforts on the data and research on the COVID-19 pandemic. What does the latest data say? How can we win the battle against COVID-19? https://ourworldindata.org/coronavirus	{ "id": 35067, "date": "2020-07-20T16:27:50", "guid": { "rendered": "https://owid.cloud/?p=35067" }, "link": "https://owid.cloud/microbes-battle-science-vaccines", "meta": { "owid_publication_context_meta_field": { "latest": true, "homepage": true, "immediate_newsletter": true } }, "slug": "microbes-battle-science-vaccines", "tags": [], "type": "post", "title": { "rendered": "Our history is a battle against the microbes: we lost terribly before science, public health, and vaccines allowed us to protect ourselves" }, "_links": { "self": [ { "href": "https://owid.cloud/wp-json/wp/v2/posts/35067" } ], "about": [ { "href": "https://owid.cloud/wp-json/wp/v2/types/post" } ], "author": [ { "href": "https://owid.cloud/wp-json/wp/v2/users/2", "embeddable": true } ], "curies": [ { "href": "https://api.w.org/{rel}", "name": "wp", "templated": true } ], "replies": [ { "href": "https://owid.cloud/wp-json/wp/v2/comments?post=35067", "embeddable": true } ], "wp:term": [ { "href": "https://owid.cloud/wp-json/wp/v2/categories?post=35067", "taxonomy": "category", "embeddable": true }, { "href": "https://owid.cloud/wp-json/wp/v2/tags?post=35067", "taxonomy": "post_tag", "embeddable": true } ], "collection": [ { "href": "https://owid.cloud/wp-json/wp/v2/posts" } ], "wp:attachment": [ { "href": "https://owid.cloud/wp-json/wp/v2/media?parent=35067" } ], "version-history": [ { "href": "https://owid.cloud/wp-json/wp/v2/posts/35067/revisions", "count": 28 } ], "wp:featuredmedia": [ { "href": "https://owid.cloud/wp-json/wp/v2/media/35631", "embeddable": true } ], "predecessor-version": [ { "id": 47819, "href": "https://owid.cloud/wp-json/wp/v2/posts/35067/revisions/47819" } ] }, "author": 2, "format": "standard", "status": "publish", "sticky": false, "content": { "rendered": "\n<div class=\"blog-info\">\n<p>updated version: 21 July 2020</p>\n<p>Our World in Data presents the data and research to make progress against the world\u2019s largest problems.<br>This blog post draws on data and research discussed in our entries on <strong><a href=\"https://ourworldindata.org/vaccination\" target=\"_blank\" rel=\"noopener noreferrer\">vaccination</a></strong> and the <strong><a href=\"https://ourworldindata.org/coronavirus\" target=\"_blank\" rel=\"noopener noreferrer\">coronavirus pandemic</a></strong>.</p>\n<p>For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.</p>\n</div>\n\n\n\n<p>Humanity\u2019s history is a continuous battle between us and the microbes.{ref}An excellent book on the topic is: Dorothy H. Crawford  (2009) \u2013 Deadly Companions: How microbes shaped our history.{/ref} For most of our history we were on the losing side.</p>\n\n\n\n<p>It wasn\u2019t even close. We were losing very decisively. Billions of children died from infectious diseases. They were the main reason why child mortality was so high: No matter where or when they were born, around half died as children. We looked at the evidence of child mortality in pre-modern times <a href=\"https://ourworldindata.org/child-mortality-in-the-past\">here</a>. </p>\n\n\n\n<p>The recurring epidemics of influenza, measles, cholera, diphtheria, the bubonic plague, and smallpox also killed large parts of the adult population. Within just a few years the Black Death killed half of Europe\u2019s population.{ref}See the time-series of the English population <a href=\"https://ourworldindata.org/grapher/population-of-england-millennium\">here</a>.<br>Mortality was similarly high, or even higher, in other parts of Europe.</p>\n\n\n\n<p>In his history of the Black Death Ole J\u00f8rgen Benedictow suggests that 60% of the population of Europe died in that pandemic. [See Benedictow (2004) \u2013 The Black Death 1346\u20131353: The Complete History.]{/ref} The epidemics \u2013 especially of smallpox, but also measles, typhus and other diseases \u2013 that the colonialists brought from Europe with them to the Americas often killed an even larger share of the population.{ref}See Noble David Cook (1998) \u2013 Born to Die: Disease and New World Conquest, 1492-1650. Cambridge University Press.{/ref}</p>\n\n\n\n<p>The world today is obviously very different. Infectious diseases are the cause of <a href=\"https://ourworldindata.org/causes-of-death#causes-of-death-by-category\">fewer than 1-in-6 deaths</a>, and as the world made progress against the microbes our lives became much longer. The global average life expectancy is now 73 years after life expectancy <a href=\"https://ourworldindata.org/life-expectancy-globally\">doubled in every world region</a>.</p>\n\n\n\n<h5>Until recently no one knew where diseases came from</h5>\n\n\n\n<p>How is it possible that for millennia we were losing the battle against the microbes so awfully and then turned things around in the span of just a few generations?</p>\n\n\n\n<p>Science is the foundation for our success. 150 years ago nobody knew where diseases came from. Or more precisely, people thought they knew, but they were wrong. The widely accepted idea at the time was the \u2018Miasma\u2019 theory of disease. Miasma, the theory held, was a form of “bad air” that causes disease. The word <em>malaria</em> is testament to the idea that \u2018mal aria\u2019 \u2013 \u2018bad air\u2019 in medieval Italian \u2013 is the cause of the disease.</p>\n\n\n\n<p>Thanks to the work of a number of doctors and chemists in the second half of the 19th century humanity learned that not noxious air, but specific germs cause infectious diseases. The <em>germ theory of disease</em> was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines. </p>\n\n\n\n<h5>Vaccines get your immune system ready for the battle</h5>\n\n\n\n<p>Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease. \u201cThe fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,\u201d as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here <a href=\"https://moxforum.co.uk/archive/\">moxforum.co.uk/archive/</a>{/ref}</p>\n\n\n\n<p>The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body\u2019s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen.</p>\n\n\n\n<h5>Public health: You are only safe if everyone else is safe</h5>\n\n\n\n<p>Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection.</p>\n\n\n\n<p>As is so often the case in development <a href=\"https://ourworldindata.org/global-inequality-of-opportunity\">you cannot achieve progress by yourself</a>. Your progress towards a healthier life depends on everyone else\u2019s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs.</p>\n\n\n\n<p>Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe \u2013 as early as the 17th century \u2013 was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. <em>The Economic History Review</em>, <em>73</em>(3), E1\u2013E19. <a href=\"https://doi.org/10.1111/ehr.13019\">https://doi.org/10.1111/ehr.13019</a>{/ref} </p>\n\n\n\n<p>Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an <a href=\"https://rootsofprogress.org/draining-the-swamp\">excellent overview</a> of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century.</p>\n\n\n\n<p>Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now \u2013 in the COVID-19 pandemic \u2013 that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this <a href=\"https://ourworldindata.org/identify-covid-exemplars\">here</a>). </p>\n\n\n\n<h4>Infectious diseases before and after the vaccine was introduced</h4>\n\n\n\n<p>How effective were these training sessions against infectious diseases?</p>\n\n\n\n<p>In the <strong>three charts </strong>I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available.</p>\n\n\n\n<p><strong>Smallpox</strong> was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) \u2013 Smallpox: The Death of a Disease – The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref} Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very <a href=\"https://ourworldindata.org/smallpox#vaccine-against-smallpox\">first vaccine ever</a>.</p>\n\n\n\n<p>In England in the mid\u2010eighteenth century it was probably the leading cause of death.{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality\u2020. <em>The Economic History Review</em>, <em>73</em>(3), E1\u2013E19. <a href=\"https://doi.org/10.1111/ehr.13019\">https://doi.org/10.1111/ehr.13019</a>{/ref} But in the following century \u2013 as the vaccine reached more people and improved over time \u2013 it became rarer and rarer as a cause of death.</p>\n\n\n\n<p>Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved <a href=\"https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication\">the lives</a> of around 150 to 200 million people since.</p>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/smallpox</link-url>\n <title>Our research and data on smallpox</title>\n <content>\n\n<p>We eradicated one of the worst infectious diseases globally.</p>\n\n</content>\n <figure><img width=\"768\" height=\"542\" src=\"https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-768x542.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-768x542.png 768w, https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-150x106.png 150w, https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-400x282.png 400w, https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-750x529.png 750w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n </block>\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<p>The history of <strong>polio</strong> is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient\u2019s breathing muscles. </p>\n\n\n\n<p>The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients\u2019 only chance to survive was to be <a href=\"https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung\">confined to a large, mechanical breathing apparatus</a>: the so-called \u2018iron lungs\u2019. </p>\n\n\n\n<p>The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as \u201cmore than a scientific achievement\u201d according to Salk\u2019s biographer Richard Carter.{ref}\u201cRichard Carter (1966) \u2013 Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, \u201cwas a folk victory, an occasion for pride and jubilation\u2026 people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,\u2026 took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.\u201d</p>\n\n\n\n<p>As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free. </p>\n\n\n\n<p>Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s <a href=\"https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region\">there were</a> between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at <a href=\"http://polioeradication.org/polio-today/polio-now/this-week\">polioeradication.org/polio-today/polio-now/this-week</a>  {/ref}</p>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/polio</link-url>\n <title>Our research and data on polio.</title>\n <content>\n\n<p>With the help of the vaccine we might be able to eradicate polio globally.</p>\n\n</content>\n <figure><img width=\"768\" height=\"542\" src=\"https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-768x542.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-768x542.png 768w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-150x106.png 150w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-400x282.png 400w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-750x529.png 750w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region.png 2040w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n </block>\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<p><strong>Measles</strong> too was a major killer for many centuries. The WHO reports: \u201cBefore the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2\u20133 years and measles caused an estimated 2.6 million deaths each year.\u201d{ref}WHO (2019) \u2013 Measles, Key Facts. 5 December 2019. Online here <a href=\"https://www.who.int/en/news-room/fact-sheets/detail/measles\">https://www.who.int/en/news-room/fact-sheets/detail/measles</a> {/ref}</p>\n\n\n\n<p>Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) \u2013 the average number of secondary cases arising from each case \u2013 range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., & Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. <em>The Lancet Infectious Diseases</em>, <em>17</em>(12), e420\u2013e428.<a href=\"https://doi.org/10.1016/S1473-3099(17)30307-9\"> https://doi.org/10.1016/S1473-3099(17)30307-9</a>{/ref}</p>\n\n\n\n<p>The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families.</p>\n\n\n\n<p>Globally we have also made a lot of progress. Today, 85% of one-year olds <a href=\"https://ourworldindata.org/grapher/share-of-children-vaccinated-against-measles?tab=chart&time=1983..2017&country=~OWID_WRL\">receive</a> the measles vaccine and the number of deaths has fallen from 2.6 million <a href=\"https://ourworldindata.org/grapher/deaths-due-to-measles-gbd\">to 83,000 in the latest data</a>.\u00a0</p>\n\n\n\n<p>Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox.<br>See <a href=\"https://en.wikipedia.org/wiki/Vaccine-preventable_diseases\">https://en.wikipedia.org/wiki/Vaccine-preventable_diseases</a> and <a href=\"https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/\">https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/</a>{/ref}<br>I selected these three diseases because they protect us from <em>particularly</em> terrible diseases. And the vaccines for polio and measles stand out because even the very early stage prototypes were very efficacious; the efficacy of many other vaccines increased slowly over time as researchers made adjustments that improved them.</p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" width=\"1403\" height=\"1966\" src=\"https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths.jpg\" alt=\"\" class=\"wp-image-39984\" srcset=\"https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths.jpg 1403w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-285x400.jpg 285w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-392x550.jpg 392w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-107x150.jpg 107w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-768x1076.jpg 768w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-1096x1536.jpg 1096w\" sizes=\"(max-width: 1403px) 100vw, 1403px\" /></figure>\n\n\n\n<h4>Science is our best strategy now</h4>\n\n\n\n<p>Some of the best training you ever received were the vaccines you were given in your very early childhood. Without even realizing it, you learned how to battle the pathogens that ravaged the lives of your ancestors for many millennia.</p>\n\n\n\n<p>When humanity achieves very substantial progress it can become difficult to understand what the problems were that we made progress against. This is also the case for vaccine-preventable diseases. Infectious diseases that once disfigured, pained, paralyzed, and killed many of our ancestors have disappeared so far from our lives and memories that some today can afford the luxury of disregarding or even avoiding vaccination.</p>\n\n\n\n<p>Today as we face the COVID-19 pandemic, it is the first time for many of us that we experience for one infectious disease what our ancestors experienced for a whole range of them. Just as they were without protection against the diseases discussed previously, we are now facing a pathogen that we have no treatment for and no protection from. </p>\n\n\n\n<p>And now, just as back then, our best hope is science. The responses from <a href=\"https://ourworldindata.org/covid-exemplar-south-korea\">South Korea</a>, <a href=\"https://ourworldindata.org/covid-exemplar-vietnam\">Vietnam</a>, and <a href=\"https://ourworldindata.org/covid-exemplar-germany\">Germany</a> show that it is possible to fight the disease successfully, but to end the suffering that COVID-19 causes our best hope is a vaccine against the virus. </p>\n\n\n\n<p>We were never better equipped to battle a virus. The genome was sequenced within two weeks and since then scientists around the world have been <a href=\"https://www.bloomberg.com/news/features/2020-07-15/oxford-s-covid-19-vaccine-is-the-coronavirus-front-runner\">working tirelessly</a> to develop the vaccine that brings the pandemic to an end. The <a href=\"https://www.ox.ac.uk/news/2020-07-20-new-study-reveals-oxford-coronavirus-vaccine-produces-strong-immune-response\">early results</a> from the vaccine developed here at the University of Oxford are promising.</p>\n\n\n\n<p>Our best strategy in the age-old fight against the germs is our collaborative, data-based effort to study the world around us and within us. Our best strategy is science.</p>\n\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<p>\u2026<em>continue reading on Our World in Data:</em></p>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/coronavirus</link-url>\n <title>Our data and research on the COVID-19 pandemic</title>\n <content>\n\n<p>We currently focus our efforts on the data and research on the COVID-19 pandemic. What does the latest data say? How can we win the battle against COVID-19?</p>\n\n</content>\n <figure><img width=\"768\" height=\"463\" src=\"https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-768x463.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-768x463.png 768w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-400x241.png 400w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-800x482.png 800w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-150x90.png 150w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-1536x926.png 1536w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18.png 1914w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n </block>\n\n\n<p></p>\n", "protected": false }, "excerpt": { "rendered": "For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.", "protected": false }, "date_gmt": "2020-07-20T15:27:50", "modified": "2022-01-17T14:07:39", "template": "", "categories": [ 1 ], "ping_status": "closed", "authors_name": [ "Max Roser" ], "modified_gmt": "2022-01-17T14:07:39", "comment_status": "closed", "featured_media": 35631, "featured_media_paths": { "thumbnail": "/app/uploads/2020/07/vaccines-1-150x79.png", "medium_large": "/app/uploads/2020/07/vaccines-1-768x403.png" } }

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Our history is a battle against the microbes: we lost terribly before science, public health, and vaccines allowed us to protect ourselves

microbes-battle-science-vaccines

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<div class="blog-info"> updated version: 21 July 2020 Our World in Data presents the data and research to make progress against the world’s largest problems. This blog post draws on data and research discussed in our entries on <a href="https://ourworldindata.org/vaccination" target="_blank" rel="noopener noreferrer">vaccination</a> and the <a href="https://ourworldindata.org/coronavirus" target="_blank" rel="noopener noreferrer">coronavirus pandemic</a>. For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough. </div>   Humanity’s history is a continuous battle between us and the microbes.{ref}An excellent book on the topic is: Dorothy H. Crawford  (2009) – Deadly Companions: How microbes shaped our history.{/ref} For most of our history we were on the losing side.   It wasn’t even close. We were losing very decisively. Billions of children died from infectious diseases. They were the main reason why child mortality was so high: No matter where or when they were born, around half died as children. We looked at the evidence of child mortality in pre-modern times <a href="https://ourworldindata.org/child-mortality-in-the-past">here</a>.    The recurring epidemics of influenza, measles, cholera, diphtheria, the bubonic plague, and smallpox also killed large parts of the adult population. Within just a few years the Black Death killed half of Europe’s population.{ref}See the time-series of the English population <a href="https://ourworldindata.org/grapher/population-of-england-millennium">here</a>. Mortality was similarly high, or even higher, in other parts of Europe.   In his history of the Black Death Ole Jørgen Benedictow suggests that 60% of the population of Europe died in that pandemic. [See Benedictow (2004) – The Black Death 1346–1353: The Complete History.]{/ref} The epidemics – especially of smallpox, but also measles, typhus and other diseases – that the colonialists brought from Europe with them to the Americas often killed an even larger share of the population.{ref}See Noble David Cook (1998) – Born to Die: Disease and New World Conquest, 1492-1650. Cambridge University Press.{/ref}   The world today is obviously very different. Infectious diseases are the cause of <a href="https://ourworldindata.org/causes-of-death#causes-of-death-by-category">fewer than 1-in-6 deaths</a>, and as the world made progress against the microbes our lives became much longer. The global average life expectancy is now 73 years after life expectancy <a href="https://ourworldindata.org/life-expectancy-globally">doubled in every world region</a>.   <h5>Until recently no one knew where diseases came from</h5>   How is it possible that for millennia we were losing the battle against the microbes so awfully and then turned things around in the span of just a few generations?   Science is the foundation for our success. 150 years ago nobody knew where diseases came from. Or more precisely, people thought they knew, but they were wrong. The widely accepted idea at the time was the ‘Miasma’ theory of disease. Miasma, the theory held, was a form of "bad air" that causes disease. The word malaria is testament to the idea that ‘mal aria’ – ‘bad air’ in medieval Italian – is the cause of the disease.   Thanks to the work of a number of doctors and chemists in the second half of the 19th century humanity learned that not noxious air, but specific germs cause infectious diseases. The germ theory of disease was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines.    <h5>Vaccines get your immune system ready for the battle</h5>   Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease. “The fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,” as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here <a href="https://moxforum.co.uk/archive/">moxforum.co.uk/archive/</a>{/ref}   The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body’s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen.   <h5>Public health: You are only safe if everyone else is safe</h5>   Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection.   As is so often the case in development <a href="https://ourworldindata.org/global-inequality-of-opportunity">you cannot achieve progress by yourself</a>. Your progress towards a healthier life depends on everyone else’s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs.   Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe – as early as the 17th century – was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. The Economic History Review, 73(3), E1–E19. <a href="https://doi.org/10.1111/ehr.13019">https://doi.org/10.1111/ehr.13019</a>{/ref}   Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an <a href="https://rootsofprogress.org/draining-the-swamp">excellent overview</a> of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century.   Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now – in the COVID-19 pandemic – that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this <a href="https://ourworldindata.org/identify-covid-exemplars">here</a>).    <h4>Infectious diseases before and after the vaccine was introduced</h4>   How effective were these training sessions against infectious diseases?   In the three charts I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available.   Smallpox was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) – Smallpox: The Death of a Disease - The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref} Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very <a href="https://ourworldindata.org/smallpox#vaccine-against-smallpox">first vaccine ever</a>.   In England in the mid‐eighteenth century it was probably the leading cause of death.{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality†. The Economic History Review, 73(3), E1–E19. <a href="https://doi.org/10.1111/ehr.13019">https://doi.org/10.1111/ehr.13019</a>{/ref} But in the following century – as the vaccine reached more people and improved over time – it became rarer and rarer as a cause of death.   Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved <a href="https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication">the lives</a> of around 150 to 200 million people since.    We eradicated one of the worst infectious diseases globally.    <hr class="wp-block-separator"/>   The history of polio is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient’s breathing muscles.    The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients’ only chance to survive was to be <a href="https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung">confined to a large, mechanical breathing apparatus</a>: the so-called ‘iron lungs’.    The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as “more than a scientific achievement” according to Salk’s biographer Richard Carter.{ref}“Richard Carter (1966) – Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, “was a folk victory, an occasion for pride and jubilation… people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,… took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.”   As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free.    Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s <a href="https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region">there were</a> between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at <a href="http://polioeradication.org/polio-today/polio-now/this-week">polioeradication.org/polio-today/polio-now/this-week</a>  {/ref}    With the help of the vaccine we might be able to eradicate polio globally.    <hr class="wp-block-separator"/>   Measles too was a major killer for many centuries. The WHO reports: “Before the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2–3 years and measles caused an estimated 2.6 million deaths each year.”{ref}WHO (2019) – Measles, Key Facts. 5 December 2019. Online here <a href="https://www.who.int/en/news-room/fact-sheets/detail/measles">https://www.who.int/en/news-room/fact-sheets/detail/measles</a> {/ref}   Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) – the average number of secondary cases arising from each case – range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., & Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. The Lancet Infectious Diseases, 17(12), e420–e428.<a href="https://doi.org/10.1016/S1473-3099(17)30307-9"> https://doi.org/10.1016/S1473-3099(17)30307-9</a>{/ref}   The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families.   Globally we have also made a lot of progress. Today, 85% of one-year olds <a href="https://ourworldindata.org/grapher/share-of-children-vaccinated-against-measles?tab=chart&time=1983..2017&country=~OWID_WRL">receive</a> the measles vaccine and the number of deaths has fallen from 2.6 million <a href="https://ourworldindata.org/grapher/deaths-due-to-measles-gbd">to 83,000 in the latest data</a>.   Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox. See <a href="https://en.wikipedia.org/wiki/Vaccine-preventable_diseases">https://en.wikipedia.org/wiki/Vaccine-preventable_diseases</a> and <a href="https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/">https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/</a>{/ref} I selected these three diseases because they protect us from particularly terrible diseases. And the vaccines for polio and measles stand out because even the very early stage prototypes were very efficacious; the efficacy of many other vaccines increased slowly over time as researchers made adjustments that improved them.   <figure class="wp-block-image size-full"><img src="https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths.jpg" alt="" class="wp-image-39984"/></figure>   <h4>Science is our best strategy now</h4>   Some of the best training you ever received were the vaccines you were given in your very early childhood. Without even realizing it, you learned how to battle the pathogens that ravaged the lives of your ancestors for many millennia.   When humanity achieves very substantial progress it can become difficult to understand what the problems were that we made progress against. This is also the case for vaccine-preventable diseases. Infectious diseases that once disfigured, pained, paralyzed, and killed many of our ancestors have disappeared so far from our lives and memories that some today can afford the luxury of disregarding or even avoiding vaccination.   Today as we face the COVID-19 pandemic, it is the first time for many of us that we experience for one infectious disease what our ancestors experienced for a whole range of them. Just as they were without protection against the diseases discussed previously, we are now facing a pathogen that we have no treatment for and no protection from.    And now, just as back then, our best hope is science. The responses from <a href="https://ourworldindata.org/covid-exemplar-south-korea">South Korea</a>, <a href="https://ourworldindata.org/covid-exemplar-vietnam">Vietnam</a>, and <a href="https://ourworldindata.org/covid-exemplar-germany">Germany</a> show that it is possible to fight the disease successfully, but to end the suffering that COVID-19 causes our best hope is a vaccine against the virus.    We were never better equipped to battle a virus. The genome was sequenced within two weeks and since then scientists around the world have been <a href="https://www.bloomberg.com/news/features/2020-07-15/oxford-s-covid-19-vaccine-is-the-coronavirus-front-runner">working tirelessly</a> to develop the vaccine that brings the pandemic to an end. The <a href="https://www.ox.ac.uk/news/2020-07-20-new-study-reveals-oxford-coronavirus-vaccine-produces-strong-immune-response">early results</a> from the vaccine developed here at the University of Oxford are promising.   Our best strategy in the age-old fight against the germs is our collaborative, data-based effort to study the world around us and within us. Our best strategy is science.   <hr class="wp-block-separator"/>   …continue reading on Our World in Data:    We currently focus our efforts on the data and research on the COVID-19 pandemic. What does the latest data say? How can we win the battle against COVID-19?

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                        "text": "Our World in Data presents the data and research to make progress against the world\u2019s largest problems.",
                        "spanType": "span-simple-text"
                    },
                    {
                        "spanType": "span-newline"
                    },
                    {
                        "text": "This blog post draws on data and research discussed in our entries on ",
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                    },
                    {
                        "children": [
                            {
                                "url": "https://ourworldindata.org/vaccination",
                                "children": [
                                    {
                                        "text": "vaccination",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            }
                        ],
                        "spanType": "span-bold"
                    },
                    {
                        "text": " and the ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "url": "https://ourworldindata.org/coronavirus",
                                "children": [
                                    {
                                        "text": "coronavirus pandemic",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            }
                        ],
                        "spanType": "span-bold"
                    },
                    {
                        "text": ".",
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                    }
                ],
                "parseErrors": []
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                "type": "text",
                "value": [
                    {
                        "text": "For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.",
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                ],
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                "type": "text",
                "value": [
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                        "text": "Humanity\u2019s history is a continuous battle between us and the microbes.{ref}An excellent book on the topic is: Dorothy H. Crawford\u00a0 (2009) \u2013 Deadly Companions: How microbes shaped our history.{/ref} For most of our history we were on the losing side.",
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "It wasn\u2019t even close. We were losing very decisively. Billions of children died from infectious diseases. They were the main reason why child mortality was so high: No matter where or when they were born, around half died as children. We looked at the evidence of child mortality in pre-modern times ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/child-mortality-in-the-past",
                        "children": [
                            {
                                "text": "here",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ".\u00a0",
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "The recurring epidemics of influenza, measles, cholera, diphtheria, the bubonic plague, and smallpox also killed large parts of the adult population. Within just a few years the Black Death killed half of Europe\u2019s population.{ref}See the time-series of the English population ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/grapher/population-of-england-millennium",
                        "children": [
                            {
                                "text": "here",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ".",
                        "spanType": "span-simple-text"
                    },
                    {
                        "spanType": "span-newline"
                    },
                    {
                        "text": "Mortality was similarly high, or even higher, in other parts of Europe.",
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                ],
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            {
                "type": "text",
                "value": [
                    {
                        "text": "In his history of the Black Death Ole J\u00f8rgen Benedictow suggests that 60% of the population of Europe died in that pandemic. [See Benedictow (2004) \u2013 The Black Death 1346\u20131353: The Complete History.]{/ref} The epidemics \u2013 especially of smallpox, but also measles, typhus and other diseases \u2013 that the colonialists brought from Europe with them to the Americas often killed an even larger share of the population.{ref}See Noble David Cook (1998) \u2013 Born to Die: Disease and New World Conquest, 1492-1650. Cambridge University Press.{/ref}",
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                    }
                ],
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                "type": "text",
                "value": [
                    {
                        "text": "The world today is obviously very different. Infectious diseases are the cause of ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/causes-of-death#causes-of-death-by-category",
                        "children": [
                            {
                                "text": "fewer than 1-in-6 deaths",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ", and as the world made progress against the microbes our lives became much longer. The global average life expectancy is now 73 years after life expectancy ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/life-expectancy-globally",
                        "children": [
                            {
                                "text": "doubled in every world region",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ".",
                        "spanType": "span-simple-text"
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                ],
                "parseErrors": []
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            {
                "text": [
                    {
                        "text": "Until recently no one knew where diseases came from",
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                    }
                ],
                "type": "heading",
                "level": 3,
                "parseErrors": []
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                "type": "text",
                "value": [
                    {
                        "text": "How is it possible that for millennia we were losing the battle against the microbes so awfully and then turned things around in the span of just a few generations?",
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                    }
                ],
                "parseErrors": []
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                "type": "text",
                "value": [
                    {
                        "text": "Science is the foundation for our success. 150 years ago nobody knew where diseases came from. Or more precisely, people thought they knew, but they were wrong.\u00a0The widely accepted idea at the time was the \u2018Miasma\u2019 theory of disease. Miasma, the theory held, was a form of \"bad air\" that causes disease. The word ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "malaria",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": " is testament to the idea that \u2018mal aria\u2019 \u2013 \u2018bad air\u2019 in medieval Italian \u2013 is the cause of the disease.",
                        "spanType": "span-simple-text"
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "Thanks to the work of a number of doctors and chemists in the second half of the 19th century humanity learned that not noxious air, but specific germs cause infectious diseases. The ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "germ theory of disease",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-italic"
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                    {
                        "text": " was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines.\u00a0",
                        "spanType": "span-simple-text"
                    }
                ],
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            {
                "text": [
                    {
                        "text": "Vaccines get your immune system ready for the battle",
                        "spanType": "span-simple-text"
                    }
                ],
                "type": "heading",
                "level": 3,
                "parseErrors": []
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                "type": "text",
                "value": [
                    {
                        "text": "Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease.\u00a0\u201cThe fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,\u201d as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://moxforum.co.uk/archive/",
                        "children": [
                            {
                                "text": "moxforum.co.uk/archive/",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": "{/ref}",
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body\u2019s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen.",
                        "spanType": "span-simple-text"
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                ],
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            {
                "text": [
                    {
                        "text": "Public health: You are only safe if everyone else is safe",
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                    }
                ],
                "type": "heading",
                "level": 3,
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                        "text": "Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection.",
                        "spanType": "span-simple-text"
                    }
                ],
                "parseErrors": []
            },
            {
                "type": "text",
                "value": [
                    {
                        "text": "As is so often the case in development ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/global-inequality-of-opportunity",
                        "children": [
                            {
                                "text": "you cannot achieve progress by yourself",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". Your progress towards a healthier life depends on everyone else\u2019s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs.",
                        "spanType": "span-simple-text"
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                ],
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                "type": "text",
                "value": [
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                        "text": "Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe \u2013 as early as the 17th century \u2013 was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The Economic History Review",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", ",
                        "spanType": "span-simple-text"
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                    {
                        "children": [
                            {
                                "text": "73",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
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                    {
                        "text": "(3), E1\u2013E19. ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://doi.org/10.1111/ehr.13019",
                        "children": [
                            {
                                "text": "https://doi.org/10.1111/ehr.13019",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": "{/ref} ",
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                        "text": "Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://rootsofprogress.org/draining-the-swamp",
                        "children": [
                            {
                                "text": "excellent overview",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century.",
                        "spanType": "span-simple-text"
                    }
                ],
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                "type": "text",
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                        "text": "Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now \u2013 in the COVID-19 pandemic \u2013 that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/identify-covid-exemplars",
                        "children": [
                            {
                                "text": "here",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ").\u00a0",
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                ],
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                "text": [
                    {
                        "text": "Infectious diseases before and after the vaccine was introduced",
                        "spanType": "span-simple-text"
                    }
                ],
                "type": "heading",
                "level": 2,
                "parseErrors": []
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                "type": "text",
                "value": [
                    {
                        "text": "How effective were these training sessions against infectious diseases?",
                        "spanType": "span-simple-text"
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "In the ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "three charts ",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-bold"
                    },
                    {
                        "text": "I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available.",
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                ],
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            {
                "type": "text",
                "value": [
                    {
                        "children": [
                            {
                                "text": "Smallpox",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-bold"
                    },
                    {
                        "text": " was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) \u2013 Smallpox: The Death of a Disease - The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref}\u00a0Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/smallpox#vaccine-against-smallpox",
                        "children": [
                            {
                                "text": "first vaccine ever",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ".",
                        "spanType": "span-simple-text"
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                ],
                "parseErrors": []
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            {
                "type": "text",
                "value": [
                    {
                        "text": "In England in the mid\u2010eighteenth century it was probably the leading cause of death.{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality\u2020. ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The Economic History Review",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": ", ",
                        "spanType": "span-simple-text"
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                        "children": [
                            {
                                "text": "73",
                                "spanType": "span-simple-text"
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                        ],
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                    {
                        "text": "(3), E1\u2013E19. ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://doi.org/10.1111/ehr.13019",
                        "children": [
                            {
                                "text": "https://doi.org/10.1111/ehr.13019",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": "{/ref} But in the following century \u2013 as the vaccine reached more people and improved over time \u2013 it became rarer and rarer as a cause of death.",
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                ],
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                "type": "text",
                "value": [
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                        "text": "Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication",
                        "children": [
                            {
                                "text": "the lives",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " of around 150 to 200 million people since.",
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                    }
                ],
                "parseErrors": []
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            {
                "url": "https://ourworldindata.org/smallpox",
                "type": "prominent-link",
                "title": "Our research and data on smallpox",
                "description": "We eradicated one of the worst infectious diseases globally.",
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                "type": "text",
                "value": [
                    {
                        "text": "The history of ",
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                    {
                        "children": [
                            {
                                "text": "polio",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-bold"
                    },
                    {
                        "text": " is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient\u2019s breathing muscles.\u00a0",
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                "type": "text",
                "value": [
                    {
                        "text": "The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients\u2019 only chance to survive was to be ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung",
                        "children": [
                            {
                                "text": "confined to a large, mechanical breathing apparatus",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ": the so-called \u2018iron lungs\u2019.\u00a0",
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                "type": "text",
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                        "text": "The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as \u201cmore than a scientific achievement\u201d according to Salk\u2019s biographer Richard Carter.{ref}\u201cRichard Carter (1966) \u2013 Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, \u201cwas a folk victory, an occasion for pride and jubilation\u2026 people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,\u2026 took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.\u201d",
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                "type": "text",
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                    {
                        "text": "As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free.\u00a0",
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region",
                        "children": [
                            {
                                "text": "there were",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "http://polioeradication.org/polio-today/polio-now/this-week",
                        "children": [
                            {
                                "text": "polioeradication.org/polio-today/polio-now/this-week",
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                        ],
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                    },
                    {
                        "text": "\u00a0 {/ref}",
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                    }
                ],
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            {
                "url": "https://ourworldindata.org/polio",
                "type": "prominent-link",
                "title": "Our research and data on polio.",
                "description": "With the help of the vaccine we might be able to eradicate polio globally.",
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                "value": [
                    {
                        "children": [
                            {
                                "text": "Measles",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-bold"
                    },
                    {
                        "text": " too was a major killer for many centuries. The WHO reports: \u201cBefore the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2\u20133 years and measles caused an estimated 2.6 million deaths each year.\u201d{ref}WHO (2019) \u2013 Measles, Key Facts. 5 December 2019. Online here ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.who.int/en/news-room/fact-sheets/detail/measles",
                        "children": [
                            {
                                "text": "https://www.who.int/en/news-room/fact-sheets/detail/measles",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " {/ref}",
                        "spanType": "span-simple-text"
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                ],
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                "type": "text",
                "value": [
                    {
                        "text": "Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) \u2013 the average number of secondary cases arising from each case \u2013 range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., & Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "The Lancet Infectious Diseases",
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                        "text": "The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families.",
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                        "text": "Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox.",
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2020-07-20 15:27:50

2024-02-16 14:22:50

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[
    "Max Roser"
]

For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.

2020-07-20 16:27:50

2022-01-17 14:07:39

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{}

updated version: 21 July 2020 Our World in Data presents the data and research to make progress against the world’s largest problems. This blog post draws on data and research discussed in our entries on **[vaccination](https://ourworldindata.org/vaccination)** and the **[coronavirus pandemic](https://ourworldindata.org/coronavirus)**. For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough. Humanity’s history is a continuous battle between us and the microbes.{ref}An excellent book on the topic is: Dorothy H. Crawford (2009) – Deadly Companions: How microbes shaped our history.{/ref} For most of our history we were on the losing side. It wasn’t even close. We were losing very decisively. Billions of children died from infectious diseases. They were the main reason why child mortality was so high: No matter where or when they were born, around half died as children. We looked at the evidence of child mortality in pre-modern times [here](https://ourworldindata.org/child-mortality-in-the-past). The recurring epidemics of influenza, measles, cholera, diphtheria, the bubonic plague, and smallpox also killed large parts of the adult population. Within just a few years the Black Death killed half of Europe’s population.{ref}See the time-series of the English population [here](https://ourworldindata.org/grapher/population-of-england-millennium). Mortality was similarly high, or even higher, in other parts of Europe. In his history of the Black Death Ole Jørgen Benedictow suggests that 60% of the population of Europe died in that pandemic. [See Benedictow (2004) – The Black Death 1346–1353: The Complete History.]{/ref} The epidemics – especially of smallpox, but also measles, typhus and other diseases – that the colonialists brought from Europe with them to the Americas often killed an even larger share of the population.{ref}See Noble David Cook (1998) – Born to Die: Disease and New World Conquest, 1492-1650. Cambridge University Press.{/ref} The world today is obviously very different. Infectious diseases are the cause of [fewer than 1-in-6 deaths](https://ourworldindata.org/causes-of-death#causes-of-death-by-category), and as the world made progress against the microbes our lives became much longer. The global average life expectancy is now 73 years after life expectancy [doubled in every world region](https://ourworldindata.org/life-expectancy-globally). ### Until recently no one knew where diseases came from How is it possible that for millennia we were losing the battle against the microbes so awfully and then turned things around in the span of just a few generations? Science is the foundation for our success. 150 years ago nobody knew where diseases came from. Or more precisely, people thought they knew, but they were wrong. The widely accepted idea at the time was the ‘Miasma’ theory of disease. Miasma, the theory held, was a form of "bad air" that causes disease. The word _malaria_ is testament to the idea that ‘mal aria’ – ‘bad air’ in medieval Italian – is the cause of the disease. Thanks to the work of a number of doctors and chemists in the second half of the 19th century humanity learned that not noxious air, but specific germs cause infectious diseases. The _germ theory of disease_ was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines. ### Vaccines get your immune system ready for the battle Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease. “The fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,” as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here [moxforum.co.uk/archive/](https://moxforum.co.uk/archive/){/ref} The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body’s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen. ### Public health: You are only safe if everyone else is safe Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection. As is so often the case in development [you cannot achieve progress by yourself](https://ourworldindata.org/global-inequality-of-opportunity). Your progress towards a healthier life depends on everyone else’s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs. Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe – as early as the 17th century – was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. _The Economic History Review_, _73_(3), E1–E19. [https://doi.org/10.1111/ehr.13019](https://doi.org/10.1111/ehr.13019){/ref} Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an [excellent overview](https://rootsofprogress.org/draining-the-swamp) of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century. Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now – in the COVID-19 pandemic – that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this [here](https://ourworldindata.org/identify-covid-exemplars)). ## Infectious diseases before and after the vaccine was introduced How effective were these training sessions against infectious diseases? In the **three charts **I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available. **Smallpox** was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) – Smallpox: The Death of a Disease - The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref} Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very [first vaccine ever](https://ourworldindata.org/smallpox#vaccine-against-smallpox). In England in the mid‐eighteenth century it was probably the leading cause of death.{ref}Shaw‐Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality†. _The Economic History Review_, _73_(3), E1–E19. [https://doi.org/10.1111/ehr.13019](https://doi.org/10.1111/ehr.13019){/ref} But in the following century – as the vaccine reached more people and improved over time – it became rarer and rarer as a cause of death. Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved [the lives](https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication) of around 150 to 200 million people since. ### Our research and data on smallpox We eradicated one of the worst infectious diseases globally. https://ourworldindata.org/smallpox The history of **polio** is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient’s breathing muscles. The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients’ only chance to survive was to be [confined to a large, mechanical breathing apparatus](https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung): the so-called ‘iron lungs’. The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as “more than a scientific achievement” according to Salk’s biographer Richard Carter.{ref}“Richard Carter (1966) – Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, “was a folk victory, an occasion for pride and jubilation… people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,… took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.” As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free. Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s [there were](https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region) between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at [polioeradication.org/polio-today/polio-now/this-week](http://polioeradication.org/polio-today/polio-now/this-week) {/ref} ### Our research and data on polio. With the help of the vaccine we might be able to eradicate polio globally. https://ourworldindata.org/polio **Measles** too was a major killer for many centuries. The WHO reports: “Before the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2–3 years and measles caused an estimated 2.6 million deaths each year.”{ref}WHO (2019) – Measles, Key Facts. 5 December 2019. Online here [https://www.who.int/en/news-room/fact-sheets/detail/measles](https://www.who.int/en/news-room/fact-sheets/detail/measles) {/ref} Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) – the average number of secondary cases arising from each case – range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., & Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. _The Lancet Infectious Diseases_, _17_(12), e420–e428.[ https://doi.org/10.1016/S1473-3099(17)30307-9](https://doi.org/10.1016/S1473-3099(17)30307-9){/ref} The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families. Globally we have also made a lot of progress. Today, 85% of one-year olds [receive](https://ourworldindata.org/grapher/share-of-children-vaccinated-against-measles?tab=chart&time=1983..2017&country=~OWID_WRL) the measles vaccine and the number of deaths has fallen from 2.6 million [to 83,000 in the latest data](https://ourworldindata.org/grapher/deaths-due-to-measles-gbd). Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox. See [https://en.wikipedia.org/wiki/Vaccine-preventable_diseases](https://en.wikipedia.org/wiki/Vaccine-preventable_diseases) and [https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/](https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/){/ref} I selected these three diseases because they protect us from _particularly_ terrible diseases. And the vaccines for polio and measles stand out because even the very early stage prototypes were very efficacious; the efficacy of many other vaccines increased slowly over time as researchers made adjustments that improved them. <Image filename="Vaccination-introduction-and-cases-or-deaths.jpg" alt=""/> ## Science is our best strategy now Some of the best training you ever received were the vaccines you were given in your very early childhood. Without even realizing it, you learned how to battle the pathogens that ravaged the lives of your ancestors for many millennia. When humanity achieves very substantial progress it can become difficult to understand what the problems were that we made progress against. This is also the case for vaccine-preventable diseases. Infectious diseases that once disfigured, pained, paralyzed, and killed many of our ancestors have disappeared so far from our lives and memories that some today can afford the luxury of disregarding or even avoiding vaccination. Today as we face the COVID-19 pandemic, it is the first time for many of us that we experience for one infectious disease what our ancestors experienced for a whole range of them. Just as they were without protection against the diseases discussed previously, we are now facing a pathogen that we have no treatment for and no protection from. And now, just as back then, our best hope is science. The responses from [South Korea](https://ourworldindata.org/covid-exemplar-south-korea), [Vietnam](https://ourworldindata.org/covid-exemplar-vietnam), and [Germany](https://ourworldindata.org/covid-exemplar-germany) show that it is possible to fight the disease successfully, but to end the suffering that COVID-19 causes our best hope is a vaccine against the virus. We were never better equipped to battle a virus. The genome was sequenced within two weeks and since then scientists around the world have been [working tirelessly](https://www.bloomberg.com/news/features/2020-07-15/oxford-s-covid-19-vaccine-is-the-coronavirus-front-runner) to develop the vaccine that brings the pandemic to an end. The [early results](https://www.ox.ac.uk/news/2020-07-20-new-study-reveals-oxford-coronavirus-vaccine-produces-strong-immune-response) from the vaccine developed here at the University of Oxford are promising. Our best strategy in the age-old fight against the germs is our collaborative, data-based effort to study the world around us and within us. Our best strategy is science. …_continue reading on Our World in Data:_ ### Our data and research on the COVID-19 pandemic We currently focus our efforts on the data and research on the COVID-19 pandemic. What does the latest data say? How can we win the battle against COVID-19? https://ourworldindata.org/coronavirus

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        "rendered": "\n<div class=\"blog-info\">\n<p>updated version: 21 July 2020</p>\n<p>Our World in Data presents the data and research to make progress against the world\u2019s largest problems.<br>This blog post draws on data and research discussed in our entries on <strong><a href=\"https://ourworldindata.org/vaccination\" target=\"_blank\" rel=\"noopener noreferrer\">vaccination</a></strong> and the <strong><a href=\"https://ourworldindata.org/coronavirus\" target=\"_blank\" rel=\"noopener noreferrer\">coronavirus pandemic</a></strong>.</p>\n<p>For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.</p>\n</div>\n\n\n\n<p>Humanity\u2019s history is a continuous battle between us and the microbes.{ref}An excellent book on the topic is: Dorothy H. Crawford&nbsp; (2009) \u2013 Deadly Companions: How microbes shaped our history.{/ref} For most of our history we were on the losing side.</p>\n\n\n\n<p>It wasn\u2019t even close. We were losing very decisively. Billions of children died from infectious diseases. They were the main reason why child mortality was so high: No matter where or when they were born, around half died as children. We looked at the evidence of child mortality in pre-modern times <a href=\"https://ourworldindata.org/child-mortality-in-the-past\">here</a>.&nbsp;</p>\n\n\n\n<p>The recurring epidemics of influenza, measles, cholera, diphtheria, the bubonic plague, and smallpox also killed large parts of the adult population. Within just a few years the Black Death killed half of Europe\u2019s population.{ref}See the time-series of the English population <a href=\"https://ourworldindata.org/grapher/population-of-england-millennium\">here</a>.<br>Mortality was similarly high, or even higher, in other parts of Europe.</p>\n\n\n\n<p>In his history of the Black Death Ole J\u00f8rgen Benedictow suggests that 60% of the population of Europe died in that pandemic. [See Benedictow (2004) \u2013 The Black Death 1346\u20131353: The Complete History.]{/ref} The epidemics \u2013 especially of smallpox, but also measles, typhus and other diseases \u2013 that the colonialists brought from Europe with them to the Americas often killed an even larger share of the population.{ref}See Noble David Cook (1998) \u2013 Born to Die: Disease and New World Conquest, 1492-1650. Cambridge University Press.{/ref}</p>\n\n\n\n<p>The world today is obviously very different. Infectious diseases are the cause of <a href=\"https://ourworldindata.org/causes-of-death#causes-of-death-by-category\">fewer than 1-in-6 deaths</a>, and as the world made progress against the microbes our lives became much longer. The global average life expectancy is now 73 years after life expectancy <a href=\"https://ourworldindata.org/life-expectancy-globally\">doubled in every world region</a>.</p>\n\n\n\n<h5>Until recently no one knew where diseases came from</h5>\n\n\n\n<p>How is it possible that for millennia we were losing the battle against the microbes so awfully and then turned things around in the span of just a few generations?</p>\n\n\n\n<p>Science is the foundation for our success. 150 years ago nobody knew where diseases came from. Or more precisely, people thought they knew, but they were wrong.&nbsp;The widely accepted idea at the time was the \u2018Miasma\u2019 theory of disease. Miasma, the theory held, was a form of &#8220;bad air&#8221; that causes disease. The word <em>malaria</em> is testament to the idea that \u2018mal aria\u2019 \u2013 \u2018bad air\u2019 in medieval Italian \u2013 is the cause of the disease.</p>\n\n\n\n<p>Thanks to the work of a number of doctors and chemists in the second half of the 19th century humanity learned that not noxious air, but specific germs cause infectious diseases. The <em>germ theory of disease</em> was the breakthrough in the fight against the microbe. Scientists identified the pathogens that cause the different diseases and thereby laid the foundation for perhaps the most important technical innovation in our fight against them: vaccines.&nbsp;</p>\n\n\n\n<h5>Vaccines get your immune system ready for the battle</h5>\n\n\n\n<p>Vaccines protect us from infectious diseases by offering our body a training session for how to fight the germs that cause the disease.&nbsp;\u201cThe fundamental idea of a vaccine is deliberate exposure to a relatively harmless or dead version of a germ. The immune system will then recognise and eliminate that germ rapidly if it is encountered again,\u201d as vaccine developer Richard Moxon puts it.{ref}See the archive of Moxon here <a href=\"https://moxforum.co.uk/archive/\">moxforum.co.uk/archive/</a>{/ref}</p>\n\n\n\n<p>The trick is that the ineffective form of the pathogen is not causing the disease, but resembles the effective pathogen so much that it triggers our body\u2019s natural immune system to produce the antibodies that destroy that pathogen. The training session that it provides to the body means our immune system will recognize the invader once we become infected with the real pathogen later in life. Our immune system can quickly muster up what it learnt from the vaccine response, and immediately start fighting the pathogen.</p>\n\n\n\n<h5>Public health: You are only safe if everyone else is safe</h5>\n\n\n\n<p>Vaccines not only protect the health of the immunized person but also the health of the community. If vaccination rates are high enough the transmission of infectious diseases is interrupted in the community which means that even those who are unvaccinated gain protection.</p>\n\n\n\n<p>As is so often the case in development <a href=\"https://ourworldindata.org/global-inequality-of-opportunity\">you cannot achieve progress by yourself</a>. Your progress towards a healthier life depends on everyone else\u2019s progress towards a healthier life; you safer if others are vaccinated too. The health improvements that you cannot achieve by yourself is the sphere of public health and many of the most important interventions in the fight against infectious diseases were therefore financed socially. Public spending financed the crucial improvements in sanitation as well as many large vaccination programs.</p>\n\n\n\n<p>Vaccination programs are one of many strategies by which we made progress against infectious diseases. The first pathogen successively defeated by humans in Europe \u2013 as early as the 17th century \u2013 was the plague. According to Shaw-Taylor (2020) this was achieved by a combination of quarantine measures, cordons sanitaire and contact tracing (which was first developed in the Renaissance).{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality. <em>The Economic History Review</em>, <em>73</em>(3), E1\u2013E19. <a href=\"https://doi.org/10.1111/ehr.13019\">https://doi.org/10.1111/ehr.13019</a>{/ref} </p>\n\n\n\n<p>Since then we found many additional strategies against the various microbes. Antibiotics, safe drinking water, better housing, better education, falling poverty, declining undernourishment, pasteurization, hygiene, better sanitation and other public health advancements were and are crucial. Jason Crawford provides an <a href=\"https://rootsofprogress.org/draining-the-swamp\">excellent overview</a> of the crucial role of better sanitation, hygiene, and other public health measures for the progress since the 19th century.</p>\n\n\n\n<p>Today too, vaccines are only one of many strategies that we have found in the battle against the microbes. We see now \u2013 in the COVID-19 pandemic \u2013 that there are several countries responding successfully to the virus without the help of a vaccine (we studied how they do this <a href=\"https://ourworldindata.org/identify-covid-exemplars\">here</a>).&nbsp;</p>\n\n\n\n<h4>Infectious diseases before and after the vaccine was introduced</h4>\n\n\n\n<p>How effective were these training sessions against infectious diseases?</p>\n\n\n\n<p>In the <strong>three charts </strong>I plotted the evolution of three infectious diseases over several decades. You see the data before and after the first vaccination became available.</p>\n\n\n\n<p><strong>Smallpox</strong> was one of the worst killers in our history. Epidemiologist Donald Henderson suggests that in the last hundred years of its existence smallpox killed at least half a billion people.{ref}D. A. Henderson (2009) \u2013 Smallpox: The Death of a Disease &#8211; The Inside Story of Eradicating a Worldwide Killer. Published by Prometheus Books.{/ref}&nbsp;Even more people were disfigured by the disease for the rest of their lives.{ref}The Wikipedia entry on smallpox includes several photos of smallpox survivors. On Google you find more.{/ref} Despite all efforts, humanity never found an effective treatment. But we invented something even better: a vaccine, the very <a href=\"https://ourworldindata.org/smallpox#vaccine-against-smallpox\">first vaccine ever</a>.</p>\n\n\n\n<p>In England in the mid\u2010eighteenth century it was probably the leading cause of death.{ref}Shaw\u2010Taylor, L. (2020). An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality\u2020. <em>The Economic History Review</em>, <em>73</em>(3), E1\u2013E19. <a href=\"https://doi.org/10.1111/ehr.13019\">https://doi.org/10.1111/ehr.13019</a>{/ref} But in the following century \u2013 as the vaccine reached more people and improved over time \u2013 it became rarer and rarer as a cause of death.</p>\n\n\n\n<p>Eventually the disease was eliminated in entire countries, then entire continents, and today the disease does not exist anywhere in the world. The smallpox vaccine made it possible to completely eradicate the disease. Its eradication has saved <a href=\"https://ourworldindata.org/smallpox#lives-saved-from-smallpox-eradication\">the lives</a> of around 150 to 200 million people since.</p>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/smallpox</link-url>\n        <title>Our research and data on smallpox</title>\n        <content>\n\n<p>We eradicated one of the worst infectious diseases globally.</p>\n\n</content>\n        <figure><img width=\"768\" height=\"542\" src=\"https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-768x542.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-768x542.png 768w, https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-150x106.png 150w, https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-400x282.png 400w, https://owid.cloud/app/uploads/2018/07/decade-in-which-smallpox-ceased-to-be-endemic-by-country-750x529.png 750w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n    </block>\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<p>The history of <strong>polio</strong> is similar, but more recent. Polio epidemics spread panic at a time that many today can still remember. Polio is an infectious disease, contracted predominantly by children, that can lead to the permanent paralysis of various body parts. Ultimately it can cause death by immobilizing the patient\u2019s breathing muscles.&nbsp;</p>\n\n\n\n<p>The chart shows data from the US, the country where the first vaccine was developed and used. In the first half of the last century the US suffered large outbreaks with many tens of thousands paralyzed. Patients\u2019 only chance to survive was to be <a href=\"https://ourworldindata.org/polio#fighting-polio-s-symptoms-the-iron-lung\">confined to a large, mechanical breathing apparatus</a>: the so-called \u2018iron lungs\u2019.&nbsp;</p>\n\n\n\n<p>The recurring outbreaks ended in 1955 when Jonas Salk finally developed the polio vaccine. When it was announced on April 12 it was celebrated as \u201cmore than a scientific achievement\u201d according to Salk\u2019s biographer Richard Carter.{ref}\u201cRichard Carter (1966) \u2013 Breakthrough: The saga of Jonas Salk. Trident Press.{/ref}. The vaccine, he writes, \u201cwas a folk victory, an occasion for pride and jubilation\u2026 people observed moments of silence, rang bells, honked horns, blew factory whistles, fired salutes,\u2026 took the rest of the day off, closed their schools or convoked fervid assemblies therein, drank toasts, hugged children, attended church, smiled at strangers, and forgave enemies.\u201d</p>\n\n\n\n<p>As the chart shows, these celebrations were not misplaced. Over the coming years vaccination campaigns reached many American children and the terrible epidemics ended. By 1979 the US was declared polio-free.&nbsp;</p>\n\n\n\n<p>Today our generation has the chance to achieve for polio what has been achieved for smallpox: eradicate it completely. Thanks to the vaccine, humanity has made massive progress towards this goal. In the early 1980s <a href=\"https://ourworldindata.org/grapher/number-of-estimated-paralytic-polio-cases-by-world-region\">there were</a> between three- and four-hundred-thousand paralytic cases every year. In the last 12 months (as the time of writing) there were 298 polio cases globally.{ref}The latest statistics on polio cases globally can always be found at <a href=\"http://polioeradication.org/polio-today/polio-now/this-week\">polioeradication.org/polio-today/polio-now/this-week</a>&nbsp; {/ref}</p>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/polio</link-url>\n        <title>Our research and data on polio.</title>\n        <content>\n\n<p>With the help of the vaccine we might be able to eradicate polio globally.</p>\n\n</content>\n        <figure><img width=\"768\" height=\"542\" src=\"https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-768x542.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-768x542.png 768w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-150x106.png 150w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-400x282.png 400w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region-750x529.png 750w, https://owid.cloud/app/uploads/2017/10/the-number-of-reported-polio-cases-by-world-region.png 2040w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n    </block>\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<p><strong>Measles</strong> too was a major killer for many centuries. The WHO reports: \u201cBefore the introduction of the measles vaccine in 1963 and widespread vaccination, major epidemics occurred approximately every 2\u20133 years and measles caused an estimated 2.6 million deaths each year.\u201d{ref}WHO (2019) \u2013 Measles, Key Facts. 5 December 2019. Online here <a href=\"https://www.who.int/en/news-room/fact-sheets/detail/measles\">https://www.who.int/en/news-room/fact-sheets/detail/measles</a> {/ref}</p>\n\n\n\n<p>Measles is both very deadly and extremely contagious. Published estimates of the basic reproduction number (R0) \u2013 the average number of secondary cases arising from each case \u2013 range from 3.7 up to 203.{ref}Guerra, F. M., Bolotin, S., Lim, G., Heffernan, J., Deeks, S. L., Li, Y., &amp; Crowcroft, N. S. (2017). The basic reproduction number (R0) of measles: A systematic review. <em>The Lancet Infectious Diseases</em>, <em>17</em>(12), e420\u2013e428.<a href=\"https://doi.org/10.1016/S1473-3099(17)30307-9\"> https://doi.org/10.1016/S1473-3099(17)30307-9</a>{/ref}</p>\n\n\n\n<p>The chart shows how rapidly we made progress against this killer after the invention of the vaccine. Once it was introduced in the US, the large outbreaks of the airborne disease came to an end. The measles vaccine too changed world history and the history of millions of families.</p>\n\n\n\n<p>Globally we have also made a lot of progress. Today, 85% of one-year olds <a href=\"https://ourworldindata.org/grapher/share-of-children-vaccinated-against-measles?tab=chart&amp;time=1983..2017&amp;country=~OWID_WRL\">receive</a> the measles vaccine and the number of deaths has fallen from 2.6 million <a href=\"https://ourworldindata.org/grapher/deaths-due-to-measles-gbd\">to 83,000 in the latest data</a>.\u00a0</p>\n\n\n\n<p>Smallpox, polio, and measles are just three of the diseases we have vaccines for. We now have effective vaccines against at least 28 diseases.{ref}Cholera, Dengue fever, Diphtheria, Haemophilus influenzae type b, Hepatitis A, Hepatitis B, Hepatitis E, Human papilloma-virus, Influenza, Japanese encephalitis, Malaria, Measles, Meningococcal disease, Mumps, Pneumococcal disease, Pertussis, Poliomyelitis, Rabies, Rotavirus gastroenteritis, Rubella, Tetanus, Tick-borne encephalitis, Tuberculosis, Typhoid fever, Varicella, Yellow fever, Shingles (Herpes Zoster), and Smallpox.<br>See <a href=\"https://en.wikipedia.org/wiki/Vaccine-preventable_diseases\">https://en.wikipedia.org/wiki/Vaccine-preventable_diseases</a> and <a href=\"https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/\">https://www.who.int/immunization/global_vaccine_action_plan/GVAP_doc_2011_2020/en/</a>{/ref}<br>I selected these three diseases because they protect us from <em>particularly</em> terrible diseases. And the vaccines for polio and measles stand out because even the very early stage prototypes were very efficacious; the efficacy of many other vaccines increased slowly over time as researchers made adjustments that improved them.</p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" width=\"1403\" height=\"1966\" src=\"https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths.jpg\" alt=\"\" class=\"wp-image-39984\" srcset=\"https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths.jpg 1403w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-285x400.jpg 285w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-392x550.jpg 392w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-107x150.jpg 107w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-768x1076.jpg 768w, https://owid.cloud/app/uploads/2021/02/Vaccination-introduction-and-cases-or-deaths-1096x1536.jpg 1096w\" sizes=\"(max-width: 1403px) 100vw, 1403px\" /></figure>\n\n\n\n<h4>Science is our best strategy now</h4>\n\n\n\n<p>Some of the best training you ever received were the vaccines you were given in your very early childhood. Without even realizing it, you learned how to battle the pathogens that ravaged the lives of your ancestors for many millennia.</p>\n\n\n\n<p>When humanity achieves very substantial progress it can become difficult to understand what the problems were that we made progress against. This is also the case for vaccine-preventable diseases. Infectious diseases that once disfigured, pained, paralyzed, and killed many of our ancestors have disappeared so far from our lives and memories that some today can afford the luxury of disregarding or even avoiding vaccination.</p>\n\n\n\n<p>Today as we face the COVID-19 pandemic, it is the first time for many of us that we experience for one infectious disease what our ancestors experienced for a whole range of them. Just as they were without protection against the diseases discussed previously, we are now facing a pathogen that we have no treatment for and no protection from.&nbsp;</p>\n\n\n\n<p>And now, just as back then, our best hope is science. The responses from <a href=\"https://ourworldindata.org/covid-exemplar-south-korea\">South Korea</a>, <a href=\"https://ourworldindata.org/covid-exemplar-vietnam\">Vietnam</a>, and <a href=\"https://ourworldindata.org/covid-exemplar-germany\">Germany</a> show that it is possible to fight the disease successfully, but to end the suffering that COVID-19 causes our best hope is a vaccine against the virus.&nbsp;</p>\n\n\n\n<p>We were never better equipped to battle a virus. The genome was sequenced within two weeks and since then scientists around the world have been <a href=\"https://www.bloomberg.com/news/features/2020-07-15/oxford-s-covid-19-vaccine-is-the-coronavirus-front-runner\">working tirelessly</a> to develop the vaccine that brings the pandemic to an end. The <a href=\"https://www.ox.ac.uk/news/2020-07-20-new-study-reveals-oxford-coronavirus-vaccine-produces-strong-immune-response\">early results</a> from the vaccine developed here at the University of Oxford are promising.</p>\n\n\n\n<p>Our best strategy in the age-old fight against the germs is our collaborative, data-based effort to study the world around us and within us. Our best strategy is science.</p>\n\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<p>\u2026<em>continue reading on Our World in Data:</em></p>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/coronavirus</link-url>\n        <title>Our data and research on the COVID-19 pandemic</title>\n        <content>\n\n<p>We currently focus our efforts on the data and research on the COVID-19 pandemic. What does the latest data say? How can we win the battle against COVID-19?</p>\n\n</content>\n        <figure><img width=\"768\" height=\"463\" src=\"https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-768x463.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-768x463.png 768w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-400x241.png 400w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-800x482.png 800w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-150x90.png 150w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18-1536x926.png 1536w, https://owid.cloud/app/uploads/2020/06/Screen-Shot-2020-06-29-at-14.16.18.png 1914w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n    </block>\n\n\n<p></p>\n",
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    "excerpt": {
        "rendered": "For most of our history we were losing terribly against the microbes. Only recently did we turn the battle in our favour. Vaccines were a major breakthrough.",
        "protected": false
    },
    "date_gmt": "2020-07-20T15:27:50",
    "modified": "2022-01-17T14:07:39",
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    "ping_status": "closed",
    "authors_name": [
        "Max Roser"
    ],
    "modified_gmt": "2022-01-17T14:07:39",
    "comment_status": "closed",
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