EA - Smallpox eradication by Lizka

Link to original articleWelcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Smallpox eradication, published by Lizka on December 9, 2022 on The Effective Altruism Forum.Today (December 9) is Smallpox Eradication Day. 43 years ago, smallpox was confirmed to have been eradicated after killing hundreds of millions of people. This was a major achievement in global health.So I'm link-posting Our World in Data’s data explorer on smallpox (and here’s the section on how decline & eradication was achieved).This post shares a summary of the history of the eradication of smallpox and selected excerpts from the data explorer.A summary of the history of smallpox eradicationSmallpox was extremely deadly, probably killing 300 million people in the 20th century alone. The last known cases occurred in 1977, and smallpox is now the only human disease that has been completely eradicated.So how was this accomplished?Before we had a smallpox vaccine, we had the practice of variolation — deliberately exposing people to material from smallpox scabs or pus, in order to protect them against the disease (variolation traces back to 16th century China). While variolation made cases of smallpox much less severe, variolation infected the patient and could spread the disease to others, and the severity of the infection could not be easily controlled. So variolation did not lead to the elimination of smallpox from the population.In the late 18th century, Edward Jenner demonstrated that exposure to cowpox — a much less severe disease that turns out to be related — protected people against smallpox. This, in turn, led to the invention of a vaccine against smallpox (the first vaccine ever).In the 19th and 20th centuries, further improvements were made to the smallpox vaccine, and many states were running programs to vaccinate significant portions of the population. By 1959, the World Health Organization (WHO) launched a global program to eradicate smallpox . This involved a coordinated effort to immunize large numbers of people, isolate infected individuals, and monitor the spread of the disease. The program used a technique known as ring vaccination, which involved vaccinating people who had been in contact with infected individuals, in order to create a protective "ring" around the infected person and prevent further spread of the disease.Excerpts from the Our World in Data entryIntroductionSmallpox is the only human disease that has been successfully eradicated.Smallpox, an infectious disease caused by the variola virus, was a major cause of mortality in the past, with historic records of outbreaks across the world. Its historic death tolls were so large that it is often likened to the Black Plague.The eradication of smallpox is therefore a major success story for global health for several reasons: it was a disease that was endemic (and caused high mortality rates) across all continents; but was also crucial to advances in the field of immunology. The smallpox vaccine was the first successful vaccine to be developed.How many died of smallpox?In his review paper ‘The eradication of smallpox – An overview of the past, present, and future’ Donald Henderson reports that during the 20th century alone “an estimated 300 million people died of the disease.”In his book Anderson suggests that in the last hundred years of its existence smallpox killed “at least half a billion people.” 500 million deaths over a century means 5 million annual deaths on average.Eradication across the worldThe last variola major infection was recorded in Bangladesh in October 1975, and the last variola minor infection occurred two years later in Merka, Somalia, on October 26th, 1977. During the following two years, WHO teams searched the African continent for further smallpox cases among those rash-like symptoms (which is a symptom of numerous other diseases). They found no further cas...