Smallpox Eradication
The only human disease ever deliberately eradicated. It is also the only one on this repo whose file is closed and whose tail is still moving. The World Health Assembly asked for eradication in 1959 and almost nothing happened for eight years. [3] The programme that worked ran from 1967, and the thing that made it work was not the thing it was designed around. [1] [3]
Status
solved. The last naturally acquired case was in October 1977 and the disease has not returned. [19] What is unfinished is not the disease. It is the virus, which was never destroyed, and the population immunity, which was allowed to lapse on purpose and is now being tested by something else.
Declared eradicated by the Thirty-third World Health Assembly on 8 May 1980. [5]
The Problem
Smallpox killed at least one in three of the people it infected, and more in its severest forms. [7] It had no animal reservoir, which is the fact the whole eradication effort rests on: a disease that lives only in people can in principle be cornered, because every chain of transmission runs through a human being you could in principle find. [2] In 1967, when the intensified programme began, an estimated 10 to 15 million people were being infected every year. The reported figure for that year was 132,000. [19] The gap between those two numbers is not a footnote. It is the reason the first strategy could not have worked and the second one could.
Key Numbers
The figures this slate rests on. Each has a value, a unit, a year and a source. Correcting one of these is the smallest and most welcome contribution you can make.
Years between the 1959 resolution and real progress [3]
8 yr
Estimated infections per year, 1967 [19]
10-15 M
Cases actually reported that year [19]
132 K
Cost of the intensified programme, 1967 to 1977 [7]
$300 M
Share of that cost paid by the endemic countries [7]
two thirds
Laboratories known to hold variola at eradication, 1980 [2]
6
Laboratories authorised to hold it today [8]
2
Years since the first agreed destruction deadline passed [10]
27 yr
Reported mpox cases, 1970s versus 2010 to 2019 [17]
48 to 18 K
Reported DNA cost of building a related poxvirus, 2017 [20]
$100 K
The last two numbers are the reason this slate is not a victory lap. Eradication removed the disease from circulation. It did not remove the virus from the world, and it did not remove the ability to rebuild one.
How To Read This Slate
Eight pages, the same eight every slate here has. The timeline is the shape of what happened. What worked and what failed carry the interventions, one per chip, each with its evidence. Forks in the road is where the decisions are, and it is the page to read if you only read one. How we know covers the measurement, including the part where nobody could see most of the cases. Still open is what is left.