Beyond the map
How smallpox disappeared from the map
Smallpox is the only human disease ever eradicated. In 1967, WHO estimated 10 to 15 million cases a year in more than 30 countries where it was still endemic. Ten years later the last natural case was found in a hospital cook in Somalia. It is the most dramatic change any disease map has seen.
This disease is not yet a layer on the map. The article relies on the published sources listed below.
A disease that was everywhere
For centuries smallpox was found on every inhabited continent. It killed about three in ten of those infected with its severe form, and it left many survivors scarred or blind. Estimates of its twentieth-century death toll run to hundreds of millions.
Vaccination shrinks the map
Edward Jenner’s cowpox vaccine of 1796 gave countries the means to fight back, but eliminating the disease took until the twentieth century. By the early 1950s Europe and North America were largely free of endemic smallpox. The United States recorded its last case in 1949. By the 1960s the disease was concentrated in South Asia, Indonesia, sub-Saharan Africa and Brazil.
1967: the intensified campaign
The World Health Assembly first called for eradication in 1959, but progress was slow. In 1967 WHO launched an intensified programme with freeze-dried vaccine that kept in tropical heat. The key innovation was surveillance and containment: instead of trying to vaccinate everyone, teams found each outbreak and vaccinated the contacts around it, sealing it off.
The last places on the map
The map shrank quickly. South America’s last endemic cases were in Brazil in 1971 and Indonesia’s in 1972. In South Asia, where the disease was most entrenched, the last case of severe variola major was a young girl in Bangladesh in 1975. The Horn of Africa came last. Ali Maow Maalin, a hospital cook in Merca, Somalia, fell ill in October 1977 and was the last person to catch smallpox naturally.
A laboratory infection in Birmingham, England, in 1978 caused the last known death. On 8 May 1980 the World Health Assembly declared the world free of smallpox.
Why smallpox could be eradicated
Smallpox had features that most diseases lack. It had no animal reservoir. Its rash made nearly every case visible. People who recovered were immune, and the vaccine was cheap, stable and protective after one dose. Compare polio, where most infections cause no symptoms, or measles, which spreads far more easily.
Common questions
When was smallpox eradicated?
The World Health Assembly declared it eradicated on 8 May 1980. The last natural case was in Somalia in October 1977.
Who was the last person to have smallpox?
Ali Maow Maalin in Merca, Somalia, in 1977 was the last natural case. In 1978 a laboratory-acquired infection in Birmingham, England, caused the last known death.
Does the smallpox virus still exist?
Stocks are kept in two WHO-authorized laboratories, in the United States and Russia.
Is smallpox on the Diseases Map?
Not yet. WHO’s historical smallpox tables are a candidate for a future layer.