Smallpox is still the only human disease ever eradicated
Smallpox killed 300 million people in the 20th century before it was wiped out in 1980. Here is why no human disease has followed it.
Smallpox is the only human disease ever eradicated: a global commission certified it gone on 9 December 1979, and the World Health Assembly declared the world free of it on 8 May 1980. It had plagued humanity for at least 3,000 years and killed an estimated 300 million people in the 20th century alone.
“The world and all its peoples have won freedom from smallpox,” the Assembly declared.
WHO’s intensified campaign, launched in 1967, combined case surveillance with mass vaccination. In 1975, three-year-old Rahima Banu of Bangladesh was the last person to catch the deadlier variola major naturally; in 1977, hospital cook Ali Maow Maalin in Somalia became the last natural case of any kind, and recovered. The final death came from a laboratory: in 1978 medical photographer Janet Parker caught the virus at Birmingham University Medical School and died. Today only the CDC in Atlanta and Russia’s VECTOR institute may hold live virus.
No second human disease has followed, because smallpox had a weakness later targets lack: it spread only from person to person, so once every human chain of infection was broken it had nowhere left to hide. Rinderpest, a cattle plague whose last case was in 2001, became the second infectious disease ever eradicated, but it infects animals, not people.
The closest human candidate is guinea worm disease. Cases fell by more than 99%, from an estimated 3.5 million in 1986 to just 15 in 2024. But the same year brought 664 animal infections, most of them in dogs in Cameroon and Chad, which keep the parasite in circulation. Together with insecurity in Mali, South Sudan and Sudan, they threaten any near-term finish.
Four decades on, smallpox remains a one-off.
Sources & references
5 referencesWell-established. Corroborated by 5 independent sources.
