Ali Maow Maalin, the last natural case of smallpox, develops a rash in Somalia. The WHO and the CDC consider this date to be the anniversary of the eradication of smallpox, the most spectacular success of vaccination.

Ali Maow Maalin was a Somali hospital cook and health worker from Merca who is the last person known to have been infected with naturally occurring Variola minor smallpox. The disease was diagnosed in October 1977 and Maalin made a full recovery. Although he had many contacts, none of them developed the disease, and an aggressive containment campaign was successful in preventing an outbreak. Smallpox was declared to have been eradicated globally by the World Health Organization (WHO) two years later. Maalin was subsequently involved in the successful poliomyelitis eradication campaign in Somalia, and he died of malaria while carrying out polio vaccinations after the re-emergence of the poliovirus in 2013.