The global eradication of smallpox.

On May 8, 1980, the 33rd World Health Assembly declared the world free of smallpox. This followed approximately 2 1/2 years after the last documented naturally occurring case of smallpox was diagnosed in a hospital worker in Merca, Somalia. A major breakthrough for the eventual control of this disease was the discovery of an effective vaccine by Edward Jenner in 1796. In 1966 the World Health Assembly voted a special budget to eliminate smallpox from the world. At that time, smallpox was endemic in more than 30 countries. Mass vaccination programs were successful in many Western countries; however, a different approach was taken in developing countries. This approach was known as surveillance and containment. Surveillance was aided by extensive house-to-house searches and rewards offered for persons reporting smallpox cases. Containment measures included ring vaccination and isolation of cases and contacts. Hospitals played a major role in transmission in a number of smallpox outbreaks. The World Health Organization is currently supporting several control programs and has not singled out another disease for eradication. The lessons learned from the smallpox campaign can be readily applied to other public health programs.