Smallpox

Smallpox is an acute contagious disease caused by the variola virus, a member of the orthopoxvirus family. It was one of the most devastating diseases known to humanity and caused millions of deaths before it was eradicated. It is believed to have existed for at least 3000 years.  

The smallpox vaccine, created by Edward Jenner in 1796, was the first successful vaccine to be developed. He observed that milkmaids who previously had caught cowpox did not catch smallpox and showed that a similar inoculation could be used to prevent smallpox in other people.

Early symptoms of smallpox include high fever, fatigue and severe back pain, and less often, abdominal pain and vomiting. Two to 3 days later the virus produces a characteristic rash with bumps full of a clear liquid, which later fill with pus and finally develop a crust that dries and falls off. The rash begins on the face and hands, then spreads to the rest of the body. Lesions develop in the mucous membranes of the nose and mouth and ulcerate soon after formation.

The period since eradication has been defined by a lengthy and complex debate focussed on the destruction of the last remaining stocks of live variola virus. In 1996, at the 49th World Health Assembly, Member States decided to have this stock destroyed in June 1999, and only to allow small samples to be kept for research purposes at two designated secure laboratories – one in the United States and one in the Russian Federation.