Smallpox was a serious disease caused by the variola virus. It was very contagious and used to kill millions of people worldwide before the World Health Organization (WHO) began an international immunisation campaign. The WHO announced that smallpox had been eradicated in 1979 — the only infectious disease to have been completely wiped out worldwide. The last case in Australia occurred in 1938, while the last reported case anywhere in the word was in Somalia in 1977. After the disease was officially eradicated, all remaining stocks of the virus worldwide were destroyed apart from small amounts held in 2 secure laboratories in the United States and the Russian Federation. No-one is at risk of catching smallpox in Australia today. The only risk would be if the smallpox virus was used in an act of bioterrorism.