Smallpox was the first widespread disease to be eliminated by human invention . In May, 1966, the World Health Organization (WHO) , an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox . The goal was to eliminate the disease in one decade . At the time , the disease posed a serious threat to people in more than thirty nations . Because similar projects for malaria and yellow fever had failed , few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign no cases were reported in the field 

The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission . Rewards for reporting smallpox assisted in motivating removed from contact with others and treated . at the same time , the entire village where the victim had lived was vaccinated

By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for two additional years to be completely sure . In may , 1980, a formal statement was made to the global community . Today smallpox is no longer a threat to humanity . Routine vaccinations have been stopped worldwide.