The confirmation and maintenance of smallpox eradication.

In December 1979, an independent scientific commission certified global eradication of smallpox. This conclusion was accepted at the 33d World Health Assembly of the World Health Organization (WHO) in May 1980. After WHO's intensified eradication program began in 1967, special certification procedures were used in 35 countries where the disease had been endemic and in 44 others at special risk. Six laboratories are known to retain variola virus; efforts have been made to ensure strict containment of these strains. There is no evidence that smallpox will recur as an endemic disease. Nevertheless, WHO will promote surveillance of smallpox-like disease and selected laboratory research on certain orthopoxviruses. These efforts will maintain confidence that smallpox has been eradicated and confirm that there are no animal reservoirs of variola virus. A more complete understanding of the orthopoxviruses, including monkeypox virus, should also be obtained.