This paper describes the strategy and execution of the Smallpox Eradication Program in Sierra Leone, a West African country that experienced the highest incidence of this disease in the world in 1967 and in 1968. Five teams vaccinated an average of 1,000 persons per team per day at “collecting points” within 2 to 3 miles of every village, beginning in the most highly endemic areas. Average vaccination coverage rate in mass vaccinated areas was about 80%. An advance team informed villagers of the time and place for vaccination, and an assessment team constantly monitored take rates and vaccination coverage. The surveillance system was rapidly stimulated to improve smallpox reporting by a monthly newsletter. An intensive investigation-control program emphasized the detection of source and extent of smallpox outbreaks and vaccination of infected villages. Nine outbreaks of smallpox occurred in vaccinated areas, with an average of 3.4 cases per outbreak. Seven of the 13 districts were freed of smallpox by outbreak-control measures before they were mass vaccinated. Smallpox transmission was interrupted in April 1969, when only 69% of the total country population had been mass vaccinated and only 15 months after the Smallpox Eradication Program began. The program was jointly sponsored by the United States Agency for International Development, the Government of Sierra Leone, and the World Health Organization.
Present address: Department of Pediatrics, University of Chicago, Chicago, Illinois 60637.
Present address: State and Community Services Division, Center for Disease Control, Atlanta, Georgia 30333.
Present address: Deputy Chief Medical Officer, Ministry of Health, Freetown, Sierra Leone.
Present address: Operations Officer, Smallpox Eradication Program, Center for Disease Control.
Present address: Director, State and Community Services Division, Center for Disease Control, Atlanta, Georgia 30333.