The eradication of smallpox in Shanghai, China, October 1950-July 1951

Smallpox (variola major) was endemic in China for thousands of years until it was finally eradicated from the country in the early 1960s. The strategy and tactics of the eradication campaign in Shanghai, the largest city and major communications centre in China, were typical of those employed throughout China, but had some additional features of interest.The decision to eradicate smallpox was made in 1950 and three preparatory steps were taken immediately: supplies of potent (liquid) vaccine were assured; popular support was enlisted by intensive propaganda; and teams of vaccinators were trained. In Shanghai, the mass vaccination campaign began in October 1950, at a time when a smallpox epidemic was raging in the city. The last case of smallpox in the city was recorded in July 1951. A special feature of the campaign in Shanghai was the introduction of a national vaccination certificate to prevent export of smallpox from the city by the 2 800 000 persons who moved in and out of Shanghai each week by rail, bus, or boat.Eradication was followed up by a programme of vaccination of all infants, with revaccination at 6, 12, and 18 years of age, and mass vaccination campaigns in 1963, 1968, 1972, and 1978. The number of adverse reactions to vaccination was small and fell progressively from an overall figure of 8.4 per 100 000 in 1963 to 2.5 per 100 000 in 1978. Vaccination requirements were relaxed in 1978, but smallpox vaccination is still offered to children as part of the immunization programme.