Expected adverse events in a mass smallpox vaccination campaign.

Abstract

The decision to resume smallpox vaccination depends on weighing the likelihood of a smallpox attack and its anticipated mortality against expected harm from a mass immunization program. Smallpox vaccine has a higher complication rate than any other vaccine currently being used. Careful prevaccination exclusion of high-risk individuals and their close contacts would be essential to minimize complications of a mass vaccination campaign, although such exclusions necessarily mean that some proportion of the population will remain susceptible to smallpox.