Update: adverse events following civilian smallpox vaccination--United States, 2003.

During January 24-December 31, 2003, smallpox vaccine was administered to 39,213 civilian health-care and public health workers in 55 jurisdictions to prepare the United States for a possible terrorist attack using smallpox virus. This report updates information on vaccine-associated adverse events among civilians vaccinated since the beginning of the program and among contacts of vaccinees, received by CDC from the Vaccine Adverse Event Reporting System (VAERS) during August 9-December 31.