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

During January 24-June 20, 2003, smallpox vaccine was administered to 37,802 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) as of June 20. Two cases of dilated cardiomyopathy (DCM) were diagnosed 3 months after vaccination. For the potential relation between smallpox vaccine and DCM to be assessed, identification of additional cases of DCM among vaccinees will be essential. Physicians who treat smallpox vaccine recipients are encouraged to evaluate and report patients with symptoms compatible with DCM, including those that occur several months after vaccination.