ABSTRACT
BACKGROUND: During the winter of 2002-2003, the Israeli health authorities launched a campaign to vaccinate first responders against smallpox. METHODS: In an open study, 159 healthy, preimmunized adults, 24-52 years old, who participated in the campaign were vaccinated with the Lister strain of vaccinia virus by the multipuncture technique. The safety, immunogenicity, and reactogenicity of the vaccine were assessed. RESULTS: Successful vaccination rates were 61% and 56%, on the basis of clinical take and seroconversion, respectively. Adverse events among the vaccinees were minor. Seventy-nine (88%) of the 90 vaccinees with clinical take also seroconverted ( kappa =0.779). The level of preexisting antibodies inversely correlated with the rates of clinical take and seroconversion (P
