Vaccination-Related Side Effects, Humoral Immunity, and Adverse Events during the Civilian Smallpox Vaccination Campaign, Arkansas, 2003.

Abstract

Smallpox vaccination has been associated with notable side effects and adverse events. This study assessed the frequency of each among public health workers immunized during the 2003 Arkansas civilian smallpox vaccination campaign to allow individuals and policymakers to make informed decisions whether repeat vaccination, as recommended in 10-year intervals, should be considered. This descriptive study summarizes postvaccination surveillance data for all civilians receiving smallpox vaccine (Dryvax) in Arkansas in 2003. Rates of side effects and adverse events were determined. Vaccinia-specific antibody titers among a subset of public health response team members were also assessed. Of the 1,124 vaccine recipients, 87% had a major take response. Substantial symptomatology, a 2% adverse event rate, a 0.5% hospitalization rate, and zero inadvertent transmission following vaccination were observed. Vaccinia-specific antibody titers increased on average 9-fold from 2.21*10(2) to 2.16*10(3) onemonth after vaccination. We found no association of age, sex, or racial subgroups with adverse events, hospitalizations, a lower take response rate, or lower postvaccination antibody titers. Prominent side effect profiles and adverse events among study participants seem to support individual and institutional reluctance to vaccinate civilians in the absence of smallpox reemergence.