OBSERVATION Adverse Events Following Smallpox Vaccination With ACAM2000 in a Military Population

thems are 2 adverse events that have been associatedwith the smallpox vaccination. Accurate incidence and preva-lence rates of each are not readily available, but these events are thought to be uncommon. To our knowl-edge, this is the first case series to provide clinical as well as pathologic descriptions of multiple papulovesicular eruptions occurring after receiving the second-generation smallpox vaccine, ACAM2000 (Acambis, Can-ton, Massachusetts), among a vaccinia-naïve military population. In addition,we report the first confirmed case, to our knowledge, of generalized vaccinia following ad-ministration of the ACAM2000 vaccine. Observations: All patients received primary smallpox immunization as well as 1 to 3 concurrent or near-concurrent (within the preceding 21 days) immuniza-tions for typhoid, anthrax, hepatitis B, and/or seasonal influenza. One patient presented with a flulike pro-drome and diffuse vesiclopustules covering the face, neck, chest, back, and upper and lower extremities. Vaccinia polymerase chain reaction confirmed generalized vac-cinia. The remaining 7 patients presented with unusual, painful, and pruritic papulovesicular eruptions occur-ring on the extensor surfaces of their upper and lower extremities without systemic symptoms. Histologic find-ings revealed 2 general patterns, including a dermal hy-persensitivity reaction with lymphocytic vasculitis and a vesicular spongiotic dermatitis with eosinophils. Conclusions:Wepresent the first confirmed case of gen-eralized vaccinia following immunizationwith the second-generation smallpox vaccine ACAM2000. In addition, we describe 7 cases of benign, acral, papulovesicular erup-tions thought to be associated with ACAM2000 admin-istration. Further research is needed to discern the patho-genesis of these benign eruptions aswell as their incidence and prevalence and that of generalized vaccinia wit