The US smallpox vaccination program: a review of a large modern era smallpox vaccination implementation program.

We describe the US experience with a large-scale smallpox vaccination program in the modern era and quantify the anticipated and unanticipated local and systemic side-effects of smallpox vaccination. In addition, we review unexpected issues, such as the development of myopericarditis discovered during the implementation of this program. These results constitute the largest dataset of a vaccinia vaccination program utilizing calf-lymph derived New York City Board of Health strain vaccine (Dryvax, Wyeth) since the 1970s. These results should inform current and future vaccinia vaccination programs and provide a historical rate of complications against which candidate vaccine side-effects can be compared in future clinical trials.