RESUMEN
OBJECTIVE: To quantify the population at risk of serious adverse reactions to replicating smallpox vaccine. DESIGN AND SAMPLE: Conditions known or suspected to carry risk were identified via Centers for Disease Control and Prevention planning documents, other federal publications, and peer-reviewed literature. Conditions identified were categorized as historically recognized risks or more recently recognized immunocompromised states that may pose risk. Major historical risk factors were as follows: eczema/atopic dermatitis, pregnancy, HIV, and primary immunodeficiency. More recently identified states were as follows: rheumatoid arthritis, inflammatory bowel disease, dialysis, bone marrow transplant recipients within 24 months post-transplant, solid-organ transplant recipients within 3 months post-transplant, age under 1 year, and systemic lupus erythematosus. MEASURES: The estimated prevalence or absolute number of affected individuals for each condition was ascertained from peer-reviewed studies, vital statistics, and registry databases. RESULTS: An estimated 48,121,280 to 50,028,045 individuals (15.2-15.8% of the U.S. population) are potentially contraindicated to replicating smallpox vaccine. This rises to 119,244,531 to 123,669,327 (37.4-38.8%) if household contacts are included. CONCLUSIONS: These figures are significant and larger than the only previously published study. Understanding this number allows for improved clinical utilization, equitable attention to the health needs of a vulnerable population, and strategic vaccine stockpiling.