Disability among U.S. Army personnel vaccinated against anthrax

This study was conducted to examine whether U.S. Army personnel receiving > or =1 dose of anthrax vaccine adsorbed (AVA) between March 1998 and February 2002 were at higher risk of disability than unvaccinated personnel. We studied a historical cohort study of 716,833 active-duty soldiers (154,456 vaccinated) followed for 4.25 years to determine rates of evaluation for disability discharge. Cox proportional hazards models compared estimated risk of evaluation for disability, accounting for occupation and sociodemographics. Adjusted hazard ratio (HR) and 95% confidence interval (CI) was 0.96 (CI = 0.92-0.99). Separate adjusted HRs for men, women, permanent and temporary disability, musculoskeletal and neurologic conditions were similar, ranging from 0.90 to 1.04. Latency assumptions did not affect results. Anthrax vaccination does not increase risk of disability. This finding may be partially the result of factors influencing selection for vaccination or vaccine tolerance.