Safety of anthrax vaccine: A review by the Anthrax Vaccine Expert Committee (AVEC) of adverse events reported to the Vaccine Adverse Event Reporting System (VAERS)

Purpose. To assess the safety of a licensed anthrax vaccine given to nearly 400 000 US military personnel, reports of adverse events (AEs) submitted to the Vaccine Adverse Event Reporting System (VAERS) were reviewed and evaluated medically. Methods. The Anthrax Vaccine Expert Committee (AVEC), a civilian panel of private-sector physicians and other scientists, reviewed 602 VAERS reports using a Delphic approach (structured expert consensus) to assess the causal relationship between vaccination and the reported AEs and sought to identify unexpected patterns in the occurrence of medically important events. Reports were entered into a database and used to profile AEs with respect to person, type/location, relative frequency, severity/impact, concomitant illness or receipt of other drugs or vaccines, and vaccine lot. Results. Nearly half the reports noted a local injection-site AE, with more than one-third of these involving a moderate to large degree of inflammation. Six events qualified as serious AEs (SAEs), and all were judged to be certain consequences of vaccination. Three-quarters of the reports cited a systemic AE (most common: flu-like symptoms, malaise, rash, arthralgia, headache), but only six individual medically important events were judged possibly or probably due to vaccine (aggravation of spondyloarthropathy (2), anaphylactoid reaction, arthritis (2), bronchiolitis obliterans organizing pneumonia). Conclusions. Since some cases of local inflammation involved distal paresthesia, AVEC recommends giving subcutaneous injections of AVA over the inferior deltoid instead of the triceps to avoid compression injury to the ulnar nerve. At this time, ongoing evaluation of VAERS reports does not suggest a high frequency or unusual pattern of serious or other medically important AEs.