Gastrointestinal adverse reactions following anthrax vaccination: an analysis of the Vaccine Adverse Events Reporting System (VAERS) database

Abstract

Background/aims: The Institute of Medicine (IOM) of the United States Academy of Sciences in 2000 encouraged the evaluation of active long-term monitoring studies of large populations to further evaluate the relative safety of anthrax vaccine. Anthrax is a deadly bacterial infectious disease that currently has been engineered as a biological warfare agent. The vaccine produced against anthrax is a cell-free crude culture of the various toxin components of the natural disease. The U.S. military current goal is to vaccinate its entire personnel by 2003. The purpose of this study was to evaluate anthrax vaccination and its association with arthritic, immunological and gastrointestinal adverse reactions based upon analysis of the Vaccine Adverse Events Reporting System (VAERS) database.

Methodology: We analyzed the VAERS database from 15 December 1997 to 12 April 2000. We also compared the incidence of anthrax adverse reactions with the incidence of adverse reactions reported to VAERS after adult tetanus vaccination.

Results: Anthrax vaccine was one of the most reactogenic vaccines included in VAERS. The incidence of adverse reactions reported following anthrax vaccine was higher for every reaction analyzed in comparison to the adult vaccine control groups.

Conclusions: The current anthrax vaccine may be acceptable in military populations in impending threat of anthrax exposure, the cost-benefits of vaccination in less high risk military populations may be more questionable. Civilian anthrax vaccination will require a less reactogenic vaccine. Civilian doctors should be aware of anthrax vaccine adverse reactions. Military and civilian doctors should also be diligent in their reporting to VAERS of cases of adverse reactions to anthrax vaccine.