(e.g., redness and swelling at the injection site, subcutaneous nodules) occurred more frequently with subcutaneous than with intramuscular injections (5–7 percent). Male vaccine recipients reported local reactions less frequently after subcutaneous injections (5–32 percent) than female vaccine recipients (39–66 percent). The report did not describe the type of monitoring for adverse health effects.

Tripler Army Medical Center Survey. A self-administered questionnaire was used to collect data on 603 health care personnel who received the anthrax vaccine at Tripler Army Medical Center beginning in September 1998 (CDC, 2000). As reported in congressional testimony, the survey found a high incidence of local transient reactions (70 percent with subcutaneous nodules and 65 percent with muscle soreness) (Claypool, 1999). Muscle aches, the most frequently reported systemic complaint, were reported in 15 percent of vaccine recipients. Three VAERS reports were submitted on the individuals in this study, and one individual lost more than a day of work; there were no hospitalizations. Gender differences in the number of reactions have been noted in this study. A higher proportion of women reported outpatient visits (e.g., after the second dose, 2.0 percent of males and 13.8 percent of females reported making outpatient visits) and local reactions (e.g., after the second dose, 20.4 percent of males and 46.9 percent of females reported moderate to severe redness) (GAO, 1999d).

Additional studies. The U.S. Air Force is completing a study comparing visual acuity in 354 vaccinated aircrew members with 363 aircrew personnel who were not vaccinated against anthrax. Preliminary analysis reported in congressional testimony indicates that changes in visual acuity occurred in 12 percent of vaccinated and 16 percent of unvaccinated crew members during the course of a year (Claypool, 1999).

Service members stationed in Korea completed a mandatory questionnaire when they reported for anthrax vaccination. Questions included the service member’s reaction to the previous dose of the anthrax vaccine. Data from 6,879 questionnaires noted gender differences in the reported rate of transient adverse reactions, with higher rates in women. After the first or second dose of the vaccine, 82 (1.9 percent) of 4,348 men and women reported limited effects on their work performance, 21 (0.5 percent) went to the clinic for evaluation, and 1 required hospitalization for an injection site reaction (CDC, 2000).

Conclusions on Human Studies

There is a paucity of published peer-reviewed literature on the safety of the anthrax vaccine. The committee located only one randomized peer-reviewed study of the type of anthrax vaccine used in the United States (Brachman et al., 1962). However, the formulation of the vaccine used in that study differs somewhat from the vaccine given to Gulf War veterans (and currently in use). The Brachman study (and other early experimental studies) found transient local and systemic effects (primarily erythema, edema, induration) of the anthrax vaccine.

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