Summary of GAO's Findings on the Safety and Efficacy of the Anthrax Vaccine

Pursuant to a congressional request, GAO reviewed the Department of Defense's (DOD) anthrax immunization program, focusing on the: (1) need for a six-shot regimen and annual booster shots; (2) long- and short-term safety of the vaccine; (3) efficacy of the vaccine; and (4) extent to which problems the Food and Drug Administration (FDA) found in the vaccine production facility in Michigan could compromise the safety, efficacy, and quality of the vaccine.

GAO noted that: (1) no studies have been done to determine the optimum number of doses for the anthrax vaccine; (2) a three-dose regimen was used initially for the original vaccine; (3) the number of doses was increased to six after three people who received three doses of the vaccine became infected; (4) although annual boosters are required, the need for annual booster shots has not been evaluated; (5) the long-term safety of the vaccine has not been studied; (6) DOD is designing studies to examine the vaccine's long-term effects; (7) with regard to short-term safety, according to FDA officials, data from two studies conducted prior to licensing of the anthrax vaccine are difficult to interpret since one study used the original vaccine, and part of the study population in the other study had already received the original vaccine; (8) DOD recently conducted two studies showing a higher proportion of women reported both local and systemic reactions to the vaccine than their male counterparts; (9) data from one of the studies showed more than twice the proportion of women reported they missed one or more duty shifts after their vaccinations than did males; (10) a study on the efficacy of the original vaccine concluded that it provided protection to humans against anthrax penetrating the skin but did not provide sufficient data to determine its effectiveness against anthrax that was inhaled; (11) in the late 1980s, DOD studied the efficacy of the vaccine on animals; (12) these studies support the view that the licensed vaccine can protect against exposure to some but not all strains of anthrax either by inoculation or inhalation; (13) DOD officials recognize that correlating the results of animal studies to humans is necessary and stated that they are planning research in this area; (14) FDA's inspections of the vaccine facility production in 1996 and 1998 identified deficiencies in two broad categories: (a) those affecting a limited number of batches; and (b) those that could compromise the safety and efficacy of any or all batches; (15) in 1998, the manufactor shut down the facility for renovation; and (16) a new, company, which purchased the facility in mid-1998, is addressing the issues identified by FDA.