2000a). It listed an array of studies that were unpublished or ongoing that could contribute to the body of information on which conclusions regarding health effects could be based.

As the study presented in this report began, representatives of DoD provided assurances to IOM that all relevant information from DoD would be made readily available to the committee and that efforts would be made to publish the data from completed studies. DoD and its investigators have followed through on these assurances. Most of the studies that have been carried out by DoD investigators to assess the safety and efficacy of the anthrax vaccine have now been written up as manuscripts and submitted for publication. Additional studies have been published since the letter report was released (e.g., CDC, 2000a; Gunzenhauser et al., 2001; Pittman et al., 2001, 2002; Rehme et al., 2002). In addition, one of the most important contributions to the committee’s evaluation was in the form of analyses of data from military databases carried out at the committee’s request. In accordance with its charge, the earlier IOM committee (Committee on Health Effects Associated with Exposures During the Gulf War) reviewed only the published, peer-reviewed literature to reach its conclusions about safety. The current committee had a different purpose and as a result chose to review all the studies it was aware of and for which adequate descriptions of the study methods, data analyses, and results were made available. These studies are systematically reviewed in the chapters that follow.

Several previous IOM committees evaluating possible causal associations between vaccines or other exposures and specific health outcomes have chosen to describe their findings with a weight-of-evidence approach (IOM, 1991, 1994, 2000b). Their findings placed associations between the exposure of interest and the health outcome into categories such as sufficient evidence of a causal relationship, sufficient evidence of an association, limited or suggestive evidence of an association, inadequate or insufficient evidence to determine whether an association does or does not exist, and limited or suggestive evidence of no association. The current committee chose not to use that approach because it was not asked to evaluate exposure to AVA as a cause of specific health outcomes. Rather, the committee was asked to provide an overall evaluation of the anthrax vaccine’s safety. In addition, its charge included addressing various aspects of the efficacy of AVA, as well as manufacturing issues, two topics for which a weight-of-evidence approach is not readily applicable.