The committee concludes that there is inadequate/insufficient evidence to determine whether an association does or does not exist between multiple vaccinations and long-term adverse health effects.


The committee reviewed the available scientific evidence in the peer-reviewed literature in order to draw conclusions about associations between the agents of interest and adverse health effects in all populations (see Table 1). The committee placed its conclusions in categories that reflect the strength of the evidence for an association between exposure to the agent and health outcomes. The committee could not measure the likelihood that Gulf War veterans’ health problems are associated with or caused by these agents. To address this issue, the committee would need to compare the rates of health effects in Gulf War veterans exposed to the putative agents with the rates of those who were not exposed, which would require information about the agents to which individual veterans were exposed and their doses. However, as discussed throughout this report, there is a paucity of data regarding the actual agents and doses to which individual Gulf War veterans were exposed. Further, to answer questions about increased risk of illnesses in Gulf War veterans, it would also be important to know the degree to which any other differences between exposed and unexposed veterans could influence the rates of health outcomes. This information is also lacking for the Gulf War veteran population. Indeed most of the evidence that the committee used to form its conclusions about the association of the putative agents and health effects comes from studies of populations exposed to these agents in occupational and clinical settings, rather than from studies of Gulf War veterans. Due to the lack of exposure data on veterans, the committee could not extrapolate from the level of exposure in the studies that it reviewed to the level of exposure in Gulf War veterans. Thus, the committee could not determine the

TABLE 1 Summary of Findings

Sufficient Evidence of a Causal Relationship

Evidence is sufficient to conclude that a causal relationship exists between the exposure to a specific agent and a health outcome in humans. The evidence fulfills the criteria for sufficient evidence of an association (below) and satisfies several of the criteria used to assess causality: strength of association, dose–response relationship, consistency of association, temporal relationship, specificity of association, and biological plausibility.


  • Exposure to sarin and a dose-dependent acute cholinergic syndrome that is evident seconds to hours subsequent to sarin exposure and resolves in days to months.

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