Last fall, Ivan Rusyn, a professor in the Texas A&M College of Veterinary Medicine and Biomedical Sciences’ (CVM) Department of Veterinary Integrative Biosciences (VIBS), was asked by the National Academies of Sciences, Engineering, and Medicine to chair an ad hoc committee to review a report on how the military approaches the medical cases of veterans who were exposed to a variety of chemical and biological test substances between 1942 and 1975.
These experiments were conducted by the United States Department of Defense (DoD) to test on volunteer human subjects chemical and biological agents, simulants, tracers, vaccines, and medications.
To evaluate whether these exposures may have caused long-term health consequences to the test subjects, in 2016, the Army commissioned a report—”Assessment of Potential Long-Term Health Effects on Army Human Test Subjects of Relevant Biological and Chemical Agents, Drugs, Medications and Substances: Literature Review and Analysis”—that identified 18 compounds as having evidence of potential long-term adverse health effects.
Rusyn and the eight other committee members were charged with evaluating this report to determine whether it appropriately identified and characterized potential long-term health effects. They were also asked to evaluate the Army’s approach to evaluate agent- and outcome-specific associations.
In April, Rusyn briefed the DOD on the committee’s findings and recommendations, reporting that the Army’s 2016 report is suitable for scoping and setting priorities for further assessment; however, the committee also noted that the report should not be used as the sole basis to assess potential long-term health effects.
“The challenge that the DOD is facing is enormous as they consider applications for medical care to health conditions that may have resulted from exposures decades ago,” Rusyn said. “The number of potential harmful agents and the need to evaluate the causality of the associations between exposure and effect are daunting given the short timelines and a limited staffing the agency has. Thus, the major accomplishment of the committee was to develop a streamlined, scientifically rigorous approach to categorize health hazards, an approach that will be useful to other local, state and federal agencies that are tasked of protecting human health.”
For the future, the committee recommended that the Army’s approach be based on a six-step strategy that includes:
- Prioritizing the list of relevant factors on the basis of applications from veterans, the number of subjects likely exposed to each test agent, the report findings, and established hazard classifications;
- Defining the scope for evidence evaluation by formulating a question and determining whether hazard or risk assessments are available from authoritative sources;
- Developing a review protocol for searching and screening literature and provide guidelines for determining study quality;
- Evaluating each individual study quality, synthesizing each line of evidence by considering such factors as the consistency across study designs, species, and populations; dose response; and magnitude of the effect;
- Specifying the weight-of-evidence approach that will be used to make determinations about associations and document how the weigh-of-evidence conclusions were drawn; and
- Drawing hazard identification conclusions, including a concluding statement that specifies the test agent, exposure scenario(s), health effect(s), and strength of association.