KEYWORDS:
safety, adverse events, thimerosal, autoimmune disease, diabetes, allergy

BACKGROUND:
The IOM's Immunization Safety Review Committee has completed its first year of work reviewing timely topics in immunization safety. The committee addresses one topic at a time, and issues three reports per year. The first four topics dealt with MMR vaccine and autism, thimerosal and neurodevelopmental disorders, multiple vaccinations and immune system dysfunction, and hepatitis B vaccine and demyelinating disease.

OBJECTIVE(S):
The committee assesses the scientific and social significance of each safety issue. The committee makes recommendations regarding research, policy, and communication. The committee was established to assist CDC and NIH prioritize its vaccine safety efforts and to provide an unbiased scientific assessment of vaccine safety concerns for scientists, parents, vaccine providers, and policy makers.

METHOD(S):
The committee holds scientific meetings, reviews published literature, commissions background papers, and reviews ongoing research. The committee focuses on evidence that a biological mechanism exists by which a vaccine could cause the adverse event and on epidemiological evidence in support for or against a causal relationship.

RESULT(S):
The committee will have released three reports and will be preparing a fourth. The committee concluded that the evidence favors rejection of a causal relationship between MMR vaccine and autistic spectrum disorder and that the biological plausibility of that putative assocation is fragmentary and inconclusive. The committee further concluded that the evidence is inadequate to accept or reject a causal relationship between thimerosal-containing vaccines and neurodevelomental disorders, although the hypothesis is biologically plausible.

CONCLUSIONS(S):
This session will include a discussion of the findings from its first year with a particular emphasis on the differences and similarities between biological plausibility and causation. Conclusions on policy review and communication will be discussed.

LEARNING OBJECTIVES:
The objective is to better understand causality assessments, including the role of biological plausibility, and how they influence vaccine policy and communication.