The Institute of Medicines Immunization Safety Review Committee: Vaccines and Autism

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The Institute of Medicines Immunization Safety
Review Committee Vaccines and Autism

• Kathleen Stratton, PhD
• Senior Program Officer
• Auburn, Alabama November 2004

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Charter

• The National Academy of Sciences was born in the
  travail of the Civil War. The Act of
  Incorporation, signed by President Lincoln on
  March 3, 1863, established service to the nation
  as its dominant purpose.

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The Institute of Medicine

• The Institute of Medicine serves as adviser to
  the nation to improve health. As an independent,
  scientific adviser, the Institute of Medicine
  strives to provide advice that is unbiased, based
  on evidence, and grounded in science. The mission
  of the Institute of Medicine embraces the health
  of people everywhere.

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Important Policies and Procedures

• Non-profit Non-governmental
• Reports by unbiased and unconflicted committees
  of volunteers
• Distance from sponsors
• Section 15 of Federal Advisory Committee Act
• Peer review
• Release and dissemination of the reports to the
  public

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Charge to the Immunization Safety Review Committee

• Scientific Assessment
• Causal relationship
• Biological mechanisms
• Significance Assessment
• Public Health Response
• Policy Review and Analysis
• Research and Surveillance
• Communications

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Categories of CausalRelationships

• Evidence establishes a causal relationship
• Evidence favors acceptance of a causal
  relationship
• Evidence favors rejection of a causal
  relationship
• Evidence is inadequate to accept or reject a
  causal relationship
• No evidence bearing on the relationship

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Vaccines and Autism Causality Assessment

• The evidence favors rejection of a causal
  relation between both MMR and thimerosal (in
  vaccines) and autism.

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Thimerosal in Vaccines and Autism Causality
Assessment

• 5 epidemiological studies were judged by the
  committee as relevant and of sufficient quality
  to support a conclusion.
• This differs from the assessment in the 2001
  report by the committee with respect to the
  evidence base and the outcome under study.

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Vaccines and Autism Biological Mechanisms

• Several hypotheses were reviewed
• Animal, in vitro, and clinical studies were
  reviewed
• Role of genetic susceptibility was considered

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Vaccines and Autism Biological Mechanisms

• The committee does not dispute that mercury,
  including thimerosal, can be damaging to the
  human body, including the brain. Thimerosal
  clearly is neurotoxic at high doses and affects
  physiological or biochemical systems at lower
  doses.

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Vaccines and Autism Biological Mechanisms

• The studies reviewed are provocative the autism
  research community should consider the
  appropriate composition of their research
  portfolio with some of these findings in mind.
  However, these experiments do not provide
  evidence of a relationship between thimerosal and
  autism

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Thimerosal and Autism Genes and Environment

• If the theory that subpopulation (genetic?)
  susceptibility to mercury-induced autism explains
  the absence of effects in epidemiological studies
  is true, then it is unlikely that thimerosal in
  vaccines has caused an epidemic of autism. The
  theory currently lacks supporting evidence

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Vaccines and Autism Biological Mechanisms

• In the absence of experimental or human evidence
  that vaccination affects metabolic,
  developmental, immune, or other physiological or
  molecular mechanisms that are causally related to
  the development of autism, the committee
  concludes that the hypotheses generated to date
  are theoretical only.

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Vaccines and Autism Significance Assessment

• The amount of thimerosal in childhood vaccines
  has been DRASTICALLY reduced it exists in trace
  amounts in some mandatory vaccines and as a
  preservative in SOME pediatric formulations of
  influenza vaccine.

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Vaccines and Autism Significance Assessment

• The committee concludes that because autism can
  be such a devastating disease, any speculation
  that links vaccines and autism means that this is
  a significant issue.

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Vaccines and Autism Public Health Response

• The committee recommends a public health response
  that fully supports an array of vaccine safety
  activities.
• The committee recommends that available for
  funding for autism research be channeled to the
  most promising areas.

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• From a public health perspective, the committee
  does not consider a significant investment in
  studies of the theoretical vaccine-autism
  connection to be useful at this time.

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• Because chelation therapy has potentially serious
  risks, the committee recommends that it be used
  only in carefully-controlled research settings
  with appropriate oversight by Institutional
  Review Boards protecting the interests of the
  children who participate.

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Contact Information

• www.iom.edu/imsafety
• imsafety_at_nas.edu