title: The swine flu vaccine and Guillain-Barré syndrome. A case study in relative risk and specific causation.
abstract: Epidemiologic methods were developed to prove general causation: identifying exposures that increase the risk of particular diseases. Courts often are more interested in specific causation: On balance of probabilities, was the plaintiff's disease caused by exposure to the agent in question? Some authorities have suggested that a relative risk greater than 2.0 meets the standard of proof for specific causation. Such a definite criterion is appealing, but there are difficulties. Bias and confounding are familiar problems; individual differences must be considered too. The issues are explored in the context of the swine flu vaccine and Guillain-Barré syndrome.
  
  
  CONCLUSIONS
  There is a considerable gap between relative risks and proof of specific causation.
authors.affiliation: University of California, Berkeley, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Freedman
authors.forename: P B
authors.initials: PB
authors.lastname: Stark
mesh_terms: D015984:Causality; D020275:Guillain-Barre Syndrome / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D017589:Immunization Programs / Q000331:legislation & jurisprudence*; D009980:Influenza A virus; D007252:Influenza Vaccines / Q000009:adverse effects*; D016365:Liability, Legal; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012306:Risk; D014481:United States / Q000453:epidemiology
chemical_list: D007252:Influenza Vaccines