TABLE 7.

Hill's criteria for causation in diseasea

CriterionAssociation
Strength of associationWhat is the relative increased risk in disease after exposure to virus?
Consistency of associationHow reproducible are the data with different methods and by different laboratories, etc.?
Specificity of associationIs the disease unique to exposure to virus?
TemporalityDoes disease follow exposure?
Biological gradientDoes an increased dose of virus lead to more rapid onset or more severe symptoms?
PlausibilityIs a causal relationship biologically plausible?
CoherenceIs a relationship compatible with present knowledge of the disease?
ExperimentDoes experimental manipulation or intervention affect disease outcome, e.g., therapy?
AnalogyIs there a comparable association with related virus or disease, e.g., animal models?
  • a Adapted from reference 152 with permission. See also reference 210.