Factors Suggesting Adverse Effects of a Vaccine

Is the exact chronology of the vaccination and the adverse event known?

Is the adverse event generally accepted as a complication of the vaccine?

Is the adverse event a specific clinical syndrome which could plausibly be caused by vaccination?

Is there laboratory evidence that associates the strain of organism used in the vaccine with the adverse event?

Does readministration of the vaccine result in the same adverse event?

Do controlled clinical trials or epidemio-logic studies show a greater risk for the adverse event among vaccinated vs an unvaccinated control group?

Are the studies well-designed and free from bias?