Study designs for evaluating different efficacy and effectiveness aspects of vaccines

Am J Epidemiol. 1997 Nov 15;146(10):789-803. doi: 10.1093/oxfordjournals.aje.a009196.


Vaccine efficacy and effectiveness (VE) are generally measured as 1 minus some measure of relative risk (RR) in the vaccinated group compared with the unvaccinated group (VE = 1 - RR). In designing a study to evaluate vaccination, the type of effect and the question of interest determine the appropriate choice of comparison population and parameter. Possible questions of interest include that of the biologic effect of vaccination on susceptibility, on infectiousness, or on progression to disease in individuals. The indirect effects, total effects, and overall public health benefits of widespread vaccination of individuals within the context of a vaccination program might also be of primary concern. The change in behavior induced by belief in the protective effects of vaccination might influence the estimates of these effects or might itself be of interest. In this paper, the authors present a framework of study designs that relates the scientific question of interest to the choice of comparison groups, the unit of observation, the level of information available for analysis, and the parameter of effect.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Algorithms
  • Clinical Trials as Topic
  • Communicable Disease Control / statistics & numerical data
  • Disease Progression
  • Disease Susceptibility / epidemiology
  • Disease Transmission, Infectious / prevention & control
  • Disease Transmission, Infectious / statistics & numerical data
  • Epidemiologic Research Design*
  • Health Behavior
  • Humans
  • Incidence
  • Probability
  • Proportional Hazards Models
  • Risk
  • Terminology as Topic
  • Vaccination / standards*
  • Vaccines / administration & dosage
  • Vaccines / standards*


  • Vaccines