Elsevier

Vaccine

Volume 32, Issue 37, 20 August 2014, Pages 4708-4712
Vaccine

WHO report
Placebo use in vaccine trials: Recommendations of a WHO expert panel

https://doi.org/10.1016/j.vaccine.2014.04.022Get rights and content
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open access

Highlights

  • Placebo controls may be acceptable even when an efficacious vaccine exists, in the following four possible situations:

  • When developing a locally affordable vaccine.

  • When evaluating the local safety and efficacy of an existing vaccine.

  • When testing a new vaccine when an existing vaccine is not considered appropriate locally.

  • When determining the local burden of disease.

Abstract

Vaccines are among the most cost-effective interventions against infectious diseases. Many candidate vaccines targeting neglected diseases in low- and middle-income countries are now progressing to large-scale clinical testing. However, controversy surrounds the appropriate design of vaccine trials and, in particular, the use of unvaccinated controls (with or without placebo) when an efficacious vaccine already exists. This paper specifies four situations in which placebo use may be acceptable, provided that the study question cannot be answered in an active-controlled trial design; the risks of delaying or foregoing an efficacious vaccine are mitigated; the risks of using a placebo control are justified by the social and public health value of the research; and the research is responsive to local health needs. The four situations are: (1) developing a locally affordable vaccine, (2) evaluating the local safety and efficacy of an existing vaccine, (3) testing a new vaccine when an existing vaccine is considered inappropriate for local use (e.g. based on epidemiologic or demographic factors), and (4) determining the local burden of disease.

Keywords

Vaccine trials
Trial design
Ethics
Placebo controls
Risk
International research

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