Policy ForumEthics: COVID-19

COVID-19 vaccine trial ethics once we have efficacious vaccines

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Science  11 Dec 2020:
Vol. 370, Issue 6522, pp. 1277-1279
DOI: 10.1126/science.abf5084


The unprecedented effort to identify one or more safe and effective vaccines for COVID-19 includes more than 180 candidates in development (1), with at least 12 in phase 3 trials (2). The testing of so many vaccine candidates, in a pandemic of a disease for which there are to date limited treatment options, raises a critical challenge: What should researchers do if a vaccine candidate is judged to be safe and efficacious? Guidance from the U.S. Food and Drug Administration (FDA) states that in the event that a COVID-19 vaccine candidate is judged to be “safe and effective,” discussion may be necessary “to address ethical arguments to break the blind and offer vaccine to placebo recipients” (3). We consider here two questions raised by this guidance: First, if a vaccine candidate is found to be safe and efficacious in a placebo-controlled trial, should the researchers continue that trial as designed? Second, should researchers continue to test other vaccine candidates using placebo-controlled trials? These two questions are especially timely given recent announcements by Pfizer and Moderna that their vaccine candidates have been found to be efficacious in preventing symptomatic COVID-19 (4, 5).

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