COVID-19 Vaccines: Placebo Crossover May Depend Upon Number Of Doses, Allocation Strategy

20 Nov 2020

Although US FDA wants sponsors to maintain blinded Phase III follow-up as long as possible after emergency use authorization or licensure, vaccine researcher Larry Corey says it will become ‘untenable’ to keep individuals in placebo arm once they qualify for vaccine access under the allocation framework.

Editorial use only - ARCADIA, CA - MAR 20: Horses break from the gate in an allowance race at Santa Anita Park on Mar 20, 2010 in Arcadia, CA — Once the first COVID-19 vaccines out of the gate become available, clinical trials of earlier-stage candidates might look different. • Source: Shutterstock

The timing of when individual placebo patients in randomized Phase III trials of COVID-19 vaccines should be allowed access to those vaccines once authorized or licensed by the US Food and Drug Administration may depend upon the number of doses available and the populations prioritized for initial distribution.

Larry Corey, a virologist at Fred Hutchinson Cancer Research Center and co-leader of the COVID-19 Prevention Network’s vaccine testing program,...