Health Advice



Vaccine trial participants who received placebo now hop the line for the real thing from Pfizer, Moderna

Judy Peres, Chicago Tribune on

Published in Health & Fitness

Good news for tens of thousands of volunteers in the COVID-19 vaccine trials: Many of those who received a placebo are now being offered a vaccine — in some cases, earlier than they would otherwise have been eligible.

Participants in Pfizer’s vaccine study — some of whom had mounted a noisy campaign on social media — have been advised that anyone who wants one can receive the first of two shots by March 1. Participants in Moderna’s vaccine trial are already getting immunized.

That wasn’t always the plan, and some experts fear “unblinding” volunteers — that is, letting them know whether they got the vaccine or a placebo — could make it difficult to collect good, long-term data on the experimental vaccines, including how safe they are and when their immunity starts to wear off. But others argue it would be unfair to leave trial participants unprotected from a raging pandemic when an effective vaccine is available.

“Who brought you here?” asked Dr. Larry Corey, a virologist at Fred Hutchinson Cancer Research Center in Seattle and co-leader of the vaccine testing program for the U.S. government’s Operation Warp Speed. “Social justice says you should vaccinate all the placebo recipients as quickly as you can.”

He noted that vaccine lots manufactured and labeled for clinical trials are earmarked exclusively for research: “These vials of vaccine can’t be given to anyone else.”

When they registered for clinical trials, volunteers signed consent forms agreeing to be randomly assigned to receive shots of an experimental vaccine or a placebo — salt water — and to be followed for two years. Nothing was mentioned on those forms about placebo recipients getting the real vaccine if and when it was approved.


But the trials, nearly all supported by Operation Warp Speed, have reportedly been spectacularly successful. In a matter of months, two vaccines — those developed by Moderna and Pfizer/BioNTech — collected enough evidence of safety and efficacy to receive approval for emergency use from the federal Food and Drug Administration, and at least one more — Janssen’s — is believed to be close behind.

An unknown number of volunteers have been offered vaccine shots through their work or their local health department and have dropped out of the trials. The threat of losing study participants to follow-up may have sped up the unblinding process.

“It’s critical, no matter what they got, that we continue to observe these folks, particularly for evidence of waning immunity,” said Dr. Steven Goodman, professor of epidemiology at Stanford School of Medicine. “If too many people feel they’re disadvantaged by being in the trial, you could lose a lot of people to follow-up.”

Michael Tovar of Los Angeles, who owns a postproduction film company with his husband, Brian Levin, is a volunteer in the Pfizer trial. He doesn’t know whether he received a vaccine or placebo and was sorely disappointed when he was told he’d have to wait until his fourth clinic visit — April 6 — to find out.


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