Scientists debate real shots for vaccine volunteers

Tens of thousands of Americans have volunteered to test COVID-19 vaccines, but only about half of them got the real thing during trials.

Now, with the first vaccine rollouts and a surge in coronavirus infections, experts are debating what to do about the half that got a dummy shot.

Should everyone now be offered a vaccine? Or should the two groups in the Pfizer and Moderna studies remain intact to collect long-term data on how well the vaccines work?

“There’s a real tension here,” said Dr. Jesse Goodman, an infectious disease specialist and former chief scientist at the U.S. Food and Drug Administration. “There’s not an easy answer.”

Volunteers know there’s a 50-50 chance they could be put in either group — and they are not told which group they landed in. Often, the researchers or others involved in the testing are also “blinded” and don’t know either.

About 17,000 of Moderna’s study participants received a placebo, as did about 22,000 people in Pfizer’s trial.

With the ongoing coronavirus crisis, health experts worry about leaving them in the dark and unprotected.

“Volunteers have been instrumental,” said Moncef Slaoui, chief scientist of the government’s Operation Warp Speed program. “They should be rewarded for it.”

With the rollout of vaccines and the uncertainty of their status, volunteers could decide to drop out once they are eligible to get one. They might stay in the study if they’re told what they got, said Dr. Ana Iltis, a bioethicist at Wake Forest University.

Still, unmasking participants would undoubtedly affect the trials’ scope and results.

If people learn they’ve already been vaccinated, they may stop social distancing or wearing masks — increasing their potential exposure to the virus and possibly spreading it.

On the flip side, if study participants find out they only received the dummy shot, they might take precautions they wouldn’t otherwise.

Either outcome, Goodman said, “means the trial has basically come to an end.”