Tens of thousands of Americans offered to test the COVID-19 vaccines, but only about half of them received the real vaccine during the tests.
Now, with the first vaccine launches and an increase in coronavirus infections, experts are debating what to do with the half that received a dummy injection.
Now, should everyone get a vaccine? Or should the two groups in the Pfizer and Moderna studies remain intact to collect long-term data on how vaccines work?
“There is real tension here,” said Dr. Jesse Goodman, an infectious disease specialist and former chief scientist with the U.S. Food and Drug Administration. “There is no easy answer.”
HOW VACCINE STUDIES WORK
New drugs, vaccines or treatments often undergo rigorous testing and evaluation before reaching regulators for approval.
For vaccines, the researchers compare what happens when a large group of volunteers takes the vaccines and what happens with another large group that does not. They compare side effects in each group. And they measure the effectiveness of the vaccine by looking at how many in each group get infections.
To do this fairly, the researchers randomly assign participants to receive a vaccine or a dummy injection, usually a dose of salt water.
Volunteers know that there is a 50-50 chance of being placed in any of the groups – and they are not told which group they belong to. Often, researchers or other people involved in the tests are also “blind” and don’t know it either.
SHOULD TEST VOLUNTEERS BE GIVEN?
About 17,000 of the participants in the Moderna study received a placebo, as did about 22,000 people in the Pfizer study.
With the ongoing coronavirus crisis, health experts are concerned about leaving them in the dark and unprotected. They argue that they should get a vaccine now, in recognition of their willingness to be part of the tests during the pandemic.
“The volunteers were instrumental,” said Moncef Slaoui, chief scientist for the government’s Operation Warp Speed program. “They should be rewarded for that.”
The companies would have to “unveil” or “unmask” the studies, revealing whether the participants received the vaccine or the false injection.
Unmasking is usually done at the end of the test. Moderna and Pfizer, however, designed their studies to last two years to do a long-term follow-up.
“I don’t think there is anyone who thinks it is reasonable or feasible to keep people blind for two years,” said Susan Ellenberg, a specialist in clinical trials at the University of Pennsylvania.
“Since we have a pandemic, people are ready to settle for short-term results.”
PROS AND CONS OF “UNMASKING”
With the launch of vaccines and the uncertainty of their status, volunteers can decide to give up as soon as they are eligible to obtain it. They can stay in the study if they know what they have, said Dr. Ana Iltis, a bioethicist at Wake Forest University.
“Participants could leave in droves. They could say, ‘If you don’t tell me what I have, I’m out of here,’ ”said Iltis. “You can’t force people to stay.”
In an ideal world, participants could wait to find out whether they received the dummy injection or the vaccine. But experts agree that the current circumstances are extraordinary.
Still, unmasking participants would undoubtedly affect the scope and results of the trials.
If someone finds out that they have already been vaccinated, for example, they can stop distancing themselves socially or wear masks – increasing their potential exposure to the virus and possibly spreading it. It is not yet known whether vaccinated people can still carry and transmit the virus.
On the other hand, if a person finds out that he has only received the false shot, he can take precautions that he would not have taken otherwise.
Either outcome, Goodman said, “means that the trial has basically come to an end.”
Before granting its emergency use approval, the FDA required Pfizer and Moderna to provide two-month follow-up data. If studies are interrupted, long-term effects, including the duration of immunity, become more difficult to obtain.
“There is a reason for doing clinical research in a certain way,” said Iltis. “We must not abandon our norms and principles. Will we be happy with short-term evidence in a year? “
WHAT COMPANIES SAY
Pfizer plans to vaccinate all study participants. It means choosing a more gradual and voluntary process. The company will offer this option to those who take simulated injections as soon as they have access to the vaccine outside the study.
Moderna is considering offering the vaccine immediately to everyone who has received fake injections. More than a quarter of them are health workers and the first in line for the vaccine anyway, the company noted.
“Many have already left. Unfortunately, it’s not a small number, ”said Lindsey Baden, who is involved in testing Moderna’s vaccine at Brigham and Women’s Hospital in Boston. “This is not theoretical. Is happening.”
British pharmaceutical company AstraZeneca, which has enrolled at least 23,000 so far in its ongoing US study, recently decided to offer individual participants the opportunity to be unmasked as they become eligible for approved vaccines.
“You never really want to unravel it,” said Dr. William Hartman, a researcher in the AstraZeneca study at the University of Wisconsin-Madison.
However, he added, the pandemic has complicated things.
“A lot of people are nervous and scared,” said Hartman. “And everyone enters the test hoping to receive the vaccine.”
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The Associated Press Department of Health and Science receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.