Tens of thousands of Americans have volunteered to try COVID-19 vaccines, but only about half of them got the real one during the trials.
Now, with the first vaccine launches and an increase in coronavirus infections, experts are debating what to do about half who got a fictitious shot.
Should a vaccine be offered to everyone now? Or should the two groups from Pfizer and Moderna studies remain intact to collect long-term data on how vaccines work?
“There’s a real strain here,” said Dr. Jesse Goodman, an infectious disease specialist and former chief scientist at the U.S. Food and Drug Administration. “There is no easy answer.”
HOW VACCINE STUDIES WORK
New drugs, vaccines, or treatments often go through rigorous testing and evaluation before reaching regulators for approval.
For vaccines, researchers compare what happens when a large group of volunteers receive the vaccines, compared to what happens to another large group that does not. They compare the side effects of each group. And they measure the effectiveness of the vaccine by looking at how many in each group detect infections.
To do so fairly, researchers randomly assign participants who receive a vaccine or a vaccine, usually a dose of salt water.
Volunteers know that there are 50-50 chances that they can be included in either group, and they are not told in which group they landed. Often, researchers or other people involved in the tests are also “blinded” and don’t know it either.
SHOULD TEST VOLUNTEERS BE DISCLOSED?
Approximately 17,000 of the participants in the Moderna study received a placebo, as did some 22,000 people at the Pfizer trial.
With the coronavirus crisis underway, health experts are concerned about leaving them in the dark and unprotected. They argue that they should now be vaccinated in recognition of their willingness to be part of the trials during the pandemic.
“Volunteers have been instrumental,” said Moncef Slaoui, chief scientist of the government’s Warp Speed operational program. “They should be rewarded for it.”
Companies should “unlink” or “unmask” the studies, revealing whether participants received the vaccine or the false shot.
Unmasking is usually done at the end of the tests. Moderna and Pfizer, however, designed their studies to last two years for long-term follow-up.
“I don’t think anyone thinks it’s reasonable or feasible to keep people blind for two years,” said Susan Ellenberg, a clinical trials expert at the University of Pennsylvania.
“Given that we have a pandemic, people are willing to settle for short-term results.”
PROS AND CONS OF “UNMASKING”
With the launch of vaccines and the uncertainty of their status, volunteers could decide to drop them off once they are eligible to get one. They could stay in the study if they are told what they got, said Dr. Ana Iltis, a bioethicist at Wake Forest University.
“The participants could leave too much. They could say, ‘If you don’t tell me what I have, get out of here,’ “Iltis said.” You can’t force people to stay. “
In an ideal world, participants could hold out to find out if they received the vaccine or the vaccine. But experts agree that the current circumstances are extraordinary.
However, unmasking participants would undoubtedly affect the scope and results of the trials.
If someone knows they have already been vaccinated, for example, they may stop socially distancing themselves or wearing masks, increasing their potential exposure to the virus, and possibly spreading it. It is not yet known if vaccinated people can still carry and transmit the virus.
On the other hand, if a person discovers that they have only received the fictitious shot, they may take precautions that they would not do otherwise.
Either result, Goodman said, “means the trial is basically over.”
Before granting its emergency approval, the FDA required it Pfizer and Moderna will provide two months of tracking data. If studies are reduced, it becomes more difficult to obtain long-term effects, including the duration of immunity.
“There’s a reason we do clinical research in a certain way,” Iltis said. “We must not abandon our rules and principles. Will we be happy with short-term evidence in a year? ”
WHAT COMPANIES SAY
Pfizer plans to end vaccination of all study participants. He is opting for a voluntary and more gradual process. The company will offer this option to those who receive fake shots as soon as they have access to the vaccine outside the studio.
Modern plans to offer the vaccine immediately to all who receive fake shots. More than a quarter of them are health workers and, anyway, are the first to get the vaccine, the company noted.
“Many are gone. Unfortunately, it’s not a small number, “said Dr. Lindsey Baden, who is taking part in Moderna’s vaccine test at Boston’s Brigham and Women’s Hospital.” That’s not theoretical. It’s happening. “
The British pharmaceutical company AstraZeneca, which has so far enrolled at least 23,000 in its ongoing study in the United States, recently decided to offer individual participants the opportunity to be unmasked as they become eligible for approved vaccines.
“You never want to stop blinding,” said Dr. William Hartman, an AstraZeneca trial researcher at the University of Wisconsin-Madison.
However, he added, the pandemic has complicated things.
“A lot of people are nervous and scared,” Hartman said. “And everyone goes to trial hoping he’ll get the vaccine.”
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The Associated Press Health and Science Department is supported by the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.