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In an ideal world, vaccine trial participants might wait to find out whether they received the sham injection or the vaccine. But experts agree that current circumstances are extraordinary
Tens of thousands of people in the United States and around the world have volunteered to take the test. COVID-19
vaccines, but only about half of them received the actual vaccine during the trials.
Now, with the first vaccine launches and an increase in coronavirus infections, experts in the US are debating what to do with the half who received a fake injection.
Should a vaccine be offered to everyone now? Or should the two groups of the Pfizer and Moderna studies remain intact to collect long-term data on how well vaccines work?
“There is a real tension here,” said Dr. Jesse Goodman, infectious disease specialist and former chief scientist for the US Food and Drug Administration. “There is no easy answer.”
How Vaccine Studies Work
New drugs, vaccines, or treatments generally go through rigorous testing and evaluation before reaching regulators for approval.
In the case of vaccines, the researchers compare what happens when a large group of volunteers receive the injections with what happens to another large group that does not. They compare the 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 to 50 chance that they will be included in either group, and they are not told which group they came into. Often times, the researchers or other people involved in the tests are also “blind” and do not know.
Should volunteers be informed of the test?
About 17,000 of the Moderna study participants received a placebo, as did about 22,000 people in the Pfizer trial.
With the continuous coronavirus crisis, health experts worry about leaving them in the dark and unprotected. They argue that they should receive a vaccine now in recognition of their willingness to be part of the trials during the pandemic.
“Volunteers have been critical,” said Moncef Slaoui, chief scientist for the government’s Operation Warp Speed program. “They should be rewarded for it.”
The companies would have to “unmask” or “unmask” the studies, revealing whether the participants received the vaccine or the sham injection.
Unmasking is usually done at the end of the test. Moderna and Pfizer, however, designed their studies to last two years for long-term follow-up.
“I don’t think there is anyone who 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.
“Since we have a pandemic, people are ready to settle for short-term results.”
Pros and cons of unmasking
With vaccines launching and their status uncertain, volunteers could decide to drop out once they are eligible to receive one. They could stay in the study if they tell them what they got, said Dr. Ana Iltis, a bioethicist at Wake Forest University.
“Participants could leave en masse. They might say, ‘If you don’t tell me what I have, I’m getting out of here,’ ”Iltis said. “You can’t force people to stay.”
In an ideal world, participants could wait to find out whether they received the sham injection or the vaccine. But experts agree that the current circumstances are extraordinary.
Still, unmasking participants would certainly affect the scope and results of the trials.
If someone finds out that 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 whether vaccinated people can still carry and transmit the virus.
On the other hand, if a person discovers that they only received the fake injection, they could take precautions that they would not otherwise take.
Either outcome, Goodman said, “means the trial has basically come to an end.”
Before granting its emergency use approval, the FDA required Pfizer and Moderna to provide two months of follow-up data. If studies are shortened, it becomes more difficult to obtain long-term effects, including how long immunity lasts.
“There is a reason we do clinical research in a certain way,” Iltis said. “We must not abandon our norms and principles. Are we going to be happy with the short-term evidence in a year? “
What companies say
Pfizer plans to eventually vaccinate all study participants. You are opting for a more gradual voluntary process. The company will offer that option to those who received fake injections as soon as they had access to the vaccine outside of the study.
Moderna is considering offering the vaccine right away to everyone who received bogus injections. More than a quarter of them are healthcare workers and are still first in line to receive the vaccine, the company noted.
“Many have already left. Unfortunately, it is not a small number, ”said Dr. Lindsey Baden, who is participating in the Moderna vaccine trial at Brigham and Women’s Hospital in Boston. “This is not theoretical. It’s 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 unmask themselves as they become eligible for approved vaccines.
“You never really want to stop blinding,” said Dr. William Hartman, an investigator for the AstraZeneca trial 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 comes to the trial hoping to get the vaccine.”
