Researchers to study mixing and matching different COVID-19 vaccines as boosters

Posted at 6:16 PM, Jun 03, 2021

As the country pushes to get more people vaccinated, researchers are now looking at mixing and matching different COVID vaccines as a booster for fully vaccinated people.

“We call it mix and match because we’re looking at people who got any of the three EUA authorized vaccines: the Pfizer, the Moderna, or the Janssen vaccine,” said Dr. Robert Atmar, one of the trial’s principal investigators. “At least in the current part of the study, we’re boosting each of those three groups with the Moderna vaccine.”

The National Institutes of Health started a clinical trial where people who’ve been fully vaccinated against COVID-19 will get booster doses of different COVID-19 vaccines to determine the safety and immune response of mixed boosted regimens.

It will include people who’ve already gotten one of the three COVID-19 vaccine regimens currently available under the FDA’s Emergency Use Authorization (EUA): the Johnson & Johnson, Moderna, and Pfizer vaccines.

Twelve to 20 weeks after their initial vaccine regimen, participants will get a single booster dose of Moderna.

“It’s really to address the question of if a person got their EUA vaccine, and they got the Pfizer vaccine, and there ends up being a recommendation for a booster vaccine, is it okay that they get boosted with some other vaccine?” said Dr. Atmar.

Dr. Atmar, who is a Professor of Infectious Diseases at Baylor College of Medicine in Houston, says the study is an adaptive design, meaning they can add more groups as they go forward. People who haven’t gotten a COVID vaccine can also participate in a separate cohort. They’ll first get the two-dose Moderna vaccine and will then be assigned to get a booster dose of a vaccine about 12 to 20 weeks later.

“When you go to get your flu shot, for example, you don’t necessarily even have a choice, and it doesn’t really matter because the vaccines are all kind of similar, right?” said USF Heath associate professor Dr. Michael Teng. “The point is that you’re immunizing people against the same thing.”

The initial trial results are expected late this summer. Dr. Teng explained why this concept will be important down the road.

“If we do in fact need a booster shot for this, you don’t want to have to go track down the same vaccine that you got because that may not be available in your area or wherever you’re getting your vaccines,” said Teng. “It’s important to be able to just find that vaccine and go and get it.”