Knowledge from NIH mix-and-match Covid vaccine booster trials prepared quickly


Dr. Anthony Fauci, director of the National Institute for Allergies and Infectious Diseases, makes an opening statement during a Senate Committee on Health, Education, Labor and Pensions hearing to discuss the ongoing federal response to COVID-19 in the U.S. Capitol Washington, DC, May 11, 2021.

Greg Nash | Swimming pool | Reuters

The Senior Medical Advisor to the White House, Dr. Anthony Fauci said Tuesday that safety and efficacy data on combining a primary treatment for Covid vaccines from one manufacturer with boosters from another could be available within the next two weeks.

Although the Centers for Disease Control and Prevention approved Pfizer’s boosters for the elderly and the medically vulnerable on Friday, only recipients of the first two doses of Pfizer are eligible for the third injection. But the National Institutes of Health are about to complete studies mixing boosters and starting doses from Pfizer, Moderna and Johnson & Johnson, Fauci said at a Covid briefing at the White House.

“As with everything we do, they have to be submitted to the FDA for regulatory approval,” said Fauci of the so-called mix-and-match studies. “So you don’t want to be ahead of the FDA, but at least that’s where the data is now.”

Johnson & Johnson’s mix-and-match study data could be in within a week, while Pfizer’s study could be completed by mid-October. Moderna’s mix-and-match study data is already available, Fauci added.

Pfizer and Moderna’s vaccines use mRNA technology to fight Covid, while J & Js use an adenovirus to boost the body’s immune response. The ability to mix and match vaccines and booster vaccinations could give vaccine recipients more flexibility in choosing a third vaccination to bolster declining immunity from their starting doses.

Fauci’s comments came just days after NIH Director Dr. Francis Collins said the agency is still reviewing the results of combining starting doses and boosters from different vaccine manufacturers. Collins added that Moderna and J&J are weeks away from the CDC and FDA evaluating their boosters.

The NIH announced the start of its mix-and-match vaccine studies on June 1, which included approximately 150 adults vaccinated with Pfizer, Moderna, or J&J. Participants received a booster dose of another third dose approximately three to four months after receiving their initial vaccination schedule.


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