Dr.Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, makes opening statement at a Senate Committee on Health, Education, Labor and Pensions hearing to discuss federal response ongoing to COVID-19, at the United States Capitol in Washington, DC, May 11, 2021.
Greg Nash | Swimming pool | Reuters
White House chief medical adviser Dr Anthony Fauci said on Tuesday that the safety and efficacy data on the association of a primary Covid vaccine regimen from one manufacturer with boosters from another could be available in the next two weeks.
Although the Centers for Disease Control and Prevention on Friday cleared the Pfizer recall for the elderly and medically vulnerable people, only recipients of the first two doses of Pfizer are eligible for the third injection. But the National Institutes of Health are set to conclude trials that mix boosters and initial doses of Pfizer, Moderna and Johnson & Johnson, Fauci said during a White House briefing on Covid.
“Like everything we do, they have to go to the FDA for regulatory approval,” Fauci said of the so-called “mix-and-match” trials. “So you don’t want to get ahead of the FDA, but at least that’s where the data is right now.”
Data on the Johnson & Johnson mix-and-match study could be ready within a week, while Pfizer’s trial could be completed by mid-October. Data from Moderna’s mix-and-match study is already available, Fauci added.
Vaccines from Pfizer and Moderna use mRNA technology to fight Covid, while J & J’s uses an adenovirus to boost the body’s immune response. The ability to mix and match vaccines and boosters could give vaccinees more flexibility in choosing a third shot to boost waning immunity from their initial doses.
Fauci’s comments came just days after NIH director Dr Francis Collins said the agency was still reviewing the results of combining initial doses and boosters from separate vaccine manufacturers. Collins added that Moderna and J&J were weeks away from the CDC and FDA to evaluate their boosters.
The NIH announced the start of its mixed vaccine trials on June 1, which included about 150 adults vaccinated with Pfizer, Moderna, or J&J. Participants were boosted with a different third dose approximately three to four months after receiving their initial vaccination schedule.