A three-dose COVID-19 vaccine regimen could replace the current two-dose regimen required to be considered fully vaccinated with Pfizer's and Moderna's mRNA shots, according to the White House chief medical advisor.
"From my own experience as an immunologist, I would not at all be surprised that the adequate, full regimen for vaccination will likely be three doses," Anthony Fauci, MD, White House chief medical advisor and director of the National Institute of Allergy and Infectious Diseases, said during a Sept. 1 White House COVID-19 briefing.
A growing body of research suggests vaccine protection wanes over time, indicating a need for booster doses. During the briefing, Dr. Fauci cited a recent real-world study from Israel that found adults who received a third dose of Pfizer's vaccine were 11 times less likely to contract a breakthrough infection after 12 days.
Preliminary data have indicated a third dose will induce a strong and lasting response. If that's the case when vaccine makers present data on booster doses to the FDA, a three-dose vaccine regimen could likely become standard, Dr. Fauci said.
The federal government has said it plans to start administering booster doses for all Americans who received two doses of Pfizer or Moderna's vaccine Sept. 20, though the plan is contingent upon FDA approval. The agency is still reviewing that information.
Pfizer started submitting data to the agency for booster dose approval Aug. 25, with Moderna doing the same on Sept. 1. Federal health officials on Sept. 2 told Jeff Zients, the White House COVID-19 response coordinator, that the U.S. should delay its planned rollout because the FDA may only have time to approve and recommend booster doses for those who received Pfizer's vaccine in time for the country's scheduled rollout.
The FDA on Aug. 12 amended the emergency use authorizations for Pfizer's and Moderna's COVID-19 vaccines, allowing immunocompromised people to receive a third dose, but not yet for the general population.