US health regulators are seeking additional coronavirus booster shot data from Moderna Inc., as the Biden administration expects to begin a widespread booster campaign later this month with only the Pfizer Inc.-BioNTech vaccine, people familiar with the matter say.
Moderna announced Friday that it had “completed its submission of data to the Food and Drug Administration for authorization of boosters.”
The FDA has been seeking more data as Moderna’s submission rolled in, the people added.
In particular, the FDA is looking for more information on the efficacy of a 100-microgram dose — the same as the first two shots people received — not just the 50-microgram booster submitted by Moderna as a potential booster, one of the people said.
Whether the apparent impasse will spark a lengthy delay, or ultimately be resolved, is unclear.
The FDA will now pore over the Moderna submission. The agency has been pressing for data on a 100-microgram booster as it weighs its next steps.
The Biden administration announced that it would offer boosters beginning Sept. 20, but the baseline expectation is now that it will begin with only the Pfizer-BioNTech shot at that point, the people said. Moderna is poised to follow a couple weeks later, one of them said.
The FDA and the Department of Health and Human Services did not immediately respond to requests for comment. The White House referred inquiries to HHS.
“We consider our submission complete, said Kate Cronin,” a Moderna spokeswoman. “We can’t comment on the FDA reviewal portion and what that will entail.”
The company on Friday announced that it had “completed its submission” two days after saying that it had filed initial data to the FDA.
Moderna also submitted booster-shot data to the European Medicines Agency for a conditional marketing approval, the company said in a statement late Friday.