WASHINGTON — The Food and Drug Administration laid out a tentative timetable on Friday for deciding whether to authorize a coronavirus vaccine for America’s youngest children, announcing that June 8 is the earliest date that it is going to present data to its outside advisers for a suggestion.
The nation’s 18 million children under 5 are the one group not yet eligible for vaccination against the coronavirus.
The agency said that it understood the urgency of protecting that group and that it will act quickly “if the info support a transparent path forward following our evaluation.”
The F.D.A. laid out a packed June schedule, setting aside three days for its outside advisory committee to contemplate the pediatric vaccine applications from Moderna and Pfizer-BioNTech, and one other day to debate and presumably vote on proposals to update existing vaccines so that they work higher against a variety of coronavirus variants. The dates are tentative, the agency said, because the businesses haven’t yet accomplished their applications for emergency authorization.
The agency’s release of a schedule got here after some critics raised concerns that it was delaying motion on Moderna’s application with a purpose to compare it with data from Pfizer, which will not be expected in full until June. The F.D.A. commissioner, Robert M. Califf, said that was not the case in interviews on Thursday and Friday.
“Categorically, there isn’t any reason for the F.D.A. to attend,” he told Andy Slavitt on the podcast “Within the Bubble.” In an emailed response to questions, Dr. Peter Marks, who oversees the agency’s vaccine regulation, said that regulators “is not going to delay moving forward on any request simply to synchronize things.”
Moderna said Thursday that it had asked the F.D.A. to authorize its vaccine for kids under 6, saying its clinical trial showed the vaccine was secure and produced an antibody response comparable to that of adults ages 18 to 25. That met the trial’s criterion for achievement. It said the vaccine seemed to be 51 percent effective against symptomatic infection amongst those younger than 2, and 37 percent effective amongst those 2 to five.
Those efficacy rates are far below those of earlier clinical trials conducted by each Moderna and Pfizer before the highly transmissible Omicron variant emerged. Omicron and its subvariants have proved much more adept at evading protection from antibodies that constitute the immune system’s first line of defense against infection.
Because there have been no cases of great illness or hospitalization amongst any of the trial participants, it was impossible to guage how well the vaccine protects against Covid’s worst outcomes.
Moderna said it will finish submitting its data to the F.D.A. by May 9. Pfizer and BioNTech are expected to finish their application to vaccinate children under 5 in June. The vaccine regimens are different: Moderna is proposing two doses, using one-fourth the strength of an adult dose. Pfizer and BioNTech are working on a three-dose regimen, at one-tenth the strength of the adult dose.
Pfizer’s vaccine is already authorized for everybody 5 years and older, while Moderna’s shots are limited to adults. Moderna has previously requested authorization of its vaccine for kids between the ages of 6 and 17. The corporate said it plans to submit data supporting and updating those requests in about two weeks.
The F.D.A. appears to want to contemplate Moderna’s applications to vaccinate several age groups at the identical time. Dr. Marks testified at a Senate hearing this week that it takes more time to review applications that cover a broader swath of the population.
In that case, that stance could trigger criticism. “That will surely make the messaging somewhat easier: ‘Here’s this vaccine. It’s now available for all kids,’” Dr. Jesse L. Goodman, a former chief scientist with the F.D.A., said in an interview Thursday.
But he added: “The Pfizer vaccine is out there for the older children. This younger group right away is the most important unmet need. I don’t think there could be something unsuitable with authorizing the vaccine for the younger ones first, in the event that they were ready.”
The agency set June 28 for the advisory committee to contemplate how best to update the present vaccines. Researchers working for the National Institutes of Health and vaccine manufacturers have been racing to try to revamp the vaccines so that they are simpler against newer virus variants. Federal health officials have said they should select a number of revised versions by June to fabricate doses by the autumn, once they expect the coronavirus to resurge.
The agency also said it plans to present vaccine data on June 7 from Novavax, which has developed a vaccine using a more conventional approach than the Pfizer-BioNTech and Moderna shots which have now been used to inoculate a whole lot of thousands and thousands of Americans.
Those vaccines are based on newer messenger RNA technology, while Novavax’s vaccine is protein-based. Protein-based vaccines have been used for a long time and usually have a powerful track record of safety and mild uncomfortable side effects.
It will not be clear what role the Novavax vaccine, if authorized, would play within the nation’s vaccination program. But some experts suggest that people who find themselves hesitant to take the Moderna or Pfizer-BioNTech shots is likely to be more willing to simply accept the more conventional Novavax doses. It’s also possible that a protein-based vaccine might work well as a booster to Pfizer or Moderna shots.
