WASHINGTON – The Food and Drug Administration on Friday released a preliminary schedule to decide whether to approve a coronavirus vaccine for the youngest children in the United States, and announced that June 8 is the earliest date it will present data to its external advisors for a recommendation.
The nation’s 18 million children under the age of 5 are the only group that has not yet qualified for vaccination against the coronavirus.
The agency said it understood the urgency of protecting that group and that it would act quickly “if the data supports a clear path forward after our evaluation”[ads1];.
The FDA released a packed June plan, setting aside three days for the external advisory committee to review applications for pediatric vaccines from Moderna and Pfizer-BioNTech, and another day to debate and presumably vote on proposals to update existing vaccines so that they work better against a variety of coronavirus variants. The dates are preliminary, the agency said, because the companies have not yet completed the applications for emergency authorization.
The agency’s release of a schedule came after some critics raised concerns that it delayed the action on Moderna’s application to compare it with data from Pfizer, which is not expected in its entirety until June. FDA Commissioner Robert M. Califf said that was not the case in interviews Thursday and Friday.
“Categorically, there is no reason for the FDA to wait,” he told Andy Slavitt on the podcast “In the Bubble.” In an email response to questions, Dr. Peter Marks, who oversees the agency’s vaccine regulation, said regulators “will not stop going on any request just to synchronize things.”
Moderna said Thursday that they had asked the FDA to approve its vaccine for children under the age of 6, and said the clinical study showed that the vaccine was safe and provided an antibody response comparable to adults ages 18 to 25. It met the trial’s success criteria. It said the vaccine appeared to be 51 percent effective against symptomatic infection among those younger than 2, and 37 percent effective among those 2 to 5.
These efficacy rates are far below those of previous clinical trials conducted by both Moderna and Pfizer before the highly transmissible Omicron variant appeared. Omicron and its sub-variants have proven far better at avoiding protection against antibodies that make up the immune system’s first line of defense against infection.
Because there were no cases of serious illness or hospitalization among any of the trial participants, it was not possible to assess how well the vaccine protects against Covid’s worst outcome.
Moderna said they would complete the submission of data to the FDA by May 9. Pfizer and BioNTech are expected to complete the application to vaccinate children under the age of 5 in June. Vaccine regimens are different: Moderna suggests two doses that use a quarter of an adult dose. Pfizer and BioNTech are working on a three-dose regimen, with one-tenth of the adult dose.
Pfizer’s vaccine is already authorized for all 5 years and older, while Modern’s shots are limited to adults. Moderna has previously requested authorization for its vaccine for children between 6 and 17 years of age. The company said it plans to submit data that supports and updates these requests in about two weeks.
The FDA seems to want to consider Moderna’s applications to vaccinate several age groups at the same time. Dr. Marks testified at a Senate hearing this week that it takes more time to consider applications that cover a wider range of the population.
In that case, that attitude can trigger criticism. “It would definitely make the message a little bit easier: ‘Here’s this vaccine. It’s now available to all children,” said Dr. Jesse L. Goodman, a former FDA chief researcher, in an interview Thursday.
But he added: “The Pfizer vaccine is available for the older children. This younger group right now is the big unmet need. I do not think there would be anything wrong with approving the vaccine for the younger ones first, if they were ready.”
The agency set a June 28 deadline for the advisory committee to consider how best to update existing vaccines. Researchers working for the National Institutes of Health and vaccine manufacturers have struggled to try to redesign the vaccines so that they are more effective against newer virus variants. Federal health authorities have said they must select one or more revised versions by June to produce doses by the fall, when they expect the coronavirus to re-emerge.
The agency also said it plans to present vaccine data June 7 from Novavax, which has developed a vaccine using a more conventional approach than the Pfizer-BioNTech and Moderna shots that have now been used to inoculate hundreds of millions of Americans.
These vaccines are based on newer messenger RNA technology, while Novavax’s vaccine is protein-based. Protein-based vaccines have been used for decades and generally have a strong track record of safety and mild side effects.
It is not clear what role the Novavax vaccine, if approved, will play in the country’s vaccination program. However, some experts suggest that people who are hesitant to take Moderna or Pfizer BioNTech pictures may be more willing to accept the more conventional Novavax doses. It is also possible that a protein-based vaccine may work well as a booster for Pfizer or Moderna shots.