The Food and Drug Administration is delaying its planned Tuesday meeting of outside advisers to consider recommending Covid-19 vaccines for children under 5 years old after new data from Pfizer and BioNTech convinced regulators to wait for more information about the effectiveness of a third dose.
Peter Marks, director of the agency's Center for Biologics Evaluation and Research, declined to explain what new information prompted the decision.
The companies have been testing a third shot after announcing in December that trial data showed two doses produced an insufficient immune response in toddlers. But FDA asked them last month to begin submitting data to support emergency use authorization for the first two shots in the expected three-dose series as the Omicron variant sickened more children than at any other point in the pandemic.
"Given the recent omicron surge and the notable increase in hospitalizations in the youngest children to their highest levels during the pandemic so far, we felt it was our responsibility as a public health agency to act with urgency and consider all available options, including requesting that the company provide us with initial data on two doses from its ongoing study," acting FDA Commissioner Janet Woodcock and Marks said in a joint statement. "The goal was to understand if two doses would provide sufficient protection to move forward with authorizing the use of the vaccine in this age group."
The regulators suggested the interim data was insufficient to begin considering authorization of the vaccine before the trial of three doses is complete. Pfizer and BioNTech said in a statement they expect data on the three-dose regimen by early April.
"Being able to begin evaluating initial data has been useful in our review of these vaccines, but at this time, we believe additional information regarding the ongoing evaluation of a third dose should be considered," Woodcock and Marks said.
In a call with reporters, Marks did not say when the vaccine for children under 5 would be considered, but that FDA would act quickly once it has sufficient data. He repeatedly declined to describe specific data that spurred the agency's decision to postpone the meeting.
“I think we owe it to the parents of small children in the country to proceed in that matter," he said.
He added that it's "probably a safe assumption" that, by waiting for more data, FDA will be able to consider an emergency use authorization for the youngest children based on data from actual infections, rather than just measuring antibody levels and comparing them to older kids.
Marks defended the agency's decision to schedule the advisory committee meeting in the first place, arguing that the delay shows regulators are making calls based solely on the science.
“We take our responsibility for reviewing these vaccines very seriously because we’re parents as well, and in looking over these data, I think parents can feel reassured that we have set a standard by which we feel that if something does not meet that standard, we can’t proceed forward," he said. "So rather than having any issue of causing anyone to question the process, I hope this reassures people that the process has a standard."
