Pfizer and BioNTech pushed the pause button Friday on the process of authorizing its COVID-19 vaccine for the youngest children.
The companies said in a release that they want to wait until data becomes available on a third vaccine dose for children under 5, likely in early April.
They had originally said such data would become available in late March or early April and they would ask for vaccine authorization then.
But under pressure from the Food and Drug Administration, the companies submitted their data and requested authorization for the first two doses, saying they could add a third in the future.
Friday's news seems to reverse that and return to their earlier position.
An FDA advisory committee was planned for Tuesday to consider the request, but has been canceled. No new date has been set.
The companies "announced plans to extend their rolling submission" to the FDA, according to the release. The companies have been studying a low-dose version of their vaccine in children ages 6 months through 4 years.
Early results from the trial suggested that the vaccine was effective in the youngest children, but not in those ages 2 to 4, and the companies had said late last year that they expected a third dose of the 3-microgram vaccine would be needed to provide sufficient effectiveness to justify FDA authorization.
Then, officials said the trial had accumulated data faster than expected, because so many children were falling ill during the omicron surge.
Now, the companies say that their study is advancing at such a rapid pace, that they can wait for the three-dose data. "Pfizer and BioNTech continue to believe it may provide a higher level of protection in this age group," according to the release. "The companies expect to have three-dose protection data available in early April."
The FDA responded Friday by saying that waiting another six weeks made sense.
"Based on the agency’s preliminary assessment, and to allow more time to evaluate additional data, we believe additional information regarding the ongoing evaluation of a third dose should be considered as part of our decision-making for potential authorization," the FDA said in a statement.
The agency defended its interest in seeing two-dose data, saying that "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." Reviewing the data so far has been useful, the agency said, "but at this time, we believe additional information regarding the ongoing evaluation of a third dose should be considered."
In the meantime, the best way to protect young children is to have the adults around them get vaccinated and boosted, the agency said.
Protect Their Future, an advocacy group of physicians, parents and activists, decried the decision calling it in a statement, "a travesty for millions of families and children across the country."
The vaccines have been proven safe, the group noted, and "withholding them during the pandemic is unconscionable."
They called for the data and reasoning behind the decision to be shared. "Today, the FDA owes the data from the Pfizer trials to the millions of families they gave false hope to."