A medical worker prepares the Pfizer-BioNTech Covid-19 vaccine booster in Hartford, Connecticut, in January.

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A medical worker prepares the Pfizer-BioNTech Covid-19 vaccine booster in Hartford, Connecticut, in January. / AFP via Getty Images

A highly anticipated meeting of expert advisers to discuss whether to recommend the use of the Pfizer-BioNTech COVID-19 vaccine for young children has been postponed.

The Food and Drug Administration said Pfizer told the agency that new data have recently emerged regarding its emergency use authorization request for the Pfizer vaccine in children 6 months through 4 years of age.

The agency said its preliminary assessment and need to allow more time to evaluate additional data led it to postpone the meeting scheduled for Tuesday, Feb. 15.

"We believe additional information regarding the ongoing evaluation of a third dose should be considered as part of our decision-making for potential authorization," FDA officials said in a statement.

Pfizer and BioNTech were applying for authorization for the first two shots, given three weeks apart, of an expected three-shot regimen while the companies worked on collecting data for the third dose.

But a statement from the companies showed that they had changed course. The decision means access to a COVID-19 vaccine for the youngest children will be delayed.

"Given that the study is advancing at a rapid pace, the companies will wait for the three-dose data as Pfizer and BioNTech continue to believe it may provide a higher level of protection in this age group," the statement said. "The companies expect to have three-dose protection data available in early April."

The FDA needs time to review new data

"At this time, it makes sense to wait to evaluate a third dose before taking action," said Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, in a briefing with reporters Friday afternoon. He said the flood of cases related to the omicon surge had caused new data to come in rapidly and that the agency needs time to analyze it.

In young kids, three shots appear necessary to achieve the full immunization. The third shot, given eight weeks after the second, isn't a booster. The companies said in December that two shots for children older than age 2 but under 5 didn't prompt the expected protection.

The vaccine dose under regulatory review is 3 micrograms per shot, a tenth of the amount given to adults and teenagers. For children ages 5-11, the dose is 10 micrograms.

The scheduled meeting would have looked at only the first two shots in the immunization series not the data for all three shots. That was an unorthodox regulatory move that might have gotten the authorization and vaccination moving faster. Pfizer and BioNTech said in a Feb. 1 statement that they applied for authorization this way because of the "urgent public health need."

The FDA said it would do what it could to make a decision quickly about expansion of the Pfizer vaccine for the youngest kids.

"We realize the need for a vaccine for COVID-19 — even with the drop in cases," FDA's Marks said in the media briefing. "We will do our part to move ahead as fast as we can."

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