FDA advisory panel votes unanimously that Pfizer and Moderna shots be authorized for young children

For an archived version of a live blog about Wednesday’s FDA advisory panel hearing, click here. 

A panel of advisers convened by the Food and Drug Administration voted unanimously Wednesday to recommend that the Covid vaccines made by Pfizer-BioNTech and Moderna be made available to children as young as 6 months old.

The vote is not binding, but the FDA is likely to follow the recommendation, setting in motion a government effort to make the shots available and to get them into kids’ arms.

“I think what we’ve heard from a lot of the committee members … is the emphasis on a choice,” said Ofer Levy, director of the precision vaccines program at Boston Children’s Hospital and a member of the advisory panel. “A choice for families. They can partner with their pediatricians, [and] make the decision.”

Before families can start to avail themselves of the vaccines, though, an advisory committee for the Centers for Disease Control and Prevention needs to recommend the shots, too, and CDC Director Rochelle Walensky must accept the recommendation. The group meets Friday and Saturday, when the votes will be held.

During a packed day of discussions, the 21-person Vaccines and Related Biological Products Advisory Committee, or VRBPAC, which met virtually, listened to presentations from both drug companies and to the FDA’s own scientists, who reanalyzed company data. Panelists delved into concerns about potential side effects, which were largely seen as manageable, and issues with the strength of the evidence for the Pfizer vaccine, where a relatively small number of cases of Covid were used to estimate the vaccine’s efficacy. In the end, though they raised many different concerns, every panelist agreed that both vaccines should be made available.

One big factor for many of the panelists was that they felt the risk of Covid to children is larger than many people realize. During the pandemic, the panelists heard, there have been 442 deaths of children aged 0 to 4 from Covid. Interpretation of this figure differed though, with some experts pointing out this means that Covid is a leading cause of death in children; pediatrician Cody Meissner, on the other hand, noted a similar number are struck by lightning in a year.

An authorization of both the Moderna and Pfizer vaccines will represent a new challenge for public health officials, because the vaccines appear to be different from one another. One big difference is dose: The Moderna series appears to provide protection after two doses, while the Pfizer one appears to require three, with the third dose given eight weeks after the second.

“I think with two vaccines that have different dosing regimens it is going to be even more important that the public health education, the education of providers, is done very, very carefully,” said Archana Chatterjee, the vice president of medical affairs at the Rosalind Franklin University of Medicine and Science. “We are making choices between two different vaccines that have a little bit different profiles.”

Paul Offit, of Children’s Hospital of Philadelphia, noted that previously the Moderna and Pfizer vaccines appeared very similar, but this was not true for younger children. Several experts said that this might be because Pfizer and BioNTech chose a lower dose for children. In his presentation, William Gruber, a top Pfizer executive, said that the company thought that a vaccine that caused many side effects, such as fevers, would not be accepted by parents.

In fact, the Pfizer shot appears to cause less fever and fatigue than the Moderna one, although direct comparisons are not available. But it also didn’t show strong efficacy against the now prevalent Omicron variant in the youngest children. This led Pfizer to add a third dose to its study, but many children in the study had not yet received a third dose. That meant that the number of cases of Covid on which to judge the vaccine’s efficacy was small, leading some experts to say they were not confident in the figure.

Overall, though, based on the vaccine’s ability to generate antibodies against the SARS-CoV-2 virus, and the track record of the vaccines, panelists unanimously agreed that it would be effective.

Panelists also emphasized that the FDA and CDC would closely monitor any potential side effects for both vaccines. Levy pointed to the fact that another vaccine, from Johnson & Johnson, is hardly being used because of a link to a rare clotting disorder as evidence that the FDA and its advisers take the safety of these vaccines extremely seriously.