Despite efficacy doubts, FDA advisers endorse Pfizer, Moderna COVID shots for preschoolers

An FDA advisory committee of independent specialists has recommended by a unanimous vote that the Pfizer and Moderna COVID-19 vaccines be sanctioned for preschoolers.

While the blessing sets up the vaccines for long-awaited FDA authorizations, questions remain about how effective the shots will be given the rapidly evolving virus.     

The panel based its recommendation on clinical data gathered early this year when the omicron variant was predominant. Months later, the BA.4 and BA.5 subvariants of omicron are quickly changing the COVID landscape. CDC data show that the new strains account for 21% of new infections. Just five weeks ago, BA.4 and BA.5 accounted for just 1% of cases.

“We have to make decision based on the best data we have, which is always going to be old data in an outbreak that’s constantly moving,” Paul Rubin, M.D., an infectious disease expert at Harvard, told the committee.

Early research indicates that BA.4 and BA.5 infections are more transmissible but do not cause more serious illness.

“We’re really trying to predict the future,” Paul Offit, M.D., of the Children’s Hospital of Philadelphia and a committee member, told The New York Times. “This is a problem.”

The FDA nods would allow children ages 6 months to 5 years to get the Pfizer shot, while kids ages 6 months to 6 years could receive the Moderna vaccine. The approvals would make nearly 20 million children in the U.S. eligible.

While older adults have been much more vulnerable to serious COVID infection and death, more than 200 children age 6 months to 4 years have died of the virus in the U.S. 

“We have to be careful that we don’t become numb to the number of pediatric deaths because of the overwhelming number of older deaths here,” Peter Marks, M.D., Ph.D., of the FDA, told the committee.

For younger children, Moderna’s vaccine is a two-dose series, while Pfizer’s requires three shots for full vaccination, the third dose spaced two months after the second. Pfizer’s shot is a 3-microgram dose, which is 1/10 of the dose for adults.

Some in the FDA committee believe the Pfizer dose is too weak and stressed the need to complete the three-dose series.

“I do worry that parents aren’t necessarily going to know that after two doses, they may not be protected at all and will engage in the kind of activity that would put their child at risk,” Offit told the committee.

Moderna’s shot for young kids is a 25-microgram dose, which is a quarter of the size adults receive. The company has said it's investigating the effect of a third dose for preschoolers.

An FDA authorization would finally give infants and toddlers a chance to be vaccinated—18 months after the shots were approved for adults.

“There are so many parents who are absolutely desperate to get this vaccine, and I think we owe it to them to give them the choice,” said Jay Portnoy, M.D., of Children’s Mercy Hospital in Kansas City, Missouri.

Moderna wants to take the age even lower. Wednesday, the company revealed that it will conduct a trial of its vaccine on babies 3 to 6 months of age. The BabyCove study aims to enroll 700 infants starting in September.

The recommendation came a day after the advisory committee signed off on Moderna’s vaccine for children ages 6 to 17 years. The company has struggled for months to gain a green light for this age group because of fears that its shot increased the risk of heart inflammation.