FDA advisers to review, likely recommend COVID-19 vaccines for young children this week

A federal advisory panel is likely this week to recommend two COVID-19 vaccines for the youngest children, as well as a second option for older kids whose access has been limited to Pfizer-BioNTech shots.

According to detailed information made public Friday and Sunday, Food and Drug Administration staff reviewed safety and effectiveness data for the Moderna vaccine for people ages 6 months to 17 years and for the Pfizer-BioNTech vaccine for children ages 6 months through 4 years.

The review was positive, raising no new safety issues or concerns about trial data, most of which had been released by the companies.

An FDA expert advisory panel will hold all-day meetings Tuesday and Wednesday to discuss the data, but the staff review suggests that there will be no major surprises and that the panel will recommend authorization of both vaccines.

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If that happens and the FDA commissioner signs off on the shots, the Centers for Disease Control and Prevention will follow the same process, and a different expert advisory panel will do a review Friday and Saturday. The CDC director would have to endorse the vaccines before the companies would be allowed to provide them.

The Biden administration said that if the vaccines are authorized this week, they would become available as soon as June 21 (a day after the federal Juneteenth holiday) at pharmacies, pediatricians' offices, libraries, children's museums, health centers and other outlets.

The federal government pre-purchased vaccine doses, which will be provided at no cost to families.

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Advocates are eager for vaccines to finally be extended to young children, the only major group of Americans left unprotected by vaccines.

"This moment is bittersweet," said Fatima Khan, co-founder of Protect Their Future, a grassroots group of physicians, parents and activists. "We're grateful to access a safe vaccine but also troubled by how long it took. … We must learn from this experience and fix root bureaucratic issues that caused the delays so that our children are never left behind again."

The only vaccine available for children has been Pfizer-BioNTech's, authorized for those 5 and up. Traditionally, drugs and vaccines are studied first in adults, then in adolescents and progressively younger children, moving down in age as safety and effectiveness are proved in older groups.

Babies younger than 6 months are not expected to receive a COVID-19 vaccine. Instead, vaccination during pregnancy, which has been safe, passes on protection that lasts for about the first six months of life.

Companies determined the most effective doses of COVID-19 vaccines for each eligible age group, while minimizing side effects.

Pfizer-BioNTech offers adults and adolescents a two-dose initial vaccine series, with 30 micrograms of active ingredients in each shot. Children ages 5-11 receive 10 micrograms of the vaccine, and the youngest children would get a 3-microgram dose.

Pfizer and its German partner, BioNTech, found that two doses were not adequately protective against the omicron variant of the coronavirus, so they asked the FDA and CDC to authorize a three-dose series for children ages 6 months through 4 years old. Older children are authorized to receive a booster dose to protect against the latest variants.

Adults get two 100-microgram doses of the Moderna vaccine, which is based on the same mRNA technology as Pfizer-BioNTech's, for their initial series. The company proposed the same dosage for teens, two 50-microgram shots for younger children and two 25-microgram doses for the youngest children.

Moderna tested its vaccine in two doses only, and it appears less effective in the youngest children.

On Tuesday, the FDA advisory panel, called the Vaccines and Related Biological Products Advisory Committee, will review data on Moderna's vaccine for children 6 to 17.

On Wednesday, the panel will decide whether to recommend Moderna and Pfizer-BioNTech's vaccines for children as young as 6 months.

Vaccine side effects, dosage for children and what studies have found

Vaccine side effects in the youngest age groups were similar to those in older children, including short-term fever and redness at the injection site, studies showed.

Neither vaccine trial in young children found any cases of allergic reactions to the shots or myocarditis, the swelling of the heart muscle occasionally seen among adolescent boys and young men after vaccination.

In the Pfizer-BioNTech trial, three shots – the third given at least eight weeks after the second – protected more than 75% of children ages 6 months to 2 years and 82% of those ages 2 to 5, and there was no significant increase in side effects. The trial included about 4,500 children in five countries; twice as many participants got the active vaccine than got a placebo.

The Pfizer-BioNTech trial had been designed to wait for results until 21 children in either the placebo or active vaccine group contracted COVID-19. Although cases have risen in recent weeks, only 10 had tested positive for the coronavirus this month, so technically, the effectiveness results are considered preliminary.

In Moderna's trial of 6,700 children ages 6 months to under 6, company researchers found that two 25-microgram doses led the children to develop levels of virus-fighting antibodies comparable to young adults who received two full-strength shots.

In the study, which took place during the omicron wave, researchers found the vaccine was 51% effective among children 6 months to under 2 and 37% effective among children 2 to under 6.

Among older children, a 50-microgram dose appeared to be safe and effective, according to company data and the FDA analysis.

Moderna filed a year ago for authorization of its vaccine in adolescents, but the FDA held the application, awaiting more information on the risks of myocarditis after vaccination. The committee will review more recent data and decide whether the benefits of the vaccine outweigh the risks of myocarditis in that age group.

Teens and young adults, particularly males, appear to be at the highest risk for this side effect, though it is generally milder than the myocarditis caused by infection with COVID-19.

5 million doses of each vaccine available by June 21

The FDA advisory panel is likely to make a recommendation at the end of each day's meeting: Tuesday on Moderna's vaccine for children ages 6-17 and Wednesday on both vaccines for young children.

Administration officials said last week they started accepting state and local orders for the shots and expect to have 5 million doses each of Pfizer-BioNTech and Moderna vaccines for young children available on June 21 and millions more soon thereafter.

"If the FDA and the CDC recommend these vaccines, this would mark an important moment in the pandemic," Dr. Ashish Jha, the White House COVID-19 response coordinator, said at a news conference last week. "It would mean that for the first time, essentially every American – from our oldest to our youngest – would be eligible for the protection that vaccines provide."

Contributing: Adrianna Rodriguez

Contact Karen Weintraub at kweintraub@usatoday.com.

Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.

This article originally appeared on USA TODAY: COVID vaccine for kids: FDA panel likely to recommend Pfizer, Moderna