Health experts advising U.S. health regulators backed giving Covid-19 vaccines from Pfizer Inc. and BioNTech SE and from Moderna Inc. to children as young as 6 months old.
The panel voted 21 to 0 in a pair of votes on Wednesday in support of expanding access to the vaccines.
The positive recommendations will likely lead soon to expanding the U.S. Covid-19 vaccination campaign to the 19.6 million children from 6 months to under 5 years of age, one of the last groups of people in the U.S. waiting for shots.
The Food and Drug Administration, which doesn't have to follow the panel's recommendations but usually does, is expected to authorize the shots within days. Vaccinations could begin as early as June 21, according to the Biden administration.
Moderna's two-dose vaccine is up for the FDA's authorization in children 6 months to 5 years, while Pfizer's three-dose shot is under review for children 6 months to 4 years. The committee on Tuesday recommended that the agency expand use of Moderna's vaccine to older children up to 17 years.
"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 Dr. Jay Portnoy, a professor of pediatrics at Children's Mercy Hospital in Kansas City, Mo.
"The committee's support today is imperative to providing a critical tool for pediatricians, parents, and caregivers who eagerly await an option for children under five," Bill Gruber, Pfizer's senior vice president of vaccine clinical research and development, said in a statement.
The panel's endorsements came after FDA staff reviewed data from the companies' clinical trials, finding the vaccines were generally safe and effective. The FDA also found that both vaccines generated a robust immune response in the children, similar to those in young adults, which was the primary measurement in their clinical trials.
The Vaccines and Related Biological Products Advisory Committee includes physicians, infectious-disease scientists and other health experts. The panel meets regularly to consider vaccines and medicines under FDA review.
The FDA, which regulates medical products, must authorize the vaccines before they can be used outside trials. After the FDA's action, the Centers for Disease Control and Prevention, which offers guidance to doctors, pharmacies and vaccination sites, would set the policy for the youngsters to get the shots.
Many states and vaccination sites wait for the CDC's signoff before rolling out shots.
Children are generally at lower risk of developing severe Covid-19, though hospitalizations increased during the Omicron wave last winter. Health authorities have encouraged vaccinations of children eligible to get the shots to protect not only the children, but also adults.
Peter Marks, who heads the FDA's vaccines division, opened up the meeting saying the Omicron surge during the winter resulted in hospitalized children at a rate worse than even a terrible influenza season, and it was important that people "don't become numb" to pediatric Covid-19 deaths, even if they occur less frequently than in older people.
"Each child lost essentially fractures a family," he said.
While some parents of children under 5 years are eagerly waiting for shots for their young children, surveys suggest most parents are less enthusiastic.
About 18% of parents surveyed said they wanted to get their child vaccinated right away, while 38% said they plan to wait and see, according to a Kaiser Family Foundation poll conducted in April.
About 27% of parents don't plan to vaccinate their child at all, and 11% will do so only if they are required, according to the survey.
Some panel members acknowledged the relatively low risks to young children from Covid-19. Yet some said they understood why some parents were afraid their children could get a serious case requiring hospitalization.
"The lack of the vaccines for these young children has been a gap for many, and has really had an impact on their lives," said committee member Jeannette Lee, a professor of biostatistics at the University of Arkansas for Medical Sciences.
Other committee members said parents should know their children would need to get all three doses of the Pfizer vaccine before it can protect against Covid-19.
"People who've gotten two doses of that vaccine -- they have to know they're not protected and they're going to have to wait," said Dr. Paul Offit, professor of pediatrics at the Children's Hospital of Philadelphia. "I just hope parents understand that."
Pfizer's request for authorization is based on a 4,526-child study testing three doses of either a vaccine or placebo, with all doses coming between February and April, when the Omicron variant was prevalent in the U.S.
The results are preliminary. The FDA said in its staff review that the small number of children who became sick during the trial made it too soon to make definitive conclusions on the vaccine's effectiveness.
In its analysis, the FDA found the vaccine was about 80%-effective in preventing symptomatic Covid-19 among young study subjects through April 29.
For the youngest children in the study, side effects included irritability and drowsiness. Side effects in children 2 to 4 years old included pain at the injection site and fatigue, according to the FDA.
Pfizer settled on a dose of 3 micrograms -- one-tenth the dose that people 12 years and older receive -- in part because research found the lower dose to be more tolerable in youngsters and could help with adherence, Pfizer's Dr. Gruber told the panel.
"A third dose is required also for the 6 months to less than 5 years of age group to ensure a more robust protection against Covid-19 due to Omicron," Dr. Gruber said.
In February, the FDA delayed its review of Pfizer's vaccine for young children, because two doses of its vaccine weren't effective against Omicron. The delay allowed Pfizer to study a third dose.
The FDA's review of Moderna's vaccine was based on studies testing two doses of either the shot or a placebo in more than 6,300 young children.
Agency staff said Moderna's two-dose vaccine was 37%-effective for 2- to 5-year-olds and 51%-effective for children 6 to 23 months, in a study conducted when the Omicron variant was predominant.
The FDA said children 6 months to 11 years old had lower rates of side effects than adolescents and young adults, with the exception of fever, which was reported more frequently in the younger age groups.
While the studies of the Pfizer-BioNTech and Moderna vaccines didn't identify any cases of heart-inflammation conditions including myocarditis, the FDA panel is expected to discuss the issue.
The FDA has identified an elevated risk of the conditions in certain people, particularly males 12 to 17 years old.
The first two Pfizer doses are given three weeks apart, followed by a third dose at least eight weeks later. The two Moderna doses are given four weeks apart.
Moderna said it was studying boosters for its young vaccine recipients and that they would probably be needed. "I think all of us agree that these children are going to need a third dose at some point in time," said Jacqueline Miller, Moderna's senior vice president of infectious diseases.
