WASHINGTON — The only Americans still ineligible for coronavirus vaccines — infants, toddlers and preschoolers — appear to be on the brink of finally getting permission to receive them after a Food and Drug Administration advisory panel voted unanimously on Wednesday to approve the Pfizer – and Moderna vaccines recommended for the group.
The FDA appears poised to approve Moderna’s vaccine for children under 6 and Pfizer’s vaccine for children under 5 as soon as Friday. States have already ordered millions of doses, and White House officials have said the injections could be rolled out as early as next week.
The committee’s 21-0 votes came after a day-long review of clinical trial data and marked the end of a process that saw months of false starts and wiped out hopes for a vaccine for the youngest Americans. With the exception of the roughly 20 million children under the age of 5, everyone has had access to coronavirus injections for many months and is now eligible for booster shots.
The FDA and the Centers for Disease Control and Prevention jointly pushed for a positive recommendation, with the commission gushing 230 pages of data they said showed the vaccines were safe and elicited a strong immune response in children. Regulators also stressed that while young children are generally at low risk of serious illness from the virus, vaccinating the group would save lives.
“We have to be careful not to get stunned by the number of pediatric deaths because of the overwhelming number of elderly deaths here,” said Dr. Peter Marks, the FDA’s chief vaccine regulator. “The intervention we’re talking about here is one that we’ve accepted in the past to try to prevent deaths from flu,” he added.
CDC officials said more than half of young children hospitalized with Covid had no underlying medical conditions. During the winter Omicron wave, young children were hospitalized more often than older children and adolescents, and their illness was usually at least as severe. More than 200 children between the ages of 6 months and 4 years have died of Covid, according to death certificate data, one of the most conservative estimates.
The panelists, some of whom have treated hospitalized children for Covid and comforted terrified parents, seemed eager to spring into action.
“There are so many parents who are absolutely desperate to get this vaccine,” says Dr. Jay Portnoy, a professor of pediatrics at the University of Missouri-Kansas City medical school. “I think we owe it to them to give them the choice.”
dr. Arthur Reingold, an epidemiologist at the University of California, Berkeley, School of Public Health, said the nation is already vaccinating children against diseases “where the risk of a child dying or being hospitalized for those diseases was virtually zero.”
The CDC’s own panel of vaccine experts will consider the matter over two days this weekend. If that committee also makes a favorable recommendation, Dr. Rochelle P. Walensky, the agency’s director, made her decision, the final step in the process.
Neither vaccine has been tested against new subvariants circulating in the United States. The clinical trials were largely conducted when the Omicron variant prevailed. Two subvariants, BA.4 and BA.5, could become dominant within a month.
The virus is evolving so quickly that some panelists feared that the results of clinical trials on which their decisions were based were already outdated. “We’re really trying to predict the future,” said Dr. Paul Offit, a vaccine expert at Children’s Hospital in Philadelphia and an FDA panelist, in an interview. “This is a problem.”
But the panel’s main concern seemed to be whether Pfizer’s three-dose vaccine, which it developed with its German partner BioNTech, was effective enough. Pfizer has reported that two doses of its vaccine were only about 28 percent effective at preventing symptomatic illness; dr. Susan Wollersheim, an FDA reviewer, said the company’s data did not clearly show that two doses reduced the incidence of Covid.
Pfizer argued that three doses were 80 percent effective, but the finding was based on just 10 cases from a subset of 1,678 trial participants. and dr. Doran Fink, acting deputy director of the FDA’s Office of Vaccines, questioned the company’s estimate, describing it as “preliminary” and “inaccurate.”
Still, he said, based on the immune response data, the FDA was “very confident” that Pfizer’s vaccine, like Moderna’s, met the criteria for authorization for emergency use, requiring the benefits to outweigh the risks. But some panelists were clearly worried that parents would be misled.
dr. Amanda Cohn, a top CDC official and panelist, said she has no “any idea” what the efficacy rate after three doses of Pfizer will ultimately be, and officials shouldn’t embrace the 80 percent estimate.
Jeannette Y. Lee, a biostatistician at the University of Arkansas for Medical Sciences, raised another concern: that some parents might skip the crucial third dose for their children. “As we know, getting people for two is a struggle,” she said.
Pfizer officials said the data showed the vaccine’s effectiveness over time. “It’s not like there’s no efficacy at all,” says Dr. William C. Gruber, senior vice president at Pfizer.
For some parents, the bar is set low. Some of the more than 1,600 parents who responded to a DailyExpertNews question about living with an unvaccinated young child said they would accept any efficacy above zero to give their children some protection.
“To protect her from illness and possible death or lifelong hardship? Why is this a question?” wrote Cayla Miller, a mother in Swanville, Maine. “We’ve waited so long to protect our entire family. I almost lost my job and my mind to protect her.”
Scientists and federal officials have warned against a direct comparison of the Moderna and Pfizer vaccines. Not only did the companies conduct their clinical trials at different times, with different populations, but the dosage and regimens differ.
Pfizer has proposed a three-dose regimen with one-tenth the adult dose, with the first two doses three weeks apart and the third at least two months after the second. Moderna wants to offer two doses of vaccine, four weeks apart, at a quarter of the strength of the adult dose. Moderna’s adult dose is significantly stronger than Pfizer’s.
dr. Wollersheim of the FDA declined to answer when a panelist asked for a comparison of vaccine effectiveness in young children. But as some parents might do, some panelists tried to do their own matchup.
dr. Offit noted that Moderna’s efficacy data was slightly stronger than Pfizer’s: about 51 percent effective at preventing symptomatic infection in children 6 months to 2 years old and 37 percent effective in children 2 to 5.
Although protection against symptomatic infection was limited, he said, it was possible to predict that Moderna’s vaccine would ward off serious disease.
“I’m not so sure you can predict that with Pfizer’s vaccine,” he said. “I’m afraid they’re underdosed.”
Both vaccines produced levels of neutralizing or virus-blocking antibodies in children that were comparable to those seen in young adults. Pfizer’s vaccine has been approved for children ages 5 to 15 since last year, and regulators said it helped prevent hospitalization and deaths.
Still, both appear to be significantly less effective against symptomatic infection than the adult vaccines when introduced 18 months ago. The FDA said that was because Omicron proved much more adept at evading the vaccines’ defenses against infection than previous versions of the virus.
Given the evidence of diminishing potency over time, the FD.A. has said that young children who receive Pfizer and Moderna injections are likely to need booster injections, as do older recipients. That would mean that Pfizer’s vaccine could end up as four doses, while Moderna’s could be three.
Neither vaccine caused serious safety concerns. The vast majority of side effects were mild — irritability and crying, drowsiness, fatigue and loss of appetite. Recipients of Moderna’s vaccine seemed more likely to have a fever, but in line with those caused by other pediatric vaccines, the FDA said.
Federal health officials have said they expect many children under 5 to be vaccinated by pediatricians and primary care physicians, as opposed to older age groups. But uptake is expected to be low; children ages 5 to 11 were eligible for vaccination late last year, but only about 37 percent of them have received at least one dose.
Doses are packaged by the hundred to reach smaller practices and nationwide locations. The Biden administration has also promoted a network of other locations that would work to reach families, including pharmacies and children’s hospitals, while groups such as the Association of Children’s Museums and the National Diaper Bank Network will help with education efforts.
A topic of discussion among FDA panelists was how to address the many parents whose children have already acquired some natural immunity. Federal health officials this week presented data to the commission suggesting that more than two-thirds of children ages 1 to 4 have already been infected with the virus.
A Moderna official told the committee that the company’s trial found that young children who had contracted the virus and had been vaccinated had a higher degree of protection, a conclusion supported by external research.
dr. James EK Hildreth, a committee member and the president of Meharry Medical College in Nashville, noted that many children were infected “and have been doing just fine.”
“But for those parents who choose to do this, especially for those parents of children with underlying conditions,” he added, “this is a choice they should have.”
Emily Erdos reporting contributed.