Outside advisers to the Food and Drug Administration voted unanimously on Wednesday to recommend that the agency authorize the Moderna and Pfizer-BioNTech coronavirus vaccines for very young children, a move that could clear the way for regulators to authorize both pediatric vaccines on an emergency basis later. this week.
Pfizer’s three-dose vaccine would cover children 6 months through 4 years old, while a moderna two-dose vaccine would cover children for 6 months through 5 years old. States already have millions of doses. Depending on what regulators do, White House officials have said the administration’s doses could begin on earnest on Tuesday.
The FDA has stated that clinical trial data from the companies shows that the safety and efficacy of each vaccine met the criteria in the age group.
More than two years into the pandemic, no vaccine has been authorized for children younger than 5 in the United States, an unmet need that has dismayed many parents. The FDA is expected to act on the recommendations promptly, followed by the Centers for Disease Control and Prevention later this week.
The panel’s advisors voted 21-0 to recommend authorization of both Moderna’s and Pfizer’s vaccines. “I know the death rate from Covid and young children may not be extremely high,” said Dr. Jay Portnoy, a professor of pediatrics at Children’s Mercy Hospital in Kansas City, Mo. But he said: “It’s absolutely terrifying for parents to have their child sick” or hospitalized.
“There are so many parents who are absolutely desperate to get this vaccine,” he added, “and I think we owe it to them to give them the choice.”
Both vaccines that the committee considered on Wednesday appeared significantly less effective against symptomatic infections than the adult vaccines when they were introduced. The FDA attributes that Omicron is far more adept at evading the vaccines’ defenses against infection than the original version of the virus.
Given the waning of protection observed in adult recipients and the rapid evolution of the virus, regulators have said that children who would get Pfizer’s and Moderna’s vaccines would most likely require a booster. That would mean Pfizer’s vaccine, developed with the German firm BioNTech, could wind up as four doses, while Moderna’s could have three.
Both Pfizer-BioNTech and Moderna’s vaccines neutralize levels of provoked, or virus-blocking, antibodies in children comparable to those in teens and young adults 16 to 25. Pfizer’s vaccine has been authorized for children 5 to 15 since last year, and regulators said it helped prevent hospitalization and deaths.
After two doses, Pfizer’s vaccine was only about 28 percent effective in preventing symptomatic infections in children aged 6 months to 4 years old. Pfizer has suggested the vaccine was 80 percent effective after a third dose, but the finding was based on only a subset of 10 cases out of the 1,678 trial participants. The trial protocol states that vaccine efficacy assessments are based on at least twice that in many cases; The small number of cases on which the efficacy was found was based on the constitution of a subject among committee members and regulators on Wednesday.
Dr. Doran Fink, a senior federal vaccine regulator, called Pfizer’s efficacy data preliminary. “We consider it to be imprecise and potentially unstable,” he said. “Exactly what the vaccine efficacy is after happy three needs further data.”
Moderna found its vaccine to be 51 percent effective in preventing symptomatic infections in children from 6 months to 2 years old, and 37 percent effective in children 2 through 5. Those results appear consistent with those reported in adults during the Omicron era, the FDA said. Still, immunization continues to offer strong protection against severe disease that leads to hospitalization and death.
Regulators and company officials spend part of the day discussing side effects by vaccines. The vast majority were mild and tolerated by clinical trials in children: irritability and crying, sleepiness, fatigue and loss of appetite. Smaller numbers of trial participants endured fevers, but they were consistent with the effects of other pediatric vaccines.
In younger age groups, fevers can be more debilitating and require more urgent medical attention, a dynamic that puts significant pressure on the manufacturers to calibrate dosing properly. Pfizer chose a dose at just one-tenth the strength of adult dosing, given in three shots; The first two are administered three weeks apart, with the third coming at least eight weeks after the second. Moderna used a quarter of the strength of its adult dosing, administered in two shots, four weeks apart.
Some difficult questions remain. Importantly, neither vaccine has been tested against circulating suburbanites 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 need to protect these children from Covid is great, said Dr. Peter Marks, the FDA’s top vaccine regulator, at the meeting. He added that hundreds of children had died of Covid, a rate he said “compares quite terribly” to pediatric deaths during a major influenza surge in 2009 and 2010.
June 15, 2022
Because of an editing error, an earlier version of this article was misstated when the Pfizer-BioNTech vaccine was authorized for different age groups in the United States. The vaccines were authorized for ages 16 and older in late 2020, not in 2021, when the vaccines were authorized for ages 5 to 15.