Federal regulators Thursday authorized an updated booster shot for Moderna’s coronavirus vaccine for young children, saying the inoculation would offer increased protection amid a wave of respiratory illnesses that is increasing peril to youngsters. It means that the youngest Americans will have access to variant-targeting boosters already available to older children and adults.
The Food and Drug Administration, in a statement, said children 6 months through 5 years old would be eligible for the booster - known as a "bivalent" shot targeting omicron subvariants BA.4 and BA.5 and the original version of the virus - two months after they have completed Moderna's two-dose primary series.
The agency also cleared an updated shot of the coronavirus vaccine by Pfizer and its German partner, BioNTech, for children 6 months through 4 years old. That bivalent shot, which also targets omicron, will be substituted for a third shot in the companies' initial series that currently aims exclusively at the original version of the virus.
The FDA in June authorized a two-shot series of the Moderna vaccine of 25 micrograms each for young children, and a three-dose regimen of the Pfizer-BioNTech vaccine of 3 micrograms each. Pfizer and BioNTech have said they chose a lower dose to minimize potential side effects.
The Centers for Disease Control and Prevention is expected to sign off on the updated shots shortly.
The government's latest effort to bolster protections is bumping up against an unwelcome fact: Only a small percentage of young children are vaccinated against the coronavirus. Less than 5 percent of children 4 and younger have completed an initial series of a coronavirus vaccine, and less than 10 percent have received even a first shot, according to the CDC.
The FDA's steps "won't have a lot of real world impact," said Peter Hotez, professor of pediatrics and molecular virology and microbiology at Baylor College of Medicine. "It's like arguing over how many angels can dance on the head of a pin."
But federal health officials, eyeing a rise in covid-19 cases and pediatric hospitalizations because of an array of respiratory germs, believed it was important to make updated shots available to the youngest age groups.
"More children now have the opportunity to update their protection against covid-19 with a bivalent covid-19 vaccine, and we encourage parents and caregivers of those eligible to consider doing so - especially as we head into the holidays and winter months where more time will be spent indoors," FDA Commissioner Robert M. Califf said in a statement.
The BA.4 and BA.5 subvariants, which were circulating widely this summer, have faded, and are responsible for less than 15 percent of cases, according to the CDC. They have been replaced by BQ.1 or BQ.1.1, which are causing more than 60 percent of cases in the United States.
Officials say the bivalent formulation will offer improved protection against the latest crop of omicron subvariants. Still, that shield is not foolproof: The latest mutants have proved adept at dodging some of the protective antibodies generated by even that shot.
Some vaccine experts are worried that the emergency authorizations could cause confusion among parents, especially those whose children have received the Pfizer-BioNTech vaccine. The bottom line is this: Children who are in the process of getting that vaccine's three-dose series, and have received only two shots, will get the bivalent vaccine, not the original shot, as their third inoculation.
But children who have received the three-shot primary series of the Pfizer-BioNTech vaccine will not be eligible immediately for a booster. The FDA is expected to review data for a bivalent booster for the Pfizer-BioNTech shots early next year. These children "would still be expected to have protection against the most serious outcomes from the currently circulating omicron variant," the FDA said.
The change comes as children's hospitals are under strain in the United States as they care for unusually high numbers of kids infected with RSV and other respiratory viruses. Doctors are worried the numbers will rise as the weather continues to get colder and families and friends gather for the holidays.
But the boosters have hardly been embraced, even by adults. The uptake of a bivalent booster has been lackluster, and the White House recently said it would launch a six-week push to increase booster rates among older people, communities of color and rural areas - all of which have disproportionately suffered severe disease and death during the coronavirus pandemic.
The Washington Post’s Lena H. Sun contributed to this report.