WASHINGTON — The Food and Drug Administration on Tuesday approved booster shots of the Pfizer-BioNTech vaccine for children ages 5 to 11, the latest in a series of actions designed to bolster the dwindling protection against infection from the coronavirus vaccines.
More than eight million of the 28 million children in that age group in the United States have received two vaccinations and are now eligible for the additional dose at least five months after their second injection. The Centers for Disease Control and Prevention will most likely recommend the booster dose after an advisory committee of outside experts meets Thursday to discuss it.
That would make all Americans 5 and older eligible for a booster shot. But booster uptake has been much slower than public health experts had hoped; many parents have been reluctant to vaccinate children in this age group at all.
Although they have been eligible for Covid injections since November, only 29 percent of 5- to 11-year-olds have received two doses. Another 6 percent have received one injection.
In a statement, Dr. FDA Commissioner Robert M. Califf said: “While it has largely been the case that Covid-19 is less severe in children than in adults, the Omicron wave has caused more children to become ill with the disease and inclusion in hospital, and children may also experience longer-term effects, even after initially mild illness.”
Some experts have suggested that because children aged 5 to 11 were given a much lower starting dose than older children or adults, they especially need a booster. A study by New York researchers found that for children ages 5 to 11, the effectiveness of the Pfizer vaccine against infection fell to 12 percent from 68 percent four to five weeks after the second dose.
Another CDC study found that two doses of Pfizer reduced the risk of Omicron infection by 31 percent in those 5 to 11, compared with a 59 percent reduction in risk in those 12 to 15. Dr. Peter Marks, the FDA’s chief vaccine regulator, said that “Emerging data suggest that vaccine efficacy against Covid-19 decreases after the second dose of the vaccine” in all age groups.
The newly approved booster dose is as strong as the first two injections. In a press release on Tuesday, Pfizer said the clinical trial data showed the additional injection triggered a strong immune response in the age group, generating neutralizing antibodies against both the Omicron variant and the original version of the virus.
The FDA said the safety of the dose was being assessed in about 400 children. The most commonly reported side effects were pain, redness, and swelling at the injection site, as well as fatigue, headache, muscle or joint pain, and chills and fever.
In a press release, Pfizer said the side effects were similar to those of the first two doses.