Federal regulators authorized a coronavirus booster shot Tuesday for school-age children, a key step toward making a third shot of the Pfizer-BioNTech vaccine available to 5-to-11-year-olds as cases rise nationally.
FDA Commissioner Robert M. Califf said in a statement that while covid-19 tends to be less severe in children, the wave of infections caused by the omicron variant has resulted in “more kids getting sick with the disease and being hospitalized, and children may also experience longer term effects, even following initially mild disease.” He said the agency was authorizing the booster to provide continued protection.
Advisers to the Centers for Disease Control and Prevention are scheduled to meet Thursday and are expected to recommend the booster, which was shown in laboratory tests to strengthen children’s immune defenses — particularly against the omicron variant.
The shot from Pfizer and its German partner, BioNTech, is the only vaccine available to children in this age group, and two shots have provided disappointing protection to children in this age group in real-world studies. Protection against infections and hospitalizations waned quickly in children.
Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, described the development as “welcome news. The data from the delta and omicron waves clearly show lots of kids between 5 and 11 years old are getting sick. It’s important that we vaccinate them, and clearly the third dose is going to be needed to provide adequate protection against omicron and its variants.”
Phil Krause, former deputy director of the FDA’s Office of Vaccines Research and Review, agreed.
“This is a population where the original vaccination doesn’t seem to have done as well as the original vaccine series have done in other age groups,” Krause said. He said it will be interesting to see if CDC advisers debate whether the booster should be given sooner, because some studies have suggested the two shots provided lower-than-expected protection to this age group.
Many experts believe the third shot does more than just top-off waning immunity; the shot also broadens the ability of the immune system to defend against variants, including omicron.
But the decision about whether a booster should be strongly recommended to all children may not be straightforward for every parent, said Walid F. Gellad, director of the Center for Pharmaceutical Policy and Prescribing at the University of Pittsburgh.
Most children have been infected with the coronavirus, according to a CDC study, and fully vaccinated children who have been infected may benefit little from an additional dose. That means parents may see a clear benefit to a booster if their child is at high risk of severe illness and hasn’t been infected. But parents may not see a benefit if their child is not at high risk and was infected with omicron this spring.
Companies are also developing and testing boosters tuned to fight two versions of the virus, including omicron, in hopes the shots will provide better protection going forward.
“We’re getting very late into the covid epidemic to be vaccinating with a vaccine based on the ancestral virus, the original virus,” Gellad said. “The other issue is that many kids have been infected — and two doses plus infection provides pretty good protection.”
The FDA said its decision was based on laboratory measurements of the immune responses in 67 children. A month after the booster dose, their levels of virus-blocking antibodies were higher than before the shot, the agency said. Pfizer’s trial includes 4,500 children in this age group.
The agency cleared the primary two-shot series for the age group last October. Since then, “emerging data suggest that vaccine effectiveness against covid-19 wanes after the second dose of the vaccine in all authorized populations,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research. He said the booster would help counter that, protecting children from the most severe consequences of the illness.
A third shot could help shore up children’s immune defenses, but the impact of a third shot will probably be limited. Only 28 percent of children in this age group are fully vaccinated, according to the CDC. More than 18 million children in the group have not received a single shot, despite vaccine being available to them since November.
Mary Rodrigues, who lives in Baltimore, said she was thrilled to hear the news about the booster. She has a 10-year-old son who is fully vaccinated and is eligible for a booster.
“I was in the car driving home listening to NPR and when I heard it, I said, ‘great!’” said Rodrigues, a nurse. She and her husband, a doctor, are “very pro-science and pro-vaccine. For us, it isn’t even a question, it is how soon can we do it.”
In January, the FDA authorized a booster for adolescents 12 to 15 years old.
Tuesday’s move may sharpen some parents’ frustration about the divide between children who are able to get a third shot and those who can’t. Children younger than 5 still lack access to any coronavirus vaccine. A top FDA official predicted in an interview that the first shots might become available in June, assuming data supports such a move.
In late April, vaccine maker Moderna asked the FDA for emergency authorization for its two-shot vaccine for children 6 months to 5 years old. Pfizer and BioNTech are expected to submit the full data on a three-dose regimen for children 6 months to 4 years old in coming weeks.
The FDA has set aside several dates — June 8, 21 and 22 — to meet with outside advisers from the Vaccines and Related Biological Products Advisory Committee to discuss vaccine applications for the youngest children.
The FDA also announced plans to meet June 7 with its advisers to talk about an emergency authorization request for a coronavirus vaccine made by Novavax for people 18 and older.
Novavax submitted an application for emergency use authorization in late January. The vaccine uses a protein-based technology, with some novel twists. Shots from Moderna and Pfizer-BioNTech are produced using a new messenger RNA technology.
In addition, the FDA said it will convene an advisory committee meeting June 28 to discuss whether the composition of coronavirus vaccines should be modified for use in a potential vaccination campaign this fall.
Many experts say vaccines for the general population should be reformulated to keep up with the changing virus, but the question of whether, when and how remains unresolved.