Fresh data shows that Pfizer’s COVID vaccine is far less powerful at preventing infection among children ages 5 to 11 than teens, a finding that could leave some parents of younger children worried.
The vaccine — the only one authorized for that age group in the United States — does prevent severe illness in young children, according to data collected during the Omicron surge. But it offers almost no protection against coronavirus infection, even within a month after full immunization, according to researchers.
Why is the vaccine less powerful?
One reason may be that children receive one-third the dose given to older children and adults, researchers and federal officials who have reviewed the data told The New York Times. The disappointing findings follow recent trial results that showed the vaccine performed poorly in children aged 2 to 4, who received an even smaller dose.
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“It’s disappointing, but not entirely surprising, given this is a vaccine developed in response to an earlier variant,” says study leader Eli Rosenberg, deputy director for science at the New York State Department of Health. “It looks very distressing to see this rapid decline, but it’s again all against Omicron.”
The findings were published in the preprint server medRxiv, and have not yet been peer-reviewed.
Protection against severe disease
Despite the lackluster results, Rosenberg and other public health experts say they recommend the shot for children because the vaccine continues to guard against severe disease in this group.
“We need to make sure we emphasize the doughnut and not the hole,” Dr. Kathryn Edwards, a pediatric vaccine expert at Vanderbilt University, told the Times.
In the latest study, Rosenberg and his colleagues analyzed data from 852,384 fully vaccinated children aged 12 to 17 and 365,502 fully vaccinated children aged 5 to 11 between the middle of December and the end of January.
The vaccine’s effectiveness against hospitalization declined to 73 percent from 85 percent in the older children. In the younger children, effectiveness dropped to 48 percent from 100 percent. But because very few children were hospitalized, these estimates have wide margins of error, the Times said.
The vaccine’s performance against infection was even worse: It dropped to 51 percent from 66 percent in older children, while it