The SARS-CoV-2 vaccine from Pfizer and BioNTech is less effective at preventing infections among children between the ages of 5 and 11 years old than among adolescents or adults, NPR reports.
It adds that a new analysis by New York State Department of Health researchers examined data on 1.2 million vaccinated children and adolescents. As they report in a preprint posted to MedRxiv, the researchers found that vaccine effectiveness for the 5-to-11-year-old group fell from 68 percent to 12 percent, as compared to 66 percent to 51 percent among 12-to-17-year olds, during the analysis time.
"It's disappointing, but not entirely surprising, given this is a vaccine developed in response to an earlier variant," senior author Eli Rosenberg from the NYS health department tells the New York Times. "It looks very distressing to see this rapid decline, but it's again all against Omicron."
Children and adolescents, NPR notes, receive different dosages of the vaccine, with the younger group receiving a 10-milligram dose and the older group receiving a 30-milligram dose, the same as adults. This, the Times notes, suggests that more data is needed to find the best dosage, timing, and number of doses for children.
The preprint authors add that vaccination was still protective against severe disease among children.