New data from the height of New York state's omicron surge suggests Pfizer's vaccine offers significantly less protection against infection in children ages 5 to 11 compared to older kids and adults.
Researchers at the New York State Department of Health analyzed data on 852,384 children ages 12 to 17 and 365,502 children ages 5 to 11 who were fully vaccinated between Dec. 13, 2021, and Jan. 30.
Health officials found Pfizer's vaccine — the only one authorized for use in kids ages 5 to 11 — protected young children against hospitalization but offered little protection against infection, even in the month after children were fully vaccinated.
Vaccine effectiveness against infection in young children fell from 68 percent to just 12 percent over the study period. In children ages 12 to 17, this figure fell from 66 percent to 51 percent.
One potential reason for the drop in vaccine effectiveness is that the COVID-19 vaccine dose for young children is one-third the dose for those 12 and up, researchers and federal officials who received the data told The New York Times.
"These results highlight the potential need to study alternative vaccine dosing for children and the continued importance [of] layered protections, including mask wearing, to prevent infection and transmission," researchers said.
Health experts still recommend that young children get vaccinated against COVID-19, as the research shows Pfizer's shot protects against severe disease.
The research was published Feb. 28 in the medical preprint server MedRxiv and has not been peer reviewed.