A new study by the Centers for Disease Control and Prevention (CDC) and Abt Associates shows that the Pfizer-BioNTech COVID-19 vaccine is moderately effective against the Omicron variant for children ages 5-15. It reduced the risk of infection by 31% for children 5-11 and by 59% for children 12-15.
The Pediatric Research Observing Trends and Exposures in COVID-19 Timelines (PROTECT) study, which used real-world data, found that the vaccine was moderately effective against Delta and Omicron infection and that vaccinated children spent less time sick in bed than unvaccinated children with an Omicron infection.
The study looked at 1,364 children in Arizona, Florida, Texas, and Utah who submitted weekly nasal swabs and surveys from July 2021 through February 2022, regardless of whether they had symptoms.
“Without regular weekly testing you will miss many infections, particularly for kids, who often have mild symptoms,” said Lauren Olsho, the PROTECT study’s principal investigator. “Other pediatric vaccine effectiveness studies relied on lab testing data or health records and generally captured only cases where a child had symptoms and received health care. With increased use of home rapid testing, studies like ours are needed to provide more comprehensive information on rates of infection and vaccine effectiveness.”
The CDC noted that the PROTECT study is among the largest studies with routine weekly COVID-19 testing, regardless of COVID-19-like symptoms. The CDC also said that the study may provide greater understanding of factors that can affect infection risk, such as socio-demographic characteristics, health information, frequency of close social contact, mask use, location, and local virus circulation. This insight provided more accurate estimates of vaccine effectiveness for preventing symptomatic or asymptomatic COVID-19 infection following a two-dose Pfizer-BioNTech mRNA vaccination series.
Researchers cautioned that the vaccinated children wore masks more often at school than the unvaccinated children, which could have affected the results. In addition, despite the sample size and diverse locations, it’s not clear if the results are generalizable for all 50 states.
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