WASHINGTON – Two doses of Pfizer-BioNTech COVID-19 vaccine greatly reduced the risk of Omicron infection among children aged 5 to 15, according to a study published by the U.S. Centers for Disease Control and Prevention (CDC) on Friday.

Children and adolescents aged 5 to 15 were tested for SARS-CoV-2 weekly, irrespective of symptoms, during July 2021 to February 2022, according to the CDC.

Approximately one half of Omicron infections in unvaccinated children and adolescents were asymptomatic, according to the CDC.

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The Pfizer-BioNTech mRNA COVID-19 vaccine was recommended by CDC’s Advisory Committee on Immunization Practices for adolescents aged 12 to 15 on May 12 last year, and for children aged 5 to 11 years on Nov. 2.