Washington, Mar 12 (IANS): Two doses of Pfizer-BioNTech Covid-19 vaccine greatly reduced the risk of Omicron infection among children aged five to 15, according to a study published by the US Centers for Disease Control and Prevention (CDC).

Children and adolescents aged five to 15 were tested for SARS-CoV-2 weekly, irrespective of symptoms, during July 2021 to February 2022, Xinhua news agency quoted the CDC as saying.

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

Two doses of Pfizer-BioNTech Covid-19 vaccine reduced the risk of Omicron infection by 31 per cent among children aged five to 11, and by 59 per cent among adolescents aged 12 to 15, according to the CDC study.

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 five to 11 years on November 2, 2021.