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COVID-19 vaccines retained the ability to prevent deaths from COVID-19 in children and adolescents regardless of the dominant circulating variant, in a new study.

The vaccine's effectiveness against infection in the short term has been established, as has the waning effectiveness of the vaccine over time, wrote Juan Manuel Castelli, MD, of the Ministry of Health of Argentina, Buenos Aires, and colleagues, in the British Medical Journal.

However, data on the impact of vaccine effectiveness on mortality in children and adolescents are limited, especially during periods of omicron variant dominance, the researchers said.

In their new study, the researchers reviewed data from 844,460 children and adolescents aged 3-17 years from the National Surveillance System and the Nominalized Federal Vaccination Registry of Argentina, during a time that included a period of omicron dominance.

Argentina began vaccinating adolescents aged 12-17 years against COVID-19 in August 2021 and added children aged 3-11 years in October 2021. Those aged 12-17 years who were considered fully vaccinated received two doses of either Pfizer-BioNTech and/or Moderna vaccines, and fully-vaccinated 3- to 11-year-olds received two doses of Sinopharm vaccine.

The average time from the second vaccine dose to a COVID-19 test was 66 days for those aged 12-17 years and 54 days for 3- to 11-year-olds. The researchers matched COVID-19 cases with uninfected controls, and a total of 139,321 cases were included in the analysis.

Head over to Medscape to read the full story.