COVID vaccine prevents 40% of Omicron hospital stays in teens, 68% in kids

The effectiveness of two doses of the Pfizer/BioNTech COVID-19 vaccine against hospitalization for infections with the highly transmissible Omicron variant was 40% among adolescents 12 to 18 years and 68% among children aged 5 to 11, finds a test-negative study published yesterday in the New England Journal of Medicine (NEJM).Led by the Centers for Disease Control and Prevention's (CDC's) COVID-19 Response Team, the study involved 1,185 COVID-19 patients admitted to 31 US pediatric hospitals and 1,627 controls aged 5 to 18 years admitted for other indications.

The 918 adolescents were enrolled from Jul 1 to Dec 18, 2021 (Delta variant era) and from Dec 19, 2021, to Feb 17, 2022 (Omicron era).The 267 children aged 5 to 11 were enrolled only during the Omicron period because the Pfizer vaccine wasn't authorized for that age-group until October 2021.

Owing to insufficient numbers of severely ill patients in this age-group, VE against critical illness—defined as those who required life support, such as mechanical ventilation—couldn't be evaluated.92% effective in teens for up to 10 monthsAmong the 1,185 total hospitalized patients, 1,043 (88%) were unvaccinated, 291 (25%) required life support, and 14 (1.2%) died.Of 12- to 18-year-olds, 87% were unvaccinated, 27% were critically ill, of whom 2% needed extracorporeal membrane oxygenation (ECMO) (93% of them were unvaccinated), and 13 died.

Among children 5 to 11 years, 92% were unvaccinated and 16% needed life support (90% unvaccinated), including 2 who required ECMO and 1 who died.Vaccine effectiveness (VE) of two doses of the Pfizer vaccine given at least 14 days earlier against COVID-19 hospitalization among 12- to 18-year-olds in the Delta-dominant period was 93% (95%