Two new observational studies detail Pfizer/BioNTech COVID-19 vaccine protection among US children and adolescents amid the Omicron variant surge, one finding 71% efficacy against infection after a third dose in 12- to 15-year-olds, and the second showing lower risks of infection and hospitalization in vaccinated youth aged 5 to 17 in New York state.
The studies were published late last week in JAMA.Three doses more effective than 2 in teensIn the first study, researchers from the US Centers for Disease Control and Prevention analyzed data from 74,208 drive-thru polymerase chain reaction (PCR) COVID-19 test results from children aged 5 to 11 years, and 47,744 tests from aged 12 to 15 from Dec 26, 2021, to Feb 21, 2022.
The tests were conducted by a single pharmacy chain at 6,897 sites in 49 states; Washington, DC; and Puerto Rico.The researchers compared the effectiveness of two Pfizer COVID-19 vaccine doses at least 2 weeks before testing with no vaccination in children, and two or three doses 2 or more weeks earlier in adolescents.
Overall, the study involved 30,888 positive tests and 43,209 negative tests from children aged 5 to 11 and 22,273 positive tests and 25,471 negative tests from 12- to 15-year-olds.