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Pfizer Vaccine Efficacy in Teens Wanes 27 Days After Dose 2, Study Shows

Pfizer Vaccine Efficacy in Teens Wanes 27 Days After Dose 2, Study Shows | 11 Aug 2022 | The effectiveness of Pfizer's-BioNTech COVID-19 vaccine against symptomatic COVID-19 infection among adolescents "rapidly declined over time," waning from just 27 days after the second dose, according to the 23 authors of a new study that analyzed data from more than 600,000 teens in Brazil and Scotland. The study, published Aug. 8 in The Lancet Infectious Diseases, analyzed nationwide data from 503,776 COVID-19 tests of 2,948,538 adolescents... COVID-19 vaccine rollout for adolescents began in August 2021 in Scotland and September 2021 in Brazil, said the University of Minnesota's Center for Infectious Disease Research and Policy. The study showed vaccine efficacy began to decline 27 days after the second dose for both countries, plummeting to 5.9% (95% CI 2.2–9.4) in Brazil and dropping to 50.6% (95% CI 42.7–57.4) in Scotland at 98 days after adolescents received the second dose.