At seven to 21 days after second dose, estimated effectiveness was 90 percent against infection, 93 percent against symptomatic COVID-19
FRIDAY, Oct. 22, 2021 (HealthDay News) — The BNT162b2 vaccine is highly effective against the delta variant among adolescents aged 12 to 18 years, according to a letter to the editor published online Oct. 20 in the New England Journal of Medicine.
Ben Y. Reis, Ph.D., from Boston Children’s Hospital, and colleagues estimated the vaccine effectiveness of BNT162b2 against the delta variant among vaccinated adolescents. Data were obtained from the largest health care organization in Israel to conduct an observational cohort study involving adolescents aged 12 to 18 years without a previous record of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and who had been vaccinated between June 8 and Sept. 14, 2021. During this period, the delta variant was responsible for more than 95 percent of new infections in Israel. A total of 94,354 vaccine recipients were matched to 94,354 unvaccinated controls. The frequency of testing for SARS-CoV-2 was similar for vaccinated and unvaccinated adolescents (9.4 and 9.9 tests, respectively, per 100 persons/week).
The researchers found that at days 14 through 20 after the first dose, 21 to 27 after the first dose, and seven to 21 after the second dose, the estimated vaccine effectiveness against documented SARS-CoV-2 infection was 59, 66, and 90 percent, respectively. The corresponding estimated vaccine effectiveness against symptomatic COVID-19 was 57, 82, and 93 percent.
“Our results show that the BNT162b2 mRNA vaccine was highly effective in the first few weeks after vaccination against both documented infection and symptomatic COVID-19 with the delta variant among adolescents between the ages of 12 and 18 years,” the authors write.
Several authors disclosed financial ties to biopharmaceutical companies, including Pfizer.
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