TUESDAY, Nov. 14, 2023 (HealthDay News) — Protection against severe acute respiratory syndrome coronavirus 2 (SAR-CoV-2) infection is highest for middle and high school students with hybrid immunity from previous infection and recent COVID-19 vaccination with a third dose, according to a study published online Nov. 14 in Pediatrics.
Olivia M. Almendares, M.S.P.H., from the COVID-19 Response Team at the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues used data from 17,910 Utah middle and high school students participating in schoolwide antigen testing in January 2022 to estimate the protection of previous SARS-CoV-2 infection and COVID-19 vaccination against SARS-CoV-2 infection.
The researchers found that 16.7 percent of the students had documented previous SARS-CoV-2 infection; 55.6 percent had received two vaccine doses and 8.6 percent of those aged 16 to 19 years had received three doses, with 211 and 21 median days since the second and third doses, respectively. For students aged 12 to 15 and 16 to 19 years, protection from previous infection alone was 35.9 and 23.8 percent, respectively. For two-dose hybrid immunity (previous SARS-CoV-2 infection plus vaccination) with <180 days since the second dose, protection was 58.7 and 54.7 percent for students age 12 to 15 and 16 to 19 years, respectively. The highest protection was seen for students with three-dose hybrid immunity (70.0 percent), although the confidence intervals overlapped with two-dose vaccination.
“These real-world, programmatic data from school-based testing were useful to reveal the relative effectiveness of past infection and/or vaccination in preventing infections in child and adolescent populations,” the authors write.
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