Estimated effectiveness did not wane during delta period but did decline against the omicron variant after the first dose
By Elana Gotkine HealthDay Reporter
MONDAY, Jan. 8, 2024 (HealthDay News) — In children and adolescents, BNT162b2 was effective for COVID-19-related outcomes during the delta and omicron periods, according to a study published online Jan. 9 in the Annals of Internal Medicine.
Qiong Wu, Ph.D., from the University of Pennsylvania Perelman School of Medicine in Philadelphia, and colleagues examined the effectiveness of BNT162b2 with different strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in previously uninfected children. Effectiveness was examined among 77,392 adolescents (45,007 vaccinated) during the delta phase and 111,539 children (50,398 vaccinated) and 56,080 adolescents (21,180 vaccinated) during the omicron phase.
The researchers found that the estimated effectiveness of the BNT162b2 vaccine was 98.4 percent against documented infection among adolescents during the delta period, with no significant waning observed after receipt of the first dose. No significant difference was seen in cardiac complications between vaccinated and unvaccinated groups. The effectiveness against documented infection during the omicron period was estimated to be 74.3 percent among children, with higher effectiveness observed against moderate or severe COVID-19 (75.5 percent) and intensive care unit admission with COVID-19 (84.9 percent). Among adolescents, the corresponding effectiveness was 85.5, 84.8, and 91.5 percent. There was a decline noted in the effectiveness of the BNT162b2 vaccine against the omicron variant four months after the first dose, which then stabilized. During the omicron period, the risk for cardiac complications was lower in the vaccinated group.
“Our assessment of vaccine effectiveness across diverse outcomes underscores the vaccine’s pivotal role in reducing SARS-CoV-2 transmission, minimizing COVID-19-related sick leaves, and alleviating economic burdens during the pandemic,” the authors write.
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