The real effectiveness of the BNT162b2 (Pfizer-BioNTech) vaccine against COVID-19 – Medical news
Real-world effectiveness of the BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine against severe infections and diseases in children and adolescents
Background:
The effectiveness of the BNT162b2 vaccine in pediatrics was assessed in randomized trials even before the introduction of the Omicron variant. The long-term sustainability of vaccine protection in this population during the Omicron period remains limited.
Target:
To evaluate the effectiveness of BNT162b2 in preventing severe infection and disease with different strains of the SARS-CoV-2 virus in previously uninfected children and adolescents.
Design:
Comparative effectiveness study considering unannounced vaccination in three study cohorts: adolescents (12 to 20 years) during the Delta phase and children (5 to 11 years) and adolescents (12 to 20 years) during the Omicron phase. .
Parameter:
National Pediatric Health Systems Collaborative (PEDSnet).
Participants:
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.
Intervention:
First dose of BNT162b2 vaccine versus no COVID-19 vaccine.
Dimensions:
Outcomes of interest included documented infection, COVID-19 disease severity, intensive care unit (ICU) admission, and cardiac complications. Efficacy was estimated as (1-relative risk)*100, with confounders balanced by propensity score stratification.
Results:
During the Delta period, the estimated efficacy of BNT162b2 vaccine was 98.4% (95% CI: 98.1–98.7%) against documented infection among adolescents, with no statistically significant decline after the first dose.
Analysis of cardiac complications did not reveal a statistically significant difference between the vaccinated and unvaccinated groups.
During the period of use of Omicron, the effectiveness against documented infections among children was estimated at 74.3% (CI 72.2% to 76.2%). Higher efficacy rates were observed for moderate to severe COVID-19 (75.5% (CI 69.0% to 81.0%)) and ICU admission with COVID-19 (84.9% (CI 64.8% to 93.5%)).