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| Yong Chen, PhD | Eric Tchetgen Tchetgen, PhD |
Congratulations to CCEB Senior Scholars and Penn/CHOP colleagues Yong Chen, Jeffrey Morris, Eric Tchetgen Tchetgen, Christopher Forrest and colleagues on their important publication in Ann Intern Med on COVID vaccination effectiveness and durability in children and adolescents. Pulling these types of large real world studies together is critical for understanding interventions and their impacts on public health. Many of these investigators are pursuing similar efforts within the Penn Center for Health Analytics and Synthesis of Evidence (CHASE).
Background:
The efficacy of the BNT162b2 vaccine in pediatrics was assessed by randomized trials before the Omicron variant’s emergence. The long-term durability of vaccine protection in this population during the Omicron period remains limited.
Objective:
To assess the effectiveness of BNT162b2 in preventing infection and severe diseases with various strains of the SARS-CoV-2 virus in previously uninfected children and adolescents.
Design:
Comparative effectiveness research accounting for underreported vaccination in 3 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.
Setting:
A national collaboration of pediatric health systems (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 the BNT162b2 vaccine versus no receipt of COVID-19 vaccine.
Measurements:
Outcomes of interest include documented infection, COVID-19 illness severity, admission to an intensive care unit (ICU), and cardiac complications. The effectiveness was reported as (1-relative risk)*100, with confounders balanced via propensity score stratification.
Results:
During the Delta period, the estimated effectiveness of the BNT162b2 vaccine was 98.4% (95% CI, 98.1% to 98.7%) against documented infection among adolescents, with no statistically significant waning after receipt of the first dose. An analysis of cardiac complications did not suggest a statistically significant difference between vaccinated and unvaccinated groups. During the Omicron period, the effectiveness against documented infection among children was estimated to be 74.3% (CI, 72.2% to 76.2%). Higher levels of effectiveness were seen against moderate or 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%]). Among adolescents, the effectiveness against documented Omicron infection was 85.5% (CI, 83.8% to 87.1%), with 84.8% (CI, 77.3% to 89.9%) against moderate or severe COVID-19, and 91.5% (CI, 69.5% to 97.6%) against ICU admission with COVID-19. The effectiveness of the BNT162b2 vaccine against the Omicron variant declined 4 months after the first dose and then stabilized. The analysis showed a lower risk for cardiac complications in the vaccinated group during the Omicron variant period.
Limitation:
Observational study design and potentially undocumented infection.
Conclusion:
This study suggests that BNT162b2 was effective for various COVID-19–related outcomes in children and adolescents during the Delta and Omicron periods, and there is some evidence of waning effectiveness over time.
Primary Funding Source:
National Institutes of Health.
Annals of Internal Medicine