Real-world effectiveness of BNT162b2 against infection and severe diseases in children and adolescents

Wu, Q; Tong, J; Zhang, B; et al., Annals of Internal Medicine, February 2024

View Publication on PubMed

February 2024
Annals of Internal Medicine

Short Summary

This RECOVER study looks at how well and how long a COVID-19 vaccine, BNT162b2, works in children and teens. Researchers studied this before and during the wave of a new type of COVID-19, called Omicron. Researchers looked at the electronic health records from a group of children’s health systems across the country, known as PEDSnet. They checked 3 groups: teens ages 12–20 during the earlier Delta wave; and both children ages 5–11 and teens ages 12-20 during the Omicron wave. Researchers looked at data from more than 77,000 teenagers during Delta and over 167,000 kids and teens during Omicron. Some of these kids were vaccinated, and some were not. Researchers compared those who got the first dose of the BNT162b2 vaccine to those who didn't get any COVID-19 vaccine. During Delta, researchers found that the vaccine stopped almost all the teenagers (98%) from getting sick. In the Omicron wave, the vaccine helped stop 74% of the kids and 86% of the teenagers from getting COVID-19. It also helped keep kids from getting really sick and needing to go to the hospital. Children and teens who got vaccinated were also less likely to have heart problems during Omicron. But they found that the vaccines didn’t work as well 4 months after the first dose. This information helps doctors better understand how to keep kids healthy when COVID-19 is going around.

This summary was prepared by the RECOVER Initiative.

Publication Details

DOI: 10.7326/M23-1754

Abstract

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.

Authors

Qiong Wu, Jiayi Tong, Bingyu Zhang, Dazheng Zhang, Jiajie Chen, Yuqing Lei, Yiwen Lu, Yudong Wang, Lu Li, Yishan Shen, Jie Xu, L Charles Bailey, Jiang Bian, Dimitri A Christakis, Megan L Fitzgerald, Kathryn Hirabayashi, Ravi Jhaveri, Alka Khaitan, Tianchen Lyu, Suchitra Rao, Hanieh Razzaghi, Hayden T Schwenk, Fei Wang, Margot I Gage Witvliet, Eric J Tchetgen Tchetgen, Jeffrey S Morris, Christopher B Forrest, Yong Chen

Keywords

United States; Humans; Adolescent; Child; BNT162 Vaccine; COVID-19 Vaccines; COVID-19/prevention & control; Comparative Effectiveness Research; Hospitalization