Top 5 Takeaways

1. Vaccine Effectiveness (VE) in Children: Two doses of the Pfizer-BioNTech vaccine provided 46% effectiveness against COVID-19–associated emergency department (ED) and urgent care (UC) encounters among children aged 5–11 years.
2. VE in Adolescents: For adolescents aged 12–15 and 16–17 years, VE was 83% and 76% respectively within 14–149 days after the second dose, but dropped significantly after 150 days.
3. Impact of Omicron Variant: VE was lower during Omicron predominance, with no significant protection observed 150 days after the second dose among adolescents aged 12–17 years. However, a booster dose restored VE to 81% among adolescents aged 16–17 years.
4. Hospitalization Protection: VE against COVID-19–associated hospitalization was 74% for children aged 5–11 years and ranged from 73% to 94% for adolescents aged 12–17 years, depending on the time since vaccination.
5. Public Health Recommendation: All eligible children and adolescents should stay up to date with recommended COVID-19 vaccinations, including a booster dose for those aged 12–17 years.

Original Article Author and Citation

Corresponding Author

Nicola P. Klein, Nicola.Klein@kp.org

Suggested Citation

Klein NP, Stockwell MS, Demarco M, et al. Effectiveness of COVID-19 Pfizer-BioNTech BNT162b2 mRNA Vaccination in Preventing COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Nonimmunocompromised Children and Adolescents Aged 5–17 Years — VISION Network, 10 States, April 2021–January 2022. MMWR Morb Mortal Wkly Rep 2022;71:352–358. DOI: http://dx.doi.org/10.15585/mmwr.mm7109e3

Summary

This study evaluated the effectiveness of the Pfizer-BioNTech BNT162b2 mRNA vaccine in preventing COVID-19–associated emergency department (ED) and urgent care (UC) encounters and hospitalizations among nonimmunocompromised children and adolescents aged 5–17 years across 10 states from April 2021 to January 2022. The findings indicate that two doses of the vaccine provided moderate protection against ED and UC encounters, with effectiveness varying by age group and time since vaccination. The study also highlighted a decrease in vaccine effectiveness during the Omicron variant predominance, particularly after 150 days post-vaccination, but noted that a booster dose restored effectiveness among older adolescents.

Methods

The study employed a case-control test-negative design to estimate vaccine effectiveness (VE). It included 39,217 ED and UC encounters and 1,699 hospitalizations among children and adolescents aged 5–17 years with COVID-19–like illness who had received SARS-CoV-2 molecular testing. VE was calculated by comparing the odds of a positive SARS-CoV-2 test result between vaccinated and unvaccinated patients using multivariable logistic regression models. The study periods were defined based on the availability of vaccines for each age group and the predominance of SARS-CoV-2 variants.

Discussion

The study found that the Pfizer-BioNTech vaccine provided substantial protection against COVID-19–associated ED and UC encounters and hospitalizations among children and adolescents. However, vaccine effectiveness decreased over time and was lower during the Omicron variant predominance. A booster dose significantly restored effectiveness among adolescents aged 16–17 years. These findings underscore the importance of staying up to date with COVID-19 vaccinations, including booster doses, to maintain high levels of protection.

Conclusion

The Pfizer-BioNTech BNT162b2 mRNA vaccine is effective in preventing COVID-19–associated ED and UC encounters and hospitalizations among children and adolescents aged 5–17 years. However, vaccine effectiveness decreases over time and during the Omicron variant predominance. A booster dose restores effectiveness among older adolescents, highlighting the need for timely booster vaccinations to sustain protection.

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