Effectiveness of Pfizer-BioNTech mRNA Vaccination Against COVID-19 Hospitalization Among Persons Aged 12-18 Years - United States, June-September 2021

MMWR Morb Mortal Wkly Rep. 2021 Oct 22;70(42):1483-1488. doi: 10.15585/mmwr.mm7042e1.


Pfizer-BioNTech COVID-19 vaccine is authorized for use in children and adolescents aged 12-15 years and is licensed by the Food and Drug Administration (FDA) for persons aged ≥16 (1). A randomized placebo-controlled trial demonstrated an efficacy of 100% (95% confidence interval [CI] = 75.3%-100%) in preventing outpatient COVID-19 in persons aged 12-15 years (2); however, data among adolescents on vaccine effectiveness (VE) against COVID-19 in real-world settings are limited, especially among hospitalized patients. In early September 2021, U.S. pediatric COVID-19 hospitalizations reached the highest level during the pandemic (3,4). In a test-negative, case-control study at 19 pediatric hospitals in 16 states during June 1-September 30, 2021, the effectiveness of 2 doses of Pfizer-BioNTech vaccine against COVID-19 hospitalization was assessed among children and adolescents aged 12-18 years. Among 464 hospitalized persons aged 12-18 years (179 case-patients and 285 controls), the median age was 15 years, 72% had at least one underlying condition, including obesity, and 68% attended in-person school. Effectiveness of 2 doses of Pfizer-BioNTech vaccine against COVID-19 hospitalization was 93% (95% CI = 83%-97%), during the period when B.1.617.2 (Delta) was the predominant variant. This evaluation demonstrated that 2 doses of Pfizer-BioNTech vaccine are highly effective at preventing COVID-19 hospitalization among persons aged 12-18 years and reinforces the importance of vaccination to protect U.S. youths against severe COVID-19.

MeSH terms

  • Adolescent
  • COVID-19 / epidemiology
  • COVID-19 / prevention & control*
  • COVID-19 Vaccines / administration & dosage*
  • Child
  • Female
  • Hospitalization / statistics & numerical data*
  • Humans
  • Male
  • United States / epidemiology
  • Vaccines, Synthetic


  • COVID-19 Vaccines
  • Vaccines, Synthetic
  • mRNA Vaccine