On October 29, 2021, the Food and Drug Administration authorized the BNT162b2 vaccine (Pfizer–BioNTech) for emergency use in children 5 to 11 years of age, on the basis of an immunobridging study and a small efficacy study.1 Recent case–control studies have shown modest short-term effectiveness of the BNT162b2 vaccine in this age group during the early phase of the period when the B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was spreading (from mid-December 2021 to mid-February 2022).2-4
We conducted a large cohort study over a 6-month period when the omicron variant was dominant. Here, we report on the protection conferred by the BNT162b2 vaccine and by previous SARS-CoV-2 infection against infection and coronavirus disease 2019 (Covid-19)–related hospitalization and death in children 5 to 11 years of age.
The data sources and statistical methods for this study have been described previously,5 and new details are provided in the Supplementary Methods section in the Supplementary Appendix, available with the full text of this letter at NEJM.org. Among 887,193 children 5 to 11 years of age in the study, 193,346 SARS-CoV-2 infections occurred between March 11, 2020, and June 3, 2022; a total of 309 of the infected children were known to be hospitalized, and 7 were known to have died (Table S1 in the Supplementary Appendix). A total of 273,157 children had received at least one dose of the BNT162b2 vaccine between November 1, 2021, and June 3, 2022.