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December 14, 2022

Estimated BNT162b2 Vaccine Effectiveness Against Infection With Delta and Omicron Variants Among US Children 5 to 11 Years of Age

Farid L. Khan, MPH1Jennifer L. Nguyen, ScD1Tanya G. Singh, MPH2et alLaura A. Puzniak, PhD1Timothy L. Wiemken, PhD1Joshua P. Schrecker, PharmD3Michael S. Taitel, PhD2Joann M. Zamparo, MPH1Luis Jodar, PhD1John M. McLaughlin, PhD1

Author Affiliations Article Information

JAMA Netw Open. 2022;5(12):e2246915. doi:10.1001/jamanetworkopen.2022.46915

Key Points

Question  What is the estimated vaccine effectiveness (VE) and durability of BNT162b2 against infection with the Delta and Omicron variants of SARS-CoV-2 among 5- to 11-year-old children?

Findings  In this test-negative case-control study of 160 002 children who underwent polymerase chain reaction testing for SARS-CoV-2 at locations of a pharmacy chain during Delta- and Omicron-predominant periods, the overall VE of 2 doses of BNT162b2 was 85% against Delta and 20% against Omicron; protection from the 2-dose vaccine against Omicron waned after approximately 3 months and was similar across sublineages (BA.1, BA.2/BA.2.12.1, and BA.4/BA.5). Booster effectiveness was 55% against Omicron and 40% or more against BA.4/BA.5 at 3 or more months after receipt of the booster.

Meaning  This study suggests that 2 BNT162b2 doses provided limited protection against Omicron infection and that a booster dose restored and maintained protection for at least 3 months.


Importance  Data describing the vaccine effectiveness (VE) and durability of BNT162b2 among children 5 to 11 years of age are needed.

Objective  To estimate BNT162b2 VE against SARS-CoV-2 infection among children aged 5 to 11 years during Delta and Omicron variant–predominant periods and to further assess VE according to prior SARS-CoV-2 infection status and by sublineage during the Omicron variant–predominant period.

Design, Setting, and Participants  This test-negative case-control study was conducted from November 2 to December 9, 2021 (Delta variant), and from January 16 to September 30, 2022 (Omicron variant), among 160 002 children tested at a large national US retail pharmacy chain, for SARS-CoV-2 via polymerase chain reaction (PCR); 62 719 children were tested during the Delta period, and 97 283 were tested during the Omicron period.

Exposure  Vaccination with BNT162b2 before SARS-CoV-2 testing vs no vaccination.

Main Outcomes and Measures  The primary outcome was SARS-CoV-2 infection confirmed by PCR (regardless of the presence of symptoms), and the secondary outcome was confirmed symptomatic infection. Adjusted estimated VE was calculated from multilevel logistic regression models.

Results  A total of 39 117 children tested positive and 131 686 tested negative for SARS-CoV-2 (total, 170 803; 84 487 [49%] were boys; mean [SD] age was 9 [2] years; 74 236 [43%] were White non-Hispanic or non-Latino; and 37 318 [22%] were Hispanic or Latino). Final VE analyses included 160 002 children without SARS-CoV-2 infection less than 90 days prior. The VE of 2 doses of BNT162b2 against Delta was 85% (95% CI, 80%-89%; median follow-up, 1 month) compared with the Omicron period (20% [95% CI, 17%-23%]; median follow-up, 4 months). The adjusted VE of 2 doses against Omicron at less than 3 months was 39% (95% CI, 36%-42%), and at 3 months or more, it was −1% (95% CI, −6% to 3%). Protection against Omicron was higher among children with vs without infection 90 days or more prior but decreased in all children approximately 3 months after the second dose (58% [95% CI, 49%-66%] with infection vs 37% [95% CI, 34%-41%] without infection at <3 months; 27% [95% CI, 17%-35%] with infection vs −7% [95% CI, −12% to −1%] at ≥3 months without infection). The VE of 2 doses of BNT162b2 at less than 3 months by Omicron sublineage was 40% (95% CI, 36%-43%) for BA.1, 32% (95% CI, 21%-41%) for BA.2/BA.2.12.1, and 50% (95% CI, 37%-60%) for BA.4/BA.5. After 3 months or more, VE was nonsignificant for BA.2/BA.2.12.1 and BA.4/BA.5. The VE of a booster dose was 55% (95% CI, 50%-60%) against Omicron, with no evidence of waning at 3 months or more.

Conclusions and Relevance  This study suggests that, among children aged 5 to 11 years, 2 doses of BNT162b2 provided modest short-term protection against Omicron infection that was higher for those with prior infection; however, VE waned after approximately 3 months in all children. A booster dose restored protection against Omicron and was maintained for at least 3 months. These findings highlight the continued importance of booster vaccination regardless of history of prior COVID-19.


Estimated BNT162b2 Vaccine Effectiveness Against Infection With Delta and Omicron Variants Among US Children 5 to 11 Years of Age | Pediatrics | JAMA Network Open | JAMA Network

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