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BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age

BACKGROUND: Limited evidence is available on the real-world effectiveness of the BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) and specifically against infection with the omicron variant among children 5 to 11 years of age. METHODS: Using data from the largest health care organization...

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Autores principales: Cohen-Stavi, Chandra J., Magen, Ori, Barda, Noam, Yaron, Shlomit, Peretz, Alon, Netzer, Doron, Giaquinto, Carlo, Judd, Ali, Leibovici, Leonard, Hernán, Miguel A., Lipsitch, Marc, Reis, Ben Y., Balicer, Ran D., Dagan, Noa
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Massachusetts Medical Society 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9258754/
https://www.ncbi.nlm.nih.gov/pubmed/35767475
http://dx.doi.org/10.1056/NEJMoa2205011
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author Cohen-Stavi, Chandra J.
Magen, Ori
Barda, Noam
Yaron, Shlomit
Peretz, Alon
Netzer, Doron
Giaquinto, Carlo
Judd, Ali
Leibovici, Leonard
Hernán, Miguel A.
Lipsitch, Marc
Reis, Ben Y.
Balicer, Ran D.
Dagan, Noa
author_facet Cohen-Stavi, Chandra J.
Magen, Ori
Barda, Noam
Yaron, Shlomit
Peretz, Alon
Netzer, Doron
Giaquinto, Carlo
Judd, Ali
Leibovici, Leonard
Hernán, Miguel A.
Lipsitch, Marc
Reis, Ben Y.
Balicer, Ran D.
Dagan, Noa
author_sort Cohen-Stavi, Chandra J.
collection PubMed
description BACKGROUND: Limited evidence is available on the real-world effectiveness of the BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) and specifically against infection with the omicron variant among children 5 to 11 years of age. METHODS: Using data from the largest health care organization in Israel, we identified a cohort of children 5 to 11 years of age who were vaccinated on or after November 23, 2021, and matched them with unvaccinated controls to estimate the vaccine effectiveness of BNT162b2 among newly vaccinated children during the omicron wave. Vaccine effectiveness against documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and symptomatic Covid-19 was estimated after the first and second vaccine doses. The cumulative incidence of each outcome in the two study groups through January 7, 2022, was estimated with the use of the Kaplan–Meier estimator, and vaccine effectiveness was calculated as 1 minus the risk ratio. Vaccine effectiveness was also estimated in age subgroups. RESULTS: Among 136,127 eligible children who had been vaccinated during the study period, 94,728 were matched with unvaccinated controls. The estimated vaccine effectiveness against documented infection was 17% (95% confidence interval [CI], 7 to 25) at 14 to 27 days after the first dose and 51% (95% CI, 39 to 61) at 7 to 21 days after the second dose. The absolute risk difference between the study groups at days 7 to 21 after the second dose was 1905 events per 100,000 persons (95% CI, 1294 to 2440) for documented infection and 599 events per 100,000 persons (95% CI, 296 to 897) for symptomatic Covid-19. The estimated vaccine effectiveness against symptomatic Covid-19 was 18% (95% CI, −2 to 34) at 14 to 27 days after the first dose and 48% (95% CI, 29 to 63) at 7 to 21 days after the second dose. We observed a trend toward higher vaccine effectiveness in the youngest age group (5 or 6 years of age) than in the oldest age group (10 or 11 years of age). CONCLUSIONS: Our findings suggest that as omicron was becoming the dominant variant, two doses of the BNT162b2 messenger RNA vaccine provided moderate protection against documented SARS-CoV-2 infection and symptomatic Covid-19 in children 5 to 11 years of age. (Funded by the European Union through the VERDI project and others.)
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spelling pubmed-92587542022-07-08 BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age Cohen-Stavi, Chandra J. Magen, Ori Barda, Noam Yaron, Shlomit Peretz, Alon Netzer, Doron Giaquinto, Carlo Judd, Ali Leibovici, Leonard Hernán, Miguel A. Lipsitch, Marc Reis, Ben Y. Balicer, Ran D. Dagan, Noa N Engl J Med Original Article BACKGROUND: Limited evidence is available on the real-world effectiveness of the BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) and specifically against infection with the omicron variant among children 5 to 11 years of age. METHODS: Using data from the largest health care organization in Israel, we identified a cohort of children 5 to 11 years of age who were vaccinated on or after November 23, 2021, and matched them with unvaccinated controls to estimate the vaccine effectiveness of BNT162b2 among newly vaccinated children during the omicron wave. Vaccine effectiveness against documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and symptomatic Covid-19 was estimated after the first and second vaccine doses. The cumulative incidence of each outcome in the two study groups through January 7, 2022, was estimated with the use of the Kaplan–Meier estimator, and vaccine effectiveness was calculated as 1 minus the risk ratio. Vaccine effectiveness was also estimated in age subgroups. RESULTS: Among 136,127 eligible children who had been vaccinated during the study period, 94,728 were matched with unvaccinated controls. The estimated vaccine effectiveness against documented infection was 17% (95% confidence interval [CI], 7 to 25) at 14 to 27 days after the first dose and 51% (95% CI, 39 to 61) at 7 to 21 days after the second dose. The absolute risk difference between the study groups at days 7 to 21 after the second dose was 1905 events per 100,000 persons (95% CI, 1294 to 2440) for documented infection and 599 events per 100,000 persons (95% CI, 296 to 897) for symptomatic Covid-19. The estimated vaccine effectiveness against symptomatic Covid-19 was 18% (95% CI, −2 to 34) at 14 to 27 days after the first dose and 48% (95% CI, 29 to 63) at 7 to 21 days after the second dose. We observed a trend toward higher vaccine effectiveness in the youngest age group (5 or 6 years of age) than in the oldest age group (10 or 11 years of age). CONCLUSIONS: Our findings suggest that as omicron was becoming the dominant variant, two doses of the BNT162b2 messenger RNA vaccine provided moderate protection against documented SARS-CoV-2 infection and symptomatic Covid-19 in children 5 to 11 years of age. (Funded by the European Union through the VERDI project and others.) Massachusetts Medical Society 2022-06-29 /pmc/articles/PMC9258754/ /pubmed/35767475 http://dx.doi.org/10.1056/NEJMoa2205011 Text en Copyright © 2022 Massachusetts Medical Society. All rights reserved. http://www.nejmgroup.org/legal/terms-of-use.htm This article is made available via the PMC Open Access Subset for unrestricted re-use, except commercial resale, and analyses in any form or by any means with acknowledgment of the original source. PMC is granted a license to make this article available via PMC and Europe PMC, subject to existing copyright protections.
spellingShingle Original Article
Cohen-Stavi, Chandra J.
Magen, Ori
Barda, Noam
Yaron, Shlomit
Peretz, Alon
Netzer, Doron
Giaquinto, Carlo
Judd, Ali
Leibovici, Leonard
Hernán, Miguel A.
Lipsitch, Marc
Reis, Ben Y.
Balicer, Ran D.
Dagan, Noa
BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age
title BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age
title_full BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age
title_fullStr BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age
title_full_unstemmed BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age
title_short BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age
title_sort bnt162b2 vaccine effectiveness against omicron in children 5 to 11 years of age
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9258754/
https://www.ncbi.nlm.nih.gov/pubmed/35767475
http://dx.doi.org/10.1056/NEJMoa2205011
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