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

BACKGROUND: Since it was first identified in early November 2021, the B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread quickly and replaced the B.1.617.2 (delta) variant as the dominant variant in many countries. Data on the real-world effectiven...

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Autores principales: Tan, Sharon H.X., Cook, Alex R., Heng, Derrick, Ong, Benjamin, Lye, David C., Tan, Kelvin B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Massachusetts Medical Society 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9342421/
https://www.ncbi.nlm.nih.gov/pubmed/35857701
http://dx.doi.org/10.1056/NEJMoa2203209
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author Tan, Sharon H.X.
Cook, Alex R.
Heng, Derrick
Ong, Benjamin
Lye, David C.
Tan, Kelvin B.
author_facet Tan, Sharon H.X.
Cook, Alex R.
Heng, Derrick
Ong, Benjamin
Lye, David C.
Tan, Kelvin B.
author_sort Tan, Sharon H.X.
collection PubMed
description BACKGROUND: Since it was first identified in early November 2021, the B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread quickly and replaced the B.1.617.2 (delta) variant as the dominant variant in many countries. Data on the real-world effectiveness of vaccines against the omicron variant in children are lacking. METHODS: In a study conducted from January 21, 2022, through April 8, 2022, when the omicron variant was spreading rapidly, we analyzed data on children in Singapore who were 5 to 11 years of age. We assessed the incidences of all reported SARS-CoV-2 infections (confirmed on polymerase-chain-reaction [PCR] assay, rapid antigen testing, or both), SARS-CoV-2 infections confirmed on PCR assay, and coronavirus disease 2019 (Covid-19)–related hospitalizations among unvaccinated, partially vaccinated (≥1 day after the first dose of vaccine and up to 6 days after the second dose), and fully vaccinated children (≥7 days after the second dose). Poisson regression was used to estimate vaccine effectiveness from the incidence rate ratio of outcomes. RESULTS: A total of 255,936 children were included in the analysis. Among unvaccinated children, the crude incidence rates of all reported SARS-CoV-2 infections, PCR-confirmed SARS-CoV-2 infections, and Covid-19–related hospitalizations were 3303.5, 473.8, and 30.0 per 1 million person-days, respectively. Among partially vaccinated children, vaccine effectiveness was 13.6% (95% confidence interval [CI], 11.7 to 15.5) against all SARS-CoV-2 infections, 24.3% (95% CI, 19.5 to 28.9) against PCR-confirmed SARS-CoV-2 infection, and 42.3% (95% CI, 24.9 to 55.7) against Covid-19–related hospitalization; in fully vaccinated children, vaccine effectiveness was 36.8% (95% CI, 35.3 to 38.2), 65.3% (95% CI, 62.0 to 68.3), and 82.7% (95% CI, 74.8 to 88.2), respectively. CONCLUSIONS: During a period when the omicron variant was predominant, BNT162b2 vaccination reduced the risks of SARS-CoV-2 infection and Covid-19–related hospitalization among children 5 to 11 years of age.
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spelling pubmed-93424212022-08-01 Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age Tan, Sharon H.X. Cook, Alex R. Heng, Derrick Ong, Benjamin Lye, David C. Tan, Kelvin B. N Engl J Med Original Article BACKGROUND: Since it was first identified in early November 2021, the B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread quickly and replaced the B.1.617.2 (delta) variant as the dominant variant in many countries. Data on the real-world effectiveness of vaccines against the omicron variant in children are lacking. METHODS: In a study conducted from January 21, 2022, through April 8, 2022, when the omicron variant was spreading rapidly, we analyzed data on children in Singapore who were 5 to 11 years of age. We assessed the incidences of all reported SARS-CoV-2 infections (confirmed on polymerase-chain-reaction [PCR] assay, rapid antigen testing, or both), SARS-CoV-2 infections confirmed on PCR assay, and coronavirus disease 2019 (Covid-19)–related hospitalizations among unvaccinated, partially vaccinated (≥1 day after the first dose of vaccine and up to 6 days after the second dose), and fully vaccinated children (≥7 days after the second dose). Poisson regression was used to estimate vaccine effectiveness from the incidence rate ratio of outcomes. RESULTS: A total of 255,936 children were included in the analysis. Among unvaccinated children, the crude incidence rates of all reported SARS-CoV-2 infections, PCR-confirmed SARS-CoV-2 infections, and Covid-19–related hospitalizations were 3303.5, 473.8, and 30.0 per 1 million person-days, respectively. Among partially vaccinated children, vaccine effectiveness was 13.6% (95% confidence interval [CI], 11.7 to 15.5) against all SARS-CoV-2 infections, 24.3% (95% CI, 19.5 to 28.9) against PCR-confirmed SARS-CoV-2 infection, and 42.3% (95% CI, 24.9 to 55.7) against Covid-19–related hospitalization; in fully vaccinated children, vaccine effectiveness was 36.8% (95% CI, 35.3 to 38.2), 65.3% (95% CI, 62.0 to 68.3), and 82.7% (95% CI, 74.8 to 88.2), respectively. CONCLUSIONS: During a period when the omicron variant was predominant, BNT162b2 vaccination reduced the risks of SARS-CoV-2 infection and Covid-19–related hospitalization among children 5 to 11 years of age. Massachusetts Medical Society 2022-07-20 /pmc/articles/PMC9342421/ /pubmed/35857701 http://dx.doi.org/10.1056/NEJMoa2203209 Text en Copyright © 2022 Massachusetts Medical Society. All rights reserved. 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
Tan, Sharon H.X.
Cook, Alex R.
Heng, Derrick
Ong, Benjamin
Lye, David C.
Tan, Kelvin B.
Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age
title Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age
title_full Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age
title_fullStr Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age
title_full_unstemmed Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age
title_short Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age
title_sort effectiveness of bnt162b2 vaccine against omicron in children 5 to 11 years of age
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9342421/
https://www.ncbi.nlm.nih.gov/pubmed/35857701
http://dx.doi.org/10.1056/NEJMoa2203209
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