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Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England

BACKGROUND: The ability of SARS-CoV-2 vaccines to protect against infection and onward transmission determines whether immunisation can control global circulation. We estimated the effectiveness of Pfizer-BioNTech mRNA vaccine (BNT162b2) and Oxford AstraZeneca adenovirus vector vaccine (ChAdOx1) vac...

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Autores principales: Clifford, Samuel, Waight, Pauline, Hackman, Jada, Hué, Stephane, Gower, Charlotte M., Kirsebom, Freja CM, Skarnes, Catriona, Letley, Louise, Lopez Bernal, Jamie, Andrews, Nick, Flasche, Stefan, Miller, Elizabeth
Formato: Online Artículo Texto
Lenguaje:English
Publicado: F1000 Research Limited 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10697107/
http://dx.doi.org/10.12688/wellcomeopenres.17995.2
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author Clifford, Samuel
Waight, Pauline
Hackman, Jada
Hué, Stephane
Gower, Charlotte M.
Kirsebom, Freja CM
Skarnes, Catriona
Letley, Louise
Lopez Bernal, Jamie
Andrews, Nick
Flasche, Stefan
Miller, Elizabeth
author_facet Clifford, Samuel
Waight, Pauline
Hackman, Jada
Hué, Stephane
Gower, Charlotte M.
Kirsebom, Freja CM
Skarnes, Catriona
Letley, Louise
Lopez Bernal, Jamie
Andrews, Nick
Flasche, Stefan
Miller, Elizabeth
author_sort Clifford, Samuel
collection PubMed
description BACKGROUND: The ability of SARS-CoV-2 vaccines to protect against infection and onward transmission determines whether immunisation can control global circulation. We estimated the effectiveness of Pfizer-BioNTech mRNA vaccine (BNT162b2) and Oxford AstraZeneca adenovirus vector vaccine (ChAdOx1) vaccines against acquisition and transmission of the Alpha and Delta variants in a prospective household study in England. METHODS: Households were recruited based on adult purported index cases testing positive after reverse transcription-quantitative (RT-q)PCR testing of oral-nasal swabs. Purported index cases and their household contacts took oral-nasal swabs on days 1, 3 and 7 after enrolment and a subset of the PCR-positive swabs underwent genomic sequencing conducted on a subset. We used Bayesian logistic regression to infer vaccine effectiveness against acquisition and transmission, adjusted for age, vaccination history and variant. RESULTS: Between 2 February 2021 and 10 September 2021, 213 index cases and 312 contacts were followed up. After excluding households lacking genomic proximity (N=2) or with unlikely serial intervals (N=16), 195 households with 278 contacts remained, of whom 113 (41%) became PCR positive. Delta lineages had 1.53 times the risk (95% Credible Interval: 1.04 – 2.20) of transmission than Alpha; contacts older than 18 years old were 1.48 (1.20 – 1.91) and 1.02 (0.93 – 1.16) times more likely to acquire an Alpha or Delta infection than children. Effectiveness of two doses of BNT162b2 against transmission of Delta was 36% (-1%, 66%) and 49% (18%, 73%) for ChAdOx1, similar to their effectiveness for Alpha. Protection against infection with Alpha was higher than for Delta, 69% (9%, 95%) vs. 18% (-11%, 59%), respectively, for BNT162b2 and 24% (-41%, 72%) vs. 9% (-15%, 42%), respectively, for ChAdOx1. CONCLUSIONS: BNT162b2 and ChAdOx1 reduce transmission of the Delta variant from breakthrough infections in the household setting, although their protection against infection within this setting is low.
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spelling pubmed-106971072023-12-06 Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England Clifford, Samuel Waight, Pauline Hackman, Jada Hué, Stephane Gower, Charlotte M. Kirsebom, Freja CM Skarnes, Catriona Letley, Louise Lopez Bernal, Jamie Andrews, Nick Flasche, Stefan Miller, Elizabeth Wellcome Open Res Research Article BACKGROUND: The ability of SARS-CoV-2 vaccines to protect against infection and onward transmission determines whether immunisation can control global circulation. We estimated the effectiveness of Pfizer-BioNTech mRNA vaccine (BNT162b2) and Oxford AstraZeneca adenovirus vector vaccine (ChAdOx1) vaccines against acquisition and transmission of the Alpha and Delta variants in a prospective household study in England. METHODS: Households were recruited based on adult purported index cases testing positive after reverse transcription-quantitative (RT-q)PCR testing of oral-nasal swabs. Purported index cases and their household contacts took oral-nasal swabs on days 1, 3 and 7 after enrolment and a subset of the PCR-positive swabs underwent genomic sequencing conducted on a subset. We used Bayesian logistic regression to infer vaccine effectiveness against acquisition and transmission, adjusted for age, vaccination history and variant. RESULTS: Between 2 February 2021 and 10 September 2021, 213 index cases and 312 contacts were followed up. After excluding households lacking genomic proximity (N=2) or with unlikely serial intervals (N=16), 195 households with 278 contacts remained, of whom 113 (41%) became PCR positive. Delta lineages had 1.53 times the risk (95% Credible Interval: 1.04 – 2.20) of transmission than Alpha; contacts older than 18 years old were 1.48 (1.20 – 1.91) and 1.02 (0.93 – 1.16) times more likely to acquire an Alpha or Delta infection than children. Effectiveness of two doses of BNT162b2 against transmission of Delta was 36% (-1%, 66%) and 49% (18%, 73%) for ChAdOx1, similar to their effectiveness for Alpha. Protection against infection with Alpha was higher than for Delta, 69% (9%, 95%) vs. 18% (-11%, 59%), respectively, for BNT162b2 and 24% (-41%, 72%) vs. 9% (-15%, 42%), respectively, for ChAdOx1. CONCLUSIONS: BNT162b2 and ChAdOx1 reduce transmission of the Delta variant from breakthrough infections in the household setting, although their protection against infection within this setting is low. F1000 Research Limited 2023-11-02 /pmc/articles/PMC10697107/ http://dx.doi.org/10.12688/wellcomeopenres.17995.2 Text en Copyright: © 2023 Clifford S et al. https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Clifford, Samuel
Waight, Pauline
Hackman, Jada
Hué, Stephane
Gower, Charlotte M.
Kirsebom, Freja CM
Skarnes, Catriona
Letley, Louise
Lopez Bernal, Jamie
Andrews, Nick
Flasche, Stefan
Miller, Elizabeth
Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England
title Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England
title_full Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England
title_fullStr Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England
title_full_unstemmed Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England
title_short Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England
title_sort effectiveness of bnt162b2 and chadox1 against sars-cov-2 household transmission: a prospective cohort study in england
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10697107/
http://dx.doi.org/10.12688/wellcomeopenres.17995.2
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