Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved]
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) vacc...
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Wellcome
2023-11-01
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| Series: | Wellcome Open Research |
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| Online Access: | https://wellcomeopenresearch.org/articles/8-96/v2 |
| _version_ | 1797471949785399296 |
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| author | Elizabeth Miller Nick Andrews Jada Hackman Stefan Flasche Pauline Waight Charlotte M. Gower Stephane Hué Catriona Skarnes Freja CM Kirsebom Jamie Lopez Bernal Samuel Clifford Louise Letley |
| author_facet | Elizabeth Miller Nick Andrews Jada Hackman Stefan Flasche Pauline Waight Charlotte M. Gower Stephane Hué Catriona Skarnes Freja CM Kirsebom Jamie Lopez Bernal Samuel Clifford Louise Letley |
| author_sort | Elizabeth Miller |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-03-09T19:55:21Z |
| format | Article |
| id | doaj.art-b46c7714afde4025a1772fd7768985a5 |
| institution | Directory Open Access Journal |
| issn | 2398-502X |
| language | English |
| last_indexed | 2024-03-09T19:55:21Z |
| publishDate | 2023-11-01 |
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| series | Wellcome Open Research |
| spelling | doaj.art-b46c7714afde4025a1772fd7768985a52023-11-24T01:00:00ZengWellcomeWellcome Open Research2398-502X2023-11-01822475Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved]Elizabeth Miller0Nick Andrews1Jada Hackman2https://orcid.org/0000-0001-8412-8674Stefan Flasche3https://orcid.org/0000-0002-5808-2606Pauline Waight4Charlotte M. Gower5Stephane Hué6Catriona Skarnes7Freja CM Kirsebom8Jamie Lopez Bernal9Samuel Clifford10https://orcid.org/0000-0002-3774-3882Louise Letley11Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UKNational Infection Service, UK Health Security Agency, London, NW9 5EQ, UKCentre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UKCentre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UKNational Infection Service, UK Health Security Agency, London, NW9 5EQ, UKNational Infection Service, UK Health Security Agency, London, NW9 5EQ, UKCentre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UKNational Infection Service, UK Health Security Agency, London, NW9 5EQ, UKNational Infection Service, UK Health Security Agency, London, NW9 5EQ, UKNational Infection Service, UK Health Security Agency, London, NW9 5EQ, UKCentre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UKNational Infection Service, UK Health Security Agency, London, NW9 5EQ, UKBackground 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.https://wellcomeopenresearch.org/articles/8-96/v2covid vaccination secondary attack rate SARS-CoV-2 household transmissioneng |
| spellingShingle | Elizabeth Miller Nick Andrews Jada Hackman Stefan Flasche Pauline Waight Charlotte M. Gower Stephane Hué Catriona Skarnes Freja CM Kirsebom Jamie Lopez Bernal Samuel Clifford Louise Letley Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved] Wellcome Open Research covid vaccination secondary attack rate SARS-CoV-2 household transmission eng |
| title | Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved] |
| title_full | Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved] |
| title_fullStr | Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved] |
| title_full_unstemmed | Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved] |
| title_short | Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England [version 2; peer review: 2 approved] |
| title_sort | effectiveness of bnt162b2 and chadox1 against sars cov 2 household transmission a prospective cohort study in england version 2 peer review 2 approved |
| topic | covid vaccination secondary attack rate SARS-CoV-2 household transmission eng |
| url | https://wellcomeopenresearch.org/articles/8-96/v2 |
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