Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England
Background: We investigated whether COVID-19 vaccination reduced SARS-CoV-2 infection risk among adult household contacts of COVID-19 index cases during the Alpha, Delta, and Omicron waves in England. Methods: Between February 2021 and February 2022, SARS-CoV-2 RT-PCR nasal swabs were collected from...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-01-01
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| Series: | Vaccines |
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| Online Access: | https://www.mdpi.com/2076-393X/12/2/113 |
| _version_ | 1797296876933873664 |
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| author | Khitam Muhsen Pauline A. Waight Freja Kirsebom Nick Andrews Louise Letley Charlotte M. Gower Catriona Skarnes Catherine Quinot Rachel Lunt Jamie Lopez Bernal Stefan Flasche Elizabeth Miller |
| author_facet | Khitam Muhsen Pauline A. Waight Freja Kirsebom Nick Andrews Louise Letley Charlotte M. Gower Catriona Skarnes Catherine Quinot Rachel Lunt Jamie Lopez Bernal Stefan Flasche Elizabeth Miller |
| author_sort | Khitam Muhsen |
| collection | DOAJ |
| description | Background: We investigated whether COVID-19 vaccination reduced SARS-CoV-2 infection risk among adult household contacts of COVID-19 index cases during the Alpha, Delta, and Omicron waves in England. Methods: Between February 2021 and February 2022, SARS-CoV-2 RT-PCR nasal swabs were collected from COVID-19-confirmed index cases aged ≥20 years and their household contacts at enrolment and three and seven days thereafter. Generalized Estimating Equations models were fitted with SARS-CoV-2 positivity as the outcome and household contacts’ vaccination status as the main exposure while adjusting for confounders. Results: SARS-CoV-2 infection was confirmed in 238/472 household contacts (50.4%) aged ≥20 years. The adjusted relative risk (95% confidence interval) of infection in vaccinated versus unvaccinated household contacts was 0.50 (0.35–0.72) and 0.69 (0.53–0.90) for receipt of two doses 8–90 and >90 days ago, respectively, and 0.34 (0.23–0.50) for vaccination with three doses 8–151 days ago. Primary vaccination protected household contacts against infection during the Alpha and Delta waves, but only three doses protected during the Omicron wave. Vaccination with three doses in the index case independently reduced contacts’ infection risk: 0.45 (0.23–0.89). Conclusions: Vaccination of household contacts reduces their risk of infection under conditions of household exposure though, for Omicron, only after a booster dose. |
| first_indexed | 2024-03-07T22:11:09Z |
| format | Article |
| id | doaj.art-7f4ae2b9635b46ef9be99b718e4b4a1a |
| institution | Directory Open Access Journal |
| issn | 2076-393X |
| language | English |
| last_indexed | 2024-03-07T22:11:09Z |
| publishDate | 2024-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Vaccines |
| spelling | doaj.art-7f4ae2b9635b46ef9be99b718e4b4a1a2024-02-23T15:36:53ZengMDPI AGVaccines2076-393X2024-01-0112211310.3390/vaccines12020113Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in EnglandKhitam Muhsen0Pauline A. Waight1Freja Kirsebom2Nick Andrews3Louise Letley4Charlotte M. Gower5Catriona Skarnes6Catherine Quinot7Rachel Lunt8Jamie Lopez Bernal9Stefan Flasche10Elizabeth Miller11Department of Epidemiology and Preventive Medicine, School of Public Health, Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, IsraelUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKUK Health Security Agency, 61 Colindale Avenue, London NW9 5EU, UKLondon School of Hygiene and Tropical Medicine, London WC1E 7HT, UKLondon School of Hygiene and Tropical Medicine, London WC1E 7HT, UKBackground: We investigated whether COVID-19 vaccination reduced SARS-CoV-2 infection risk among adult household contacts of COVID-19 index cases during the Alpha, Delta, and Omicron waves in England. Methods: Between February 2021 and February 2022, SARS-CoV-2 RT-PCR nasal swabs were collected from COVID-19-confirmed index cases aged ≥20 years and their household contacts at enrolment and three and seven days thereafter. Generalized Estimating Equations models were fitted with SARS-CoV-2 positivity as the outcome and household contacts’ vaccination status as the main exposure while adjusting for confounders. Results: SARS-CoV-2 infection was confirmed in 238/472 household contacts (50.4%) aged ≥20 years. The adjusted relative risk (95% confidence interval) of infection in vaccinated versus unvaccinated household contacts was 0.50 (0.35–0.72) and 0.69 (0.53–0.90) for receipt of two doses 8–90 and >90 days ago, respectively, and 0.34 (0.23–0.50) for vaccination with three doses 8–151 days ago. Primary vaccination protected household contacts against infection during the Alpha and Delta waves, but only three doses protected during the Omicron wave. Vaccination with three doses in the index case independently reduced contacts’ infection risk: 0.45 (0.23–0.89). Conclusions: Vaccination of household contacts reduces their risk of infection under conditions of household exposure though, for Omicron, only after a booster dose.https://www.mdpi.com/2076-393X/12/2/113COVID-19 vaccinationhousehold transmissionalpha variantdelta variantomicron variant |
| spellingShingle | Khitam Muhsen Pauline A. Waight Freja Kirsebom Nick Andrews Louise Letley Charlotte M. Gower Catriona Skarnes Catherine Quinot Rachel Lunt Jamie Lopez Bernal Stefan Flasche Elizabeth Miller Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England Vaccines COVID-19 vaccination household transmission alpha variant delta variant omicron variant |
| title | Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England |
| title_full | Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England |
| title_fullStr | Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England |
| title_full_unstemmed | Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England |
| title_short | Association between COVID-19 Vaccination and SARS-CoV-2 Infection among Household Contacts of Infected Individuals: A Prospective Household Study in England |
| title_sort | association between covid 19 vaccination and sars cov 2 infection among household contacts of infected individuals a prospective household study in england |
| topic | COVID-19 vaccination household transmission alpha variant delta variant omicron variant |
| url | https://www.mdpi.com/2076-393X/12/2/113 |
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