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Kerr S, Bedston S, Bradley DT, Joy M, Lowthian E, Mulholland RM, Akbari A, Hobbs FDR, Katikireddi SV, de Lusignan S, Rudan I, Torabi F, Tsang RSM, Lyons RA, Robertson C, Sheikh A. Waning of first- and second-dose ChAdOx1 and BNT162b2 COVID-19 vaccinations: a pooled target trial study of 12.9 million individuals in England, Northern Ireland, Scotland and Wales. Int J Epidemiol 2023; 52:22-31. [PMID: 36272418 PMCID: PMC9620314 DOI: 10.1093/ije/dyac199] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 09/30/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Several SARS-CoV-2 vaccines have been shown to provide protection against COVID-19 hospitalization and death. However, some evidence suggests that notable waning in effectiveness against these outcomes occurs within months of vaccination. We undertook a pooled analysis across the four nations of the UK to investigate waning in vaccine effectiveness (VE) and relative vaccine effectiveness (rVE) against severe COVID-19 outcomes. METHODS We carried out a target trial design for first/second doses of ChAdOx1(Oxford-AstraZeneca) and BNT162b2 (Pfizer-BioNTech) with a composite outcome of COVID-19 hospitalization or death over the period 8 December 2020 to 30 June 2021. Exposure groups were matched by age, local authority area and propensity for vaccination. We pooled event counts across the four UK nations. RESULTS For Doses 1 and 2 of ChAdOx1 and Dose 1 of BNT162b2, VE/rVE reached zero by approximately Days 60-80 and then went negative. By Day 70, VE/rVE was -25% (95% CI: -80 to 14) and 10% (95% CI: -32 to 39) for Doses 1 and 2 of ChAdOx1, respectively, and 42% (95% CI: 9 to 64) and 53% (95% CI: 26 to 70) for Doses 1 and 2 of BNT162b2, respectively. rVE for Dose 2 of BNT162b2 remained above zero throughout and reached 46% (95% CI: 13 to 67) after 98 days of follow-up. CONCLUSIONS We found strong evidence of waning in VE/rVE for Doses 1 and 2 of ChAdOx1, as well as Dose 1 of BNT162b2. This evidence may be used to inform policies on timings of additional doses of vaccine.
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Affiliation(s)
- Steven Kerr
- Centre for Medical Informatics, Usher Institute, The University of Edinburgh, Edinburgh, UK
| | - Stuart Bedston
- Population Data Science, Swansea University Medical School, Swansea University, Swansea, UK
| | - Declan T Bradley
- School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, UK
- Public Health Agency, Belfast, UK
| | - Mark Joy
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - Emily Lowthian
- Population Data Science, Swansea University Medical School, Swansea University, Swansea, UK
- Department of Education and Childhood Studies, Swansea University, Swansea, UK
| | - Rachel M Mulholland
- Centre for Medical Informatics, Usher Institute, The University of Edinburgh, Edinburgh, UK
| | - Ashley Akbari
- Population Data Science, Swansea University Medical School, Swansea University, Swansea, UK
| | - F D Richard Hobbs
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | | | - Simon de Lusignan
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - Igor Rudan
- Centre for Medical Informatics, Usher Institute, The University of Edinburgh, Edinburgh, UK
| | - Fatemeh Torabi
- Population Data Science, Swansea University Medical School, Swansea University, Swansea, UK
| | - Ruby S M Tsang
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - Ronan A Lyons
- Population Data Science, Swansea University Medical School, Swansea University, Swansea, UK
| | - Chris Robertson
- Public Health Scotland, Glasgow, UK
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK
| | - Aziz Sheikh
- Centre for Medical Informatics, Usher Institute, The University of Edinburgh, Edinburgh, UK
- BREATHE—The Health Data Research Hub for Respiratory Health, The University of Edinburgh, Edinburgh, UK
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