Risk factors for SARS-CoV-2 infection after primary vaccination with ChAdOx1 nCoV-19 or BNT162b2 and after booster vaccination with BNT162b2 or mRNA-1273: A population-based cohort study (COVIDENCE UK)

Giulia Vivaldi; David A Jolliffe; Hayley Holt; Florence Tydeman; Mohammad Talaei; Gwyneth A Davies; Ronan A Lyons; Christopher J Griffiths; Frank Kee; Aziz Sheikh; Seif O Shaheen; Adrian R Martineau

doi:10.1016/j.lanepe.2022.100501

Risk factors for SARS-CoV-2 infection after primary vaccination with ChAdOx1 nCoV-19 or BNT162b2 and after booster vaccination with BNT162b2 or mRNA-1273: A population-based cohort study (COVIDENCE UK)

Lancet Reg Health Eur. 2022 Sep 23:22:100501. doi: 10.1016/j.lanepe.2022.100501. eCollection 2022 Nov.

Authors

Giulia Vivaldi^{1

2}, David A Jolliffe^{1

2}, Hayley Holt^{1

2

3}, Florence Tydeman^{1

2}, Mohammad Talaei², Gwyneth A Davies⁴, Ronan A Lyons⁴, Christopher J Griffiths^{2

3}, Frank Kee⁵, Aziz Sheikh⁶, Seif O Shaheen², Adrian R Martineau^{1

2

3}

Affiliations

¹ Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
² Wolfson Institute of Population Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
³ Asthma UK Centre for Applied Research, Queen Mary University of London, London, UK.
⁴ Population Data Science, Swansea University Medical School, Singleton Park, Swansea, UK.
⁵ Centre for Public Health Research (NI), Queen's University Belfast, Belfast, UK.
⁶ Usher Institute, University of Edinburgh, Edinburgh, UK.

Abstract

Background: Little is known about how demographic, behavioural, and vaccine-related factors affect risk of post-vaccination SARS-CoV-2 infection. We aimed to identify risk factors for SARS-CoV-2 infection after primary and booster vaccinations.

Methods: This prospective, population-based, UK study in adults (≥16 years) vaccinated against SARS-CoV-2 assessed risk of breakthrough SARS-CoV-2 infection up to February, 2022, for participants who completed a primary vaccination course (ChAdOx1 nCoV-19 or BNT162b2) and those who received a booster dose (BNT162b2 or mRNA-1273). Cox regression models explored associations between sociodemographic, behavioural, clinical, pharmacological, and nutritional factors and test-positive breakthrough infection, adjusted for local weekly SARS-CoV-2 incidence.

Findings: 1051 (7·1%) of 14 713 post-primary participants and 1009 (9·5%) of 10 665 post-booster participants reported breakthrough infection, over a median follow-up of 203 days (IQR 195-216) and 85 days (66-103), respectively. Primary vaccination with ChAdOx1 (vs BNT162b2) was associated with higher risk of infection in both post-primary analysis (adjusted hazard ratio 1·63, 95% CI 1·41-1·88) and after an mRNA-1273 booster (1·26 [1·00-1·57] vs BNT162b2 primary and booster). Lower risk of infection was associated with older age (post-primary: 0·97 [0·96-0·97] per year; post-booster: 0·97 [0·97-0·98]), whereas higher risk of infection was associated with lower educational attainment (post-primary: 1·78 [1·44-2·20] for primary/secondary vs postgraduate; post-booster: 1·46 [1·16-1·83]) and at least three weekly visits to indoor public places (post-primary: 1·36 [1·13-1·63] vs none; post-booster: 1·29 [1·07-1·56]).

Interpretation: Vaccine type, socioeconomic status, age, and behaviours affect risk of breakthrough infection after primary and booster vaccinations.

Funding: Barts Charity, UK Research and Innovation Industrial Strategy Challenge Fund.

Keywords: BNT162b2; Breakthrough infection; ChAdOx1; SARS-CoV-2; Vaccination; mRNA-1273.