AZD1222 effectiveness against severe COVID-19 in individuals with comorbidity or frailty: The RAVEN cohort study.

Objectives: Despite being prioritized during initial COVID-19 vaccine rollout, vulnerable individuals at high risk of severe COVID-19 (hospitalization, intensive care unit admission, or death) remain underrepresented in vaccine effectiveness (VE) studies. The RAVEN cohort study (NCT05047822) assessed AZD1222 (ChAdOx1 nCov-19) two-dose primary series VE in vulnerable populations.
Methods: Using the Oxford-Royal College of General Practitioners Clinical Informatics Digital Hub, linked to secondary care, death registration, and COVID-19 datasets in England, COVID-19 outcomes in 2021 were compared in vaccinated and unvaccinated individuals matched on age, sex, region, and multimorbidity.
Results: Over 4.5 million AZD1222 recipients were matched (mean follow-up ∼5 months); 68% were ≥50 years, 57% had high multimorbidity. Overall, high VE against severe COVID-19 was demonstrated, with lower VE observed in vulnerable populations. VE against hospitalization was higher in the lowest multimorbidity quartile (91.1%; 95% CI: 90.1, 92.0) than the highest quartile (80.4%; 79.7, 81.1), and among individuals ≥65 years, higher in the 'fit' (86.2%; 84.5, 87.6) than the frailest (71.8%; 69.3, 74.2). VE against hospitalization was lowest in immunosuppressed individuals (64.6%; 60.7, 68.1).
Conclusions: Based on integrated and comprehensive UK health data, overall population-level VE with AZD1222 was high. VEs were notably lower in vulnerable groups, particularly the immunosuppressed.
Competing Interests: Declaration of Competing Interest Oxford University has entered into a partnership with AstraZeneca for the development of COVID-19 vaccines. KS, LC, MO, ST, SV, TM, TNT, and WM are employees of AstraZeneca and may own stock/shares. AJP was a member of the World Health Organization’s Strategic Advisory Group of Experts on Immunization until January 2022 and remains Chair of the UK Department of Health and Social Care's Joint Committee on Vaccination and Immunisation (JCVI) but does not participate in the JCVI COVID-19 committee. AJP also reports providing advice to Shionogi on COVID-19, and funding from the National Institute for Health Research (NIHR), AstraZeneca, the Bill & Melinda Gates Foundation, Wellcome, the Medical Research Council, the Serum Institute of India, and the Coalition for Epidemic Preparedness Innovations (CEPI); and being a contributor to the intellectual property licensed by Oxford University Innovation to AstraZeneca. DAC reports consulting fees from Oxford University Consulting, Bristol Myers Squibb, and grants from UK Research and Innovation, Wellcome Trust, NIHR, Hong Kong ITC, AstraZeneca, and Glaxo Smith Kline (GSK); and patents held by Oxford University Innovation. JD is an employee at Momentum data and may own stocks/shares. FDRH acknowledges support as Director of the NIHR Applied Research Collaboration Oxford Thames Valley and Theme Lead of the NIHR Oxford University Hospitals Biomedical Research Centre. He also reports fees or expenses for speaking or consultancy from AstraZeneca, Boehringer Ingelheim, Bayer, Bristol Myers Squibb/Pfizer, and Novartis. GJ reports ownership of GSK stocks/shares and honoraria form AstraZeneca. SdeL reports advisory board membership for AstraZeneca, GSK, Sanofi, and Seqirus (fees paid to University); and receiving university research grants from AstraZeneca, GSK, Sanofi, Seqirus, and Takeda. ST reports ownership of GSK stocks/shares. UH is an employee at Oxford University and reports membership on a Janssen advisory committee, funding from Seqirus for podcasts, and research funding from Seqirus and AstraZeneca. WH resorts partial salary funding from AstraZeneca-sponsored research grants. AD, AF, DK, KST, MF, MJ, RB, RW, SNA, and XF declare no competing interests.
(Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)