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

2024; Elsevier BV; Volume: 88; Issue: 4 Linguagem: Inglês

10.1016/j.jinf.2024.106129

1532-2742

Wilhelmine Meeraus, Mark Joy, Mario Ouwens, Kathryn Taylor, Sudhir Venkatesan, John Dennis, Trung N. Tran, Ashkan Dashtban, Xuejuan Fan, Robert Williams, Tamsin Morris, Lucy Carty, Debasish Kar, Uy Hoang, Michael Feher, Anna Forbes, Gavin Jamie, William Hinton, Kornelia Sanecka, Rachel Byford, Sneha Anand, Richard Hobbs, David A. Clifton, Andrew J. Pollard, Sylvia Taylor, Simon de Lusignan,

COVID-19 Clinical Research Studies

Highlights•AZD1222 (ChAdOx1 nCoV-19) real-world vaccine effectiveness (VE) in 2021 was studied.•Over 4.5 million vaccinated individuals were assessed with ∼5 months mean follow-up.•VE was 84.1%/90.7%/85.9% for hospitalization/intensive care admission/death.•People with higher comorbidity burden or more severe frailty had lower VE.•Immunosuppressed individuals had the lowest VE from primary series vaccination.SummaryObjectivesDespite 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.MethodsUsing 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.ResultsOver 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).ConclusionsBased 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.Graphical abstract