Ward, Isobel L;
Bermingham, Charlotte;
Ayoubkhani, Daniel;
Gethings, Owen J;
Pouwels, Koen B;
Yates, Tomas;
Khunti, Kamlesh;
... Nafilyan, Vahe; + view all
(2022)
Risk of COVID-19 related deaths for SARS-CoV-2 Omicron (B.1.1.529) compared with Delta (B.1.617.2).
BMJ: British Medical Journal
(In press).
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Abstract
OBJECTIVE: To assess the risk of COVID-19 death following infection from Omicron BA.1 relative to Delta (B.1.617.2). DESIGN: Retrospective cohort study. SETTING: England, UK, 1 December 2021 to 30 December 2021. PARTICIPANTS: 1,035,149 people aged 18-100 years who tested positive for SARS-CoV-2 in the national surveillance programme, and had an infection identified as either Omicron BA.1- or Delta compatible. MAIN OUTCOME MEASURES: COVID-19 death as identified from death certification records. The exposure of interest was the SARS-CoV-2 variant identified from NHS Test and Trace PCR positive tests taken in the community (pillar 2) and analysed by Lighthouse laboratories. Cause-specific Cox proportional hazard regression models (censoring non-COVID-19 deaths) were adjusted for sex, age, vaccination status, previous infection, calendar time, ethnicity, Index of Multiple Deprivation rank, household deprivation, university degree, keyworker status, country of birth, main language, region, disability, and comorbidities. Additionally, we tested for interactions between variant and sex, age, vaccination status and comorbidities. RESULTS: The risk of COVID-19 death was 66% lower (95% CI: 54% to 75%) for Omicron BA.1 compared to Delta. The reduction in the risk of death involving COVID-19 for Omicron compared to Delta was more pronounced in 18-59-year-olds (HR=0.14, 95%CI: 0.07 to 0.27) compared to individuals over 70 years of age (HR=0.44, 95%CI: 0.32 to 0.61) (p < 0.0001). We find no evidence of a difference in risk between variant and number of comorbidities (0, 1-2, 3+). CONCLUSIONS: Our results support early work showing the relative reduction in severity of Omicron BA.1 compared to Delta in terms of hospitalisation and extends this research to assess COVID-19 mortality.
| Type: | Article |
|---|---|
| Title: | Risk of COVID-19 related deaths for SARS-CoV-2 Omicron (B.1.1.529) compared with Delta (B.1.617.2) |
| Open access status: | An open access version is available from UCL Discovery |
| Publisher version: | https://www.bmj.com/ |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Inst of Clinical Trials and Methodology > MRC Clinical Trials Unit at UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Inst of Clinical Trials and Methodology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10151222 |
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