Hospitalisation and mortality risk of SARS-COV-2 variant omicron sub-lineage BA.2 compared to BA.1 in England

H. H. Webster, T. Nyberg, M. A. Sinnathamby, N. Abdul Aziz, N. Ferguson, G. Seghezzo, P. B. Blomquist, J. Bridgen, M. Chand, N. Groves, R. Myers, R. Hope, E. Ashano, J. Lopez-Bernal, D. De Angelis, G. Dabrera, A. M. Presanis, S. Thelwall*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The Omicron variant of SARS-CoV-2 became the globally dominant variant in early 2022. A sub-lineage of the Omicron variant (BA.2) was identified in England in January 2022. Here, we investigated hospitalisation and mortality risks of COVID-19 cases with the Omicron sub-lineage BA.2 (n = 258,875) compared to BA.1 (n = 984,337) in a large cohort study in England. We estimated the risk of hospital attendance, hospital admission or death using multivariable stratified proportional hazards regression models. After adjustment for confounders, BA.2 cases had lower or similar risks of death (HR = 0.80, 95% CI 0.71–0.90), hospital admission (HR = 0.88, 95% CI 0.83–0.94) and any hospital attendance (HR = 0.98, 95% CI 0.95–1.01). These findings that the risk of severe outcomes following infection with BA.2 SARS-CoV-2 was slightly lower or equivalent to the BA.1 sub-lineage can inform public health strategies in countries where BA.2 is spreading.

Original languageEnglish
Article number6053
JournalNature Communications
Volume13
Issue number1
DOIs
Publication statusPublished - Dec 2022

Bibliographical note

Funding Information:
We would like to acknowledge the efforts of multiple teams in enabling the severity assessment of this SARS-CoV-2 variant. We would like to thank the UKHSA Second Generation Surveillance System, DataLake and Datastore teams for maintaining the databases in which the data are stored. We thank NHS Digital and Hospital-onset COVID team at UKHSA for enabling surveillance of hospitalisation. We also thank colleagues for maintaining COVID-19 vaccination surveillance at the National Immunisation Management service, Julia Stowe and Freya Kirsebom (UKHSA, Immunisation and Vaccine Preventable Diseases Division) and colleagues for helpful discussions surrounding hospitalisation surveillance, and Andre Charlett (UKHSA Statistics, Modelling and Economics division) for his ongoing work overseeing the UKHSA COVID-19 data streams. This work was supported by UK Research and Innovation (UKRI) Medical Research Council (MRC) (NMF: Centre for Global Infectious Disease Analysis [MR/R015600/1]; DDA, AMP: [Unit Programme number MC/UU/00002/11]); UKRI MRC/Department of Health and Social Care (DHSC) National Institute for Health and Care Research (NIHR) COVID-19 rapid response call (TN, DDA, AMP: [MC/PC/19074]; NMF: [MR/V038109/1]); NIHR Health Protection Units in: Modelling and Health Economics (NMF), and Behavioural Science and Evaluation (DDA); philanthropic funding from Community Jameel (NMF); and the WHO Regional Office for Europe (TN, DDA, AMP). The funders played no direct role in the study. The views expressed are those of the authors and not necessarily those of the NIHR or the DHSC.

Funding Information:
T.N., N.M.F., D.D.A., G.D., A.M.P., and S.T. conceived and designed the study. P.B.B., J.B., E.A., G.S., R.H., and J.L.B. lead the collection of and advised on the use and implementation of the data on S-gene target, hospitalisation, COVID-19 mortality and vaccination. M.C. led the genomic sequencing surveillance for UKHSA and the creation of this data resource. N.G. and R.M. developed case definitions by which variant status is assigned. T.N. designed the statistical analysis, with support from N.M.F., D.D.A. and A.M.P. H.H.W. linked the datasets and performed the statistical analysis, supported by T.N. and N.A.A. H.H.W. and M.A.S. drafted the first version of the manuscript. T.N. and S.T. contributed to a revised draft. All authors read, revised and approved the final version of the manuscript.

Funding Information:
We would like to acknowledge the efforts of multiple teams in enabling the severity assessment of this SARS-CoV-2 variant. We would like to thank the UKHSA Second Generation Surveillance System, DataLake and Datastore teams for maintaining the databases in which the data are stored. We thank NHS Digital and Hospital-onset COVID team at UKHSA for enabling surveillance of hospitalisation. We also thank colleagues for maintaining COVID-19 vaccination surveillance at the National Immunisation Management service, Julia Stowe and Freya Kirsebom (UKHSA, Immunisation and Vaccine Preventable Diseases Division) and colleagues for helpful discussions surrounding hospitalisation surveillance, and Andre Charlett (UKHSA Statistics, Modelling and Economics division) for his ongoing work overseeing the UKHSA COVID-19 data streams. This work was supported by UK Research and Innovation (UKRI) Medical Research Council (MRC) (NMF: Centre for Global Infectious Disease Analysis [MR/R015600/1]; DDA, AMP: [Unit Programme number MC/UU/00002/11]); UKRI MRC/Department of Health and Social Care (DHSC) National Institute for Health and Care Research (NIHR) COVID-19 rapid response call (TN, DDA, AMP: [MC/PC/19074]; NMF: [MR/V038109/1]); NIHR Health Protection Units in: Modelling and Health Economics (NMF), and Behavioural Science and Evaluation (DDA); philanthropic funding from Community Jameel (NMF); and the WHO Regional Office for Europe (TN, DDA, AMP). The funders played no direct role in the study. The views expressed are those of the authors and not necessarily those of the NIHR or the DHSC.

Publisher Copyright:
© 2022, Crown.

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