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

• Published in: Nature communications Vol. 13; no. 1; p. 6053
• Main Authors: Webster, H H, Nyberg, T, Sinnathamby, M A, Aziz, N Abdul, Ferguson, N, Seghezzo, G, Blomquist, P B, Bridgen, J, Chand, M, Groves, N, Myers, R, Hope, R, Ashano, E, Lopez-Bernal, J, De Angelis, D, Dabrera, G, Presanis, A M, Thelwall, S
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 13.10.2022; Nature Portfolio
• Subjects: Cohort analysis; Cohort Studies; COVID-19; COVID-19 - epidemiology; Death; Electronic health records; Electronic medical records; Gene sequencing; Genomes; Hospitalization; Humans; Infections; Mortality; Mortality risk; Public health; Regression analysis; Regression models; Risk; SARS-CoV-2 - genetics; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Whole genome sequencing; United Kingdom > UK; England
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-33740-9

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.