Risk of severe outcomes among Omicron sub-lineages BA.4.6, BA.2.75 and BQ.1 compared to BA.5 in England

Since the emergence of Omicron variant of SARS-CoV-2 in late 2021, a number of sub-lineages have arisen and circulated internationally. Little is known about the relative severity of Omicron sub-lineages BA.2.75, BA.4.6 and BQ.1. We undertook a case-control analysis to determine the clinical severity of these lineages relative to BA.5, using whole genome sequenced, PCR-confirmed infections, between 1 August 2022 to 27 November 2022, among those who presented to emergency care in England 14 days after and up to one day prior to the positive specimen. A total of 10,375 episodes were included in the analysis, of which 5,207 (50.2%) were admitted to hospital or died. Multivariable conditional regression analyses found no evidence for greater odds of hospital admission or death among those with BA.2.75 (OR= 0.96, 95% CI: 0.84 to 1.09), and BA.4.6 (OR= 1.02, 95% CI: 0.88 to 1.17) or BQ.1 (OR= 1.03, 95 % CI: 0.94 to 1.13) compared to BA.5. Future lineages may not follow the same trend and there remains a need for continued surveillance of COVID-19 variants and their clinical outcomes to inform the public health response.