Hospitalization and Mortality Risk for COVID-19 Cases With SARS-CoV-2 AY.4.2 (VUI-21OCT-01) Compared to Non-AY.4.2 Delta Variant Sublineages.

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To investigate if the AY.4.2 sublineage of the SARS-CoV-2 delta variant is associated with hospitalization and mortality risks that differ from non-AY.4.2 delta risks, we performed a retrospective cohort study of sequencing-confirmed COVID-19 cases in England based on linkage of routine health care datasets. Using stratified Cox regression, we estimated adjusted hazard ratios (aHR) of hospital admission (aHR = 0.85; 95% confidence interval [CI], .77-.94), hospital admission or emergency care attendance (aHR = 0.87; 95% CI, .81-.94), and COVID-19 mortality (aHR = 0.85; 95% CI, .71-1.03). The results indicate that the risks of hospitalization and mortality are similar or lower for AY.4.2 compared to cases with other delta sublineages.


Funder: NIHR Health Protection Unit in Behavioural Science and Evaluation

AY.4.2, COVID-19, SARS-CoV-2, VUI-21OCT-01, hospitalization, mortality, COVID-19, Hospitalization, Humans, Retrospective Studies, SARS-CoV-2
Journal Title
J Infect Dis
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Oxford University Press (OUP)
MRC (unknown)
MRC (MC_PC 19074)
National Institute for Health Research (NIHR) (via University of Bristol) (200877 2020 - 245)
National Institute for Health and Care Research (IS-BRC-1215-20014)
UKRI Medical Research Council (MC_UU_00002/11; MC_UU_00002/10); MRC UKRI/DHSC NIHR COVID-19 rapid response call (MC_PC_19074); NIHR Health Protection Unit in Behavioural Science and Evaluation; NIHR Cambridge Biomedical Research Centre (BRC-1215-20014)