Increased risk of hospitalisation for COVID-19 patients infected with SARS-CoV-2 variant B.1.1.7

OBJECTIVE: To evaluate the association between coronavirus disease 2019 (COVID-19) diagnosis with SARS-CoV-2 variant B.1.1.7 (also known as Variant of Concern 202012/01) and the risk of hospitalisation compared to diagnosis with wildtype SARS-CoV-2 variants. DESIGN: Retrospective cohort, analysed using a matched nested case-control study design. SETTING: Community-based SARS-CoV-2 testing in England, individually linked with hospitalisation data from the Secondary Uses Service and the Emergency Care Data Set. PARTICIPANTS: 493,053 laboratory-confirmed COVID-19 patients, of whom 19,482 had been hospitalised, tested between 23 November 2020 and 4 January 2021 and analysed at a laboratory with an available TaqPath assay that enables assessment of S-gene target failure (SGTF). SGTF is a proxy test for the B.1.1.7 variant. Nested case-control analysis of 18,814 pairs of hospitalised/non-hospitalised patients, one-to-one matched on age, sex, ethnicity, deprivation, region of residence, and date of positive test (matches found for 96.6%). MAIN OUTCOME MEASURES: Hospitalisation between 1 and 14 days after the first positive SARS-CoV-2 test. RESULTS: The matching-adjusted conditional odds ratio of hospitalisation was 1.58 (95% confidence interval 1.50 to 1.67) for COVID-19 patients infected with a SGTF-associated variant, compared to those infected with non-SGTF-associated variants. Secondary cohort analyses yielded similar estimates. The effect was modified by age (p<0.001), with ORs of 0.96-1.13 below age 20 years and 1.57-1.67 in age groups 40 years or older. CONCLUSIONS: The results suggest that the risk of hospitalisation is higher for individuals infected with the B.1.1.7 variant compared to wildtype SARS-CoV-2, likely reflecting a more severe disease. The higher severity may be specific to older age groups.