  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.
