SARS-CoV-2 variants and considerations of inferring causality on disease severity

Abstract

The SARS-CoV-2 B.1.1.7 variant that was first identified in Kent (UK) in December, 2020, has now spread to many countries and shown consistent fitness advantage over other variants in circulation at the time.1 This means an increase in transmission potential, which alone can lead to increased rates of hospitalisations and deaths. In The Lancet Infectious Diseases, Peter Bager and colleagues report the risk of hospitalisation with B.1.1.7 variant using the impressive population-level sequencing data in Denmark that include cases detected from both community-based and hospital-based testing.