Study explains how the B.1.1.7 SARS-CoV-2 variant is more transmissible The B.1.1.7 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant was initially found in England last fall and has quickly overtaken to become the dominant coronavirus strain in the United Kingdom (UK). The variant’s ability to increase transmission and severe infections has proven to be a challenge for public health officials looking to limit the spread. New research led by Thushan I. de Silva from the University of Sheffield proposes that increases in subgenomic RNA (sgRNA) expression cause increased viral transmissibility and subsequent infection. They suggest the ORF9 protein, found in high amounts of sgRNA, could be regulating interferon responses.