Gregory J. Walker

The paper shows how SARS-CoV-2 variants, particularly Omicron, evolved proteolytic controls at the Spike furin cleavage site to enhance transmission while reducing lower respiratory tract pathogenicity.

This study tracks SARS-CoV-2 evolution through 33-100 serial passages in vitro, identifying convergent mutations that may confer fitness or transmissibility advantages.

The paper shows Omicron SARS-CoV-2 lineages rely on ACE2 without TMPRSS2 complexes for entry, due to changes in the ACE2 Collectrin-Like Domain affecting TMPRSS2 activation.

The paper identifies a SARS-CoV-2 variant with an ORF7a deletion that persisted during a major outbreak but shows no clear fitness advantage in cell culture.