Virological characteristics of SARS-CoV-2-related coronaviruses dynamically circulating in Southeast Asia.

By sampling horseshoe bats-the reservoir hosts of SARS-CoV-2-related coronaviruses (SC2r-CoVs)-in Thailand, we present two clades of SC2r-CoVs co-circulating in the same bat population. Through a comprehensive set of experimental approaches, including cryo-electron microscopy (cryo-EM), pseudovirus and live virus assays, and hamster experiments, we characterize the virological properties of these new viruses. We show that one of the two clades discovered in this study is able to bind the human angiotensin converting enzyme 2 (ACE2) receptor; however, it exhibits reduced fusogenicity and replication in vitro and lower pathogenicity and transmissibility compared with SARS-CoV-2. Phylogeography and recombination analyses reveal a complex evolutionary history for these viruses characterized by extensive, recent geographic movement and recombination with co-circulating virus lineages. Our findings provide new insights into the diversity of SC2r-CoVs dynamically co-circulating in Southeast Asia as well as the virological characteristics of these viruses relative to SARS-CoV-2.