The Sarbecoviruses encodes a large panel of highly heterogeneous, but related zoonotic, epidemic and pandemic coronaviruses that include SARS-CoV and SARS-CoV2, which have been associated with significant human disease in 2003 and 2020-21, respectively. These viruses exist in zoonotic reservoirs and many are poised to move easily between species. SARS-CoV2 has caused over hundreds of millions of cases and over 6 million deaths, globally. The presentation will discuss SARS-CoV2 host range, cross species transmission strategies, viral genetics, replication, evolution, pathogenic mechanisms and immunity, framed in the context of the development of novel countermeasures to control COVID19 disease severity in human populations.