RacCS203 is a bat-derived strain of severe acute respiratory syndrome–related coronavirus collected in acuminate horseshoe bats from sites in Thailand and sequenced by Lin-Fa Wang's team. It has 91.5% sequence similarity to SARS-CoV-2 and is most related to the RmYN02 strain. Its spike protein is closely related to RmYN02's spike, both highly divergent from SARS-CoV-2's spike.

A phylogenetic tree based on whole-genome sequences of SARS-CoV-2 and related coronaviruses is: