Abstract: This paper introduces the respective epidemiological characteristics and clinical manifestations of severe acute respiratory syndrome coronavirus 2 （SARS-CoV-2）， including the wild-type strain， Delta variant and Omicron variant. It clarifies the current transmissibility， pathogenicity and virulence changes of the SARS-CoV-2， as well as the change in the clinical manifestations of patients. On this basis， this paper proposes the reasons and significance of changing the name of "Coronavirus Disease 2019" to " Coronavirus Infectious Syndrome 2019".