COVID-19 is a pneumonic disease that is caused by SARS-Cov2 virus. Previous ancestors of COVID-19 virus are SARS-CoV and MERS Virus. Loss of few base pairs has led to the mutation in the genetic material of SARS-CoV2. High multiplication rate in the host is one of the remarkable properties of this virus. Incubation period for SARS-Cov2 virus is 3-4 days, which is very less as compared to the incubation period of other viruses. This is one of the major cause of its virulence.