Evolving biothreat of variant SARS-CoV-2 - molecular properties, virulence and epidemiology.

SARS-CoV-2 are enveloped RNA viruses that belong to the family Coronaviridae of genus Beta coronavirus, responsible for the COVID-19 pandemic. The mutation rate is high among RNA viruses and in particular, coronavirus replication is error prone with an estimated mutation rate of 4x10-4 nucleotide substitutions per site per year. Variants of SARS-CoV-2 have been reported from various countries like United Kingdom, South Africa, Denmark, Brazil and India.