Nucleocapsid mutations R203K/G204R increase the infectivity, fitness and virulence of SARS-CoV-2

 SARS-CoV-2 variants of concern or interest including B.1.1.7 and P.1 contain mutations R203K/G204R in viral nucleocapsid, and viruses possessing this mutation are spreading worldwide. These mutations were shown to be involved in the more efficient viral growth in human lung cells and hamsters. The disease severity was found to be correlated with the frequency of this mutation by using clinical dataset. The mutation may play a role for the increased efficiency of viral ribonucleoprotein complex formation that will lead to the enhanced replication capacity.