Cause of antigenic drift in influenza viral infections is
antigenic drift - small changes in the genes of influenza viruses that happen continually over time as the virus replicates.Antigenic shift - an abrupt, major change in the influenza A viruses, resulting in new hemagglutinin and neuraminidase proteins in influenza viruses that infect humans.
Small mutation in neuraminidase and hemagglutinin
Large mutations in hemagglutinin only
Step mutations in viral genome
None of the above
All India exam