Influenza is an Orthomyxovirus composed of 8 single-stranded negative-sense RNA segments which encode 11 proteins, one of which is an error-prone polymerase that is conducive to gradual genetic mutations and subsequent drift in the major influenza antigenic determinants: hemagglutinin (HA) and neuraminidase (NA) (1–4). The gene discussed is XK; the disease is influenza.