XK and influenza: During the epidemic turnover of dominant variants from clade 2B-1 to 2B-2 viruses within the two influenza seasons of 2007–2008 and 2008–2009 in Taiwan, several major substitutions were detected without genomic reassortment, including A206T in HA, H275Y and D354G in NA, N642S in PB1, L30R and H41P in PB1-F2 and V411I and P453S in PB2 (Table 3).