Victoria-lineage strains compared with B/Hongkong/330/2001 had six mutation points in antigenic determinants within amplified region,Yamagata-lineage strains compared with B/Beijing/76/98 had three mutation points,and with B/Sichuan/379/99 had ten.

• Victoria系易变区抗原表位有6个位点氨基酸不同于B/Hongkong/330/2001,Yamagata系易变区抗原表位有3个位点氨基酸不同于B/Beijing/76/98,有10个位点不同于B/Sichuan/379/99。