There are three types of seasonal influenza – A, B and C. Type A influenza viruses are further typed into subtypes according to different kinds and combinations of virus surface proteins.

有三种类型的季节性流感——甲型、乙型和丙型。 根据病毒表面蛋白不同的种类和结合情况，甲型流感病毒又进一步分类为亚型。

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This year’s seasonal vaccine contains three influenza viruses — one A (H3N2) virus, one regular seasonal A (H1N1) virus unrelated to the swine flu strain and one B virus.

今年的季节流感疫苗含有三种流感病毒——一种甲型（H3N2）病毒，一种与猪流感毒株无关的常规季节性甲型（H1N1）病毒，以及一种乙型病毒。

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Influenza a, B and c, three separate strains of the virus, cause the flu.

三种不同的流感病毒流感A型、流感B型和流感C型都能引起流感。

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This year's North American vaccine is made from three viruses: two types of influenza A virus (H3N2 and H1N1) and an influenza B virus.

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