The trivalent influenza vaccine contains all of the following strains except:
(A) H IN I (B) H3N2 (C) H2N 1 (D) Influenza B
(C) Ans: C. H2N 1Each seasonal influenza vaccine contains antigens representing three (trivalent vaccine) or four (quadrivalent vaccine) influenza virus strains: one influenza type A subtype H1 N1 virus strain, one influenza type A subtype H3N2 virus strain, and either one or two influenza type B virus strains.