['Avian H5N1 influenza A virus is an emerging pathogen with the potential to cause substantial human morbidity and mortality. We evaluated the ability of currently licensed seasonal influenza vaccine to confer cross-protection against highly pathogenic H5N1 influenza virus in mice.', 'BALB/c mice were inoculated 3 times, either intranasally or subcutaneously, with the trivalent inactivated influenza vaccine licensed in Japan for the 2005-2006 season. The vaccine included A/NewCaledonia/20/99 (H1N1), A/NewYork/55/2004 (H3N2), and B/Shanghai/361/2002 viral strains and was administered together with poly(I):poly(C(12)U) (Ampligen) as an adjuvant. At 14 days after the final inoculation, the inoculated mice were challenged with either the A/HongKong/483/97, the A/Vietnam/1194/04, or the A/Indonesia/6/05 strain of H5N1 influenza virus.', 'Compared with noninoculated mice, those inoculated intranasally manifested cross-reactivity of mucosal IgA and serum IgG with H5N1 virus, as well as both a reduced H5N1 virus titer in nasal-wash samples and increased survival, after challenge with H5N1 virus. Subcutaneous inoculation did not induce a cross-reactive IgA response and did not afford protection against H5N1 viral infection.'] Is cross-protection against H5N1 influenza virus infection afforded by intranasal inoculation with seasonal trivalent inactivated influenza vaccine?