Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Epidemiology and Infection 2959-2964 Influenza A virology (human) and epidemiology zoonoses VIET NAM 2015 fdi:010065387 ENG Epidemiology and Infection 0950-2688 ISI:000362955500005 14 10.1017/s0950268815000187 https://www.documentation.ird.fr/hor/fdi:010065387 https://www.documentation.ird.fr/intranet/publi/2015/11/010065387.pdf 143 Horizon (IRD) A reassortant swine-origin A(H3N2) virus (A/swine/BinhDuong/03-9/2010) was detected through swine surveillance programmes in southern Vietnam in 2010. This virus contains haemagglutinin and neuraminidase genes from a human A(H3N2) virus circulating around 2004-2006, and the internal genes from triple-reassortant swine influenza A viruses (IAVs). To assess population susceptibility to this virus we measured haemagglutination inhibiting (HI) titres to A/swine/BinhDuong/03-9/2010 and to seasonal A/Perth/16/2009 for 947 sera collected from urban and rural Vietnamese people during 2011-2012. Seroprevalence (HI >= 40) was high and similar for both viruses, with 62.6% [95% confidence interval (CI) 59.4-65.7] against A/Perth/16/2009 and 54.6% (95% CI 51.4-57.8%) against A/swine/BinhDuong/03-9/2010, and no significant differences between urban and rural participants. Children aged <5 years lacked antibodies to the swine origin H3 virus despite high seroprevalence for A/Perth/16/2009. These results reveal vulnerability to infection to this contemporary swine IAV in children aged <5 years; however, cross-reactive immunity in adults would likely limit epidemic emergence potential. 052 UR224 Vietnam