title: Population susceptibility to a variant swine-origin influenza virus A(H3N2) in Vietnam, 2011-2012.
abstract: 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.
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: L N M
authors.initials: LN
authors.lastname: Hoa
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: J E
authors.initials: JE
authors.lastname: Bryant
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: M
authors.initials: M
authors.lastname: Choisy
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: L A
authors.initials: LA
authors.lastname: Nguyet
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: N T
authors.initials: NT
authors.lastname: Bao
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: N H
authors.initials: NH
authors.lastname: Trang
authors.affiliation: Hanoi Medical University,Hanoi,Vietnam.
authors.forename: N T K
authors.initials: NT
authors.lastname: Chuc
authors.affiliation: Hanoi Medical University,Hanoi,Vietnam.
authors.forename: T K
authors.initials: TK
authors.lastname: Toan
authors.affiliation: Influenza and Prion Diseases Research Center,National Institute of Animal Health,National Agriculture and Food Research Organization (NARO),Ibaraki,Japan.
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.affiliation: Influenza and Prion Diseases Research Center,National Institute of Animal Health,National Agriculture and Food Research Organization (NARO),Ibaraki,Japan.
authors.forename: N
authors.initials: N
authors.lastname: Takemae
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: P
authors.initials: P
authors.lastname: Horby
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: H
authors.initials: H
authors.lastname: Wertheim
authors.affiliation: Oxford University Clinical Research Unit and Wellcome Trust Major Overseas Programme,Vietnam.
authors.forename: A
authors.initials: A
authors.lastname: Fox
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology* / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009976:Orthomyxoviridae Infections / Q000821:virology; D016865:Reassortant Viruses / Q000276:immunology* / Q000302:isolation & purification; D016036:Seroepidemiologic Studies; D034421:Sus scrofa / Q000821:virology; D013552:Swine; D013553:Swine Diseases / Q000821:virology; D014744:Vietnam / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral
keywords: Influenza A; virology (human) and epidemiology; zoonoses