title: Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan.
abstract: The 2014/15 influenza season in Japan was characterised by predominant influenza A(H3N2) activity; 99% of influenza A viruses detected were A(H3N2). Subclade 3C.2a viruses were the major epidemic A(H3N2) viruses, and were genetically distinct from A/New York/39/2012(H3N2) of 2014/15 vaccine strain in Japan, which was classified as clade 3C.1. We assessed vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children aged 6 months to 15 years by test-negative case-control design based on influenza rapid diagnostic test. Between November 2014 and March 2015, a total of 3,752 children were enrolled: 1,633 tested positive for influenza A and 42 for influenza B, and 2,077 tested negative. Adjusted VE was 38% (95% confidence intervals (CI): 28 to 46) against influenza virus infection overall, 37% (95% CI: 27 to 45) against influenza A, and 47% (95% CI: -2 to 73) against influenza B. However, IIV was not statistically significantly effective against influenza A in infants aged 6 to 11 months or adolescents aged 13 to 15 years. VE in preventing hospitalisation for influenza A infection was 55% (95% CI: 42 to 64). Trivalent IIV that included A/New York/39/2012(H3N2) was effective against drifted influenza A(H3N2) virus, although vaccine mismatch resulted in low VE.
authors: Keiyu Hospital, Yokohama, Kanagawa, Japan.
authors: Norio
authors: N
authors: Sugaya
authors: Masayoshi
authors: M
authors: Shinjoh
authors: Chiharu
authors: C
authors: Kawakami
authors: Yoshio
authors: Y
authors: Yamaguchi
authors: Makoto
authors: M
authors: Yoshida
authors: Hiroaki
authors: H
authors: Baba
authors: Mayumi
authors: M
authors: Ishikawa
authors: Mio
authors: M
authors: Kono
authors: Shinichiro
authors: S
authors: Sekiguchi
authors: Takahisa
authors: T
authors: Kimiya
authors: Keiko
authors: K
authors: Mitamura
authors: Motoko
authors: M
authors: Fujino
authors: Osamu
authors: O
authors: Komiyama
authors: Naoko
authors: N
authors: Yoshida
authors: Kenichiro
authors: K
authors: Tsunematsu
authors: Atsushi
authors: A
authors: Narabayashi
authors: Yuji
authors: Y
authors: Nakata
authors: Akihiro
authors: A
authors: Sato
authors: Nobuhiko
authors: N
authors: Taguchi
authors: Hisayo
authors: H
authors: Fujita
authors: Machiko
authors: M
authors: Toki
authors: Michiko
authors: M
authors: Myokai
authors: Ichiro
authors: I
authors: Ookawara
authors: Takao
authors: T
authors: Takahashi
mesh_terms: D000293:Adolescent; D000956:Antigens, Viral / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D007564:Japan / Q000453:epidemiology; D008297:Male; D011159:Population Surveillance; D012141:Respiratory Tract Infections / Q000517:prevention & control / Q000821:virology; D012621:Seasons; D016896:Treatment Outcome; D014611:Vaccination / Q000706:statistics & numerical data; D015164:Vaccines, Inactivated
chemical_list: D000956:Antigens, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated
keywords: Influenza; Influenza Virus; Laboratory surveillance; vaccine and immunization; vaccine effectiveness