Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan.
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.
['Sugaya|Norio|N|', 'Shinjoh|Masayoshi|M|', 'Kawakami|Chiharu|C|', 'Yamaguchi|Yoshio|Y|', 'Yoshida|Makoto|M|', 'Baba|Hiroaki|H|', 'Ishikawa|Mayumi|M|', 'Kono|Mio|M|', 'Sekiguchi|Shinichiro|S|', 'Kimiya|Takahisa|T|', 'Mitamura|Keiko|K|', 'Fujino|Motoko|M|', 'Komiyama|Osamu|O|', 'Yoshida|Naoko|N|', 'Tsunematsu|Kenichiro|K|', 'Narabayashi|Atsushi|A|', 'Nakata|Yuji|Y|', 'Sato|Akihiro|A|', 'Taguchi|Nobuhiko|N|', 'Fujita|Hisayo|H|', 'Toki|Machiko|M|', 'Myokai|Michiko|M|', 'Ookawara|Ichiro|I|', 'Takahashi|Takao|T|']
D000293:Adolescent D000956:Antigens, Viral D002648:Child D002675:Child, Preschool D005260:Female D006801:Humans D007223:Infant D053122:Influenza A Virus, H3N2 Subtype D007252:Influenza Vaccines D007251:Influenza, Human D007564:Japan D008297:Male D011159:Population Surveillance D012141:Respiratory Tract Infections D012621:Seasons D016896:Treatment Outcome D014611:Vaccination D015164:Vaccines, Inactivated
Influenza vaccine effectiveness Influenza Virus Laboratory surveillance vaccine and immunization