PLoS ONE (Jan 2015)

Effectiveness of Trivalent Inactivated Influenza Vaccine in Children Estimated by a Test-Negative Case-Control Design Study Based on Influenza Rapid Diagnostic Test Results.

  • Masayoshi Shinjoh,
  • Norio Sugaya,
  • Yoshio Yamaguchi,
  • Yuka Tomidokoro,
  • Shinichiro Sekiguchi,
  • Keiko Mitamura,
  • Motoko Fujino,
  • Hiroyuki Shiro,
  • Osamu Komiyama,
  • Nobuhiko Taguchi,
  • Yuji Nakata,
  • Naoko Yoshida,
  • Atsushi Narabayashi,
  • Michiko Myokai,
  • Masanori Sato,
  • Munehiro Furuichi,
  • Hiroaki Baba,
  • Hisayo Fujita,
  • Akihiro Sato,
  • Ichiro Ookawara,
  • Kenichiro Tsunematsu,
  • Makoto Yoshida,
  • Mio Kono,
  • Fumie Tanaka,
  • Chiharu Kawakami,
  • Takahisa Kimiya,
  • Takao Takahashi,
  • Satoshi Iwata,
  • Keio Pediatric Influenza Research Group

DOI
https://doi.org/10.1371/journal.pone.0136539
Journal volume & issue
Vol. 10, no. 8
p. e0136539

Abstract

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We assessed vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza in children 6 months to 15 years of age in 22 hospitals in Japan during the 2013-14 season. Our study was conducted according to a test-negative case-control design based on influenza rapid diagnostic test (IRDT) results. Outpatients who came to our clinics with a fever of 38 °C or over and had undergone an IRDT were enrolled in this study. Patients with positive IRDT results were recorded as cases, and patients with negative results were recorded as controls. Between November 2013 and March 2014, a total of 4727 pediatric patients (6 months to 15 years of age) were enrolled: 876 were positive for influenza A, 66 for A(H1N1)pdm09 and in the other 810 the subtype was unknown; 1405 were positive for influenza B; and 2445 were negative for influenza. Overall VE was 46% (95% confidence interval [CI], 39-52). Adjusted VE against influenza A, influenza A(H1N1)pdm09, and influenza B was 63% (95% CI, 56-69), 77% (95% CI, 59-87), and 26% (95% CI, 14-36), respectively. Influenza vaccine was not effective against either influenza A or influenza B in infants 6 to 11 months of age. Two doses of influenza vaccine provided better protection against influenza A infection than a single dose did. VE against hospitalization influenza A infection was 76%. Influenza vaccine was effective against influenza A, especially against influenza A(H1N1)pdm09, but was much less effective against influenza B.