Effectiveness of inactivated influenza vaccine in children by vaccine dose, 2013–18

Masayoshi Shinjoh, Norio Sugaya, Munehiro Furuichi, Eriko Araki, Naonori Maeda, Kyohei Isshiki, Takuma Ohnishi, Shoko Nakamura, Go Yamada, Atsushi Narabayashi, Mitsuhiro Nishida, Nobuhiko Taguchi, Yuji Nakata, Makoto Yoshida, Kenichiro Tsunematsu, Meiwa Shibata, Takeshi Munenaga, Yasuhiro Hirano, Ichiro Ookawara, Shinichiro SekiguchiYasuaki Kobayashi, Yoshio Yamaguchi, Naoko Yoshida, Keiko Mitamura, Takao Takahashi

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Objectives: We assessed the vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) by vaccine dose in children aged 6 months to 12 years for whom two doses are recommended in Japan to ascertain the appropriate vaccine doses. Methods: VE was assessed according to a test-negative case-control design based on rapid influenza diagnostic test (RIDT) results. Children aged 6 months to 12 years with a fever ≥38 °C who had received an RIDT in outpatient clinics of 24 hospitals were enrolled for all five seasons since 2013/14. VE by vaccine dose (none vs. once or twice, and once vs. twice) was analyzed. Results: In the dose analysis, 20,033 children were enrolled. Both one- and two-dose regimens significantly reduced cases in preventing any influenza, influenza A, and influenza B, but there was no significant difference in adjusted VE between one- and two-dose regimens overall (adjusted OR, 0.560 [95% CI, 0.505–0.621], 0.550 [95% CI, 0.516–0.586]), 0.549 [95% CI, 0.517–0.583], and 1.014 [95% CI, 0.907–1.135], for none vs. once, none vs. twice, none vs. once or twice, and once vs. twice for any influenza, respectively). Both one- and two-dose regimens significantly reduced cases with any influenza and influenza A every season. Also, both regimens significantly reduced cases of any influenza, influenza A, and influenza B among children aged 1–12 years, especially among those aged 1–5 years. In the 2013/14, 2015/16, and 2016/17 seasons, however, only the two-dose regimen was significantly effective in preventing influenza B. Both one- and two-dose regimens significantly reduced cases involving hospitalization due to any influenza and influenza A. Conclusions: Both one- and two-doses regimens of IIV were effective in preventing influenza for children aged 6 months to 12 years. The two-dose regimen was more effective against influenza B in some seasons.

Original languageEnglish
Pages (from-to)4047-4054
Number of pages8
JournalVaccine
Volume37
Issue number30
DOIs
Publication statusPublished - 2019 Jul 9

Keywords

  • Children
  • Effectiveness
  • Hospitalization
  • Influenza vaccine
  • Test-negative case control
  • Vaccine dose

ASJC Scopus subject areas

  • Molecular Medicine
  • Immunology and Microbiology(all)
  • veterinary(all)
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases

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