Efficacy and safety of a live attenuated influenza vaccine in Chinese healthy children aged 3-17 years in one study center of a randomized, double-blind, placebo-controlled phase 3 clinical trial, 2016/17 season

Vaccine. 2020 Aug 27;38(38):5979-5986. doi: 10.1016/j.vaccine.2020.07.019. Epub 2020 Jul 31.

Abstract

Background: No data on the safety and efficacy of a live attenuated influenza vaccine in China have ever been reported.

Methods: At a site of a phase 3 randomized, double-blind, placebo-controlled clinical trial in eastern China, eligible healthy children aged 3-17 years underwent randomization to receive live attenuated vaccine or placebo at a ratio of 1:1. The primary objective of the study was the prevention of laboratory-confirmed influenza illness during the surveillance period, starting on day 15 after vaccination.

Results: A total of 2000 participants were enrolled, with 998 receiving the vaccine and 1001 receiving placebo. Sixty-four cases of influenza-like illness were observed, of which, 44 were laboratory-confirmed (12 in vaccine group versus 32 in placebo group). Vaccine efficacy was 62.5% (95%CI: 27.6-80.6) against all types of influenza and 63.3% (95%CI: 27.5-81.5) against influenza H3N2 illness. 11 severe adverse events reported (7 in LAIV group versus 4 in placebo group) were all deemed to be non-vaccine-related. Adverse events occurred in 412 (41.3%) participants in the vaccine group versus 389 (38.9%; p = 0.274) participants in the placebo group. Significant increase incidence of fever was observed in participants in the vaccine group, especially in those aged 3-9 years.

Conclusions: The live attenuated influenza vaccine showed good efficacy and safety among 3- to 17-year-olds children during the 2016-2017 season at a site in eastern China. Clinical Trial Registry Number: NCT02964065.

Keywords: Efficacy; Laboratory-confirmed influenza illness; Live attenuated influenza vaccine; Placebo-controlled; School-age children.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • China / epidemiology
  • Double-Blind Method
  • Humans
  • Influenza A Virus, H3N2 Subtype
  • Influenza Vaccines* / adverse effects
  • Influenza, Human* / prevention & control
  • Seasons
  • Vaccines, Attenuated / adverse effects

Substances

  • Influenza Vaccines
  • Vaccines, Attenuated

Associated data

  • ClinicalTrials.gov/NCT02964065