Influenza vaccine efficacy in young children attending childcare: A randomised controlled trial

J Paediatr Child Health. 2017 Jan;53(1):47-54. doi: 10.1111/jpc.13313. Epub 2016 Sep 4.


Aim: Influenza causes a substantial burden in young children. Vaccine efficacy (VE) data are limited in this age group. We examined trivalent influenza vaccine (TIV) efficacy and safety in young children attending childcare.

Methods: A double-blind, randomised controlled trial in children aged 6 to <48 months was conducted with recruitment from Sydney childcare centres in 2011. Children were randomised to receive two doses of TIV or control hepatitis A vaccine. Efficacy was evaluated against polymerase chain reaction-confirmed influenza using parent-collected nose/throat swabs during influenza-like-illness. Safety outcomes were assessed during 6 months of follow-up.

Results: Fifty-seven children were allocated to influenza vaccine and 67 to control; all completed the study. The influenza attack rate was 1.8 vs 13.4% in the TIV and control groups, respectively; VE 87% (95%CI: 0-98%). For children aged 24 to <48 months, 0 vs 8 (18.6%) influenza infections occurred in the TIV and control groups respectively, giving a VE of 100% (16-100%). Efficacy was not shown in children 6 to <24 months, probably due to insufficient power. Injection site and systemic adverse events were mostly mild to moderate with no significant differences, apart from more mild diarrhoea following dose 2 in TIV recipients (11.8 vs 0%).

Conclusions: Influenza vaccine appeared efficacious in the subgroup of children aged 24 to <48 months, although caution is required due to the small number of participants. There were no serious adverse events and most parents would vaccinate again. Influenza vaccination in a childcare setting could be valuable and a larger confirmatory study would be helpful.

Keywords: childcare; children; influenza; randomised controlled trial; vaccination.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Child Care*
  • Child, Preschool
  • Double-Blind Method
  • Female
  • Hepatitis A / prevention & control
  • Hepatitis A Vaccines / administration & dosage
  • Humans
  • Infant
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / standards*
  • Influenza, Human / prevention & control*
  • Male
  • Middle Aged
  • Registries
  • Treatment Outcome
  • Vaccines, Inactivated


  • Hepatitis A Vaccines
  • Influenza Vaccines
  • Vaccines, Inactivated