title: Pilot study of influenza vaccine effectiveness in urban Australian children attending childcare.
abstract: BACKGROUND
  Influenza outbreaks in the childcare setting are a significant cause of excess winter morbidity. This study explored methods of follow up and sample collection for a proposed randomised controlled trial of influenza vaccination in children attending childcare.
  
  
  METHODS
  The study was conducted in four Sydney childcare centres during 2007. Healthy children aged 6-59 months eligible for vaccination were recruited in two centres, with another two acting as controls. Data on influenza-like illness (ILI: ≥37.8°C plus at least one respiratory symptom) occurrence were collected weekly. In those children with an ILI, parents were asked to collect nasal swabs and send via surface mail for viral polymerase chain reaction. Vaccine efficacy (VE) for ILI was estimated overall and for subgroups aged 6-23 and 24-59 months using the formula VE = 1 - relative risk (RR).
  
  
  RESULTS
  Sixty-three per cent (151/238) of eligible children had parents give consent. Sixty-three children received influenza vaccine and 88 participated as controls. Of 26 specimens returned, a virus was detected in 18 (69%); none with influenza. Two symptomatic children had positive near-patient influenza tests in general practice (one a vaccine failure). The RR with 95% confidence interval in all children and those aged 6-23 months were less than one, 0.56 (0.32-1.02) and 0.46 (0.15-1.45), respectively.
  
  
  CONCLUSIONS
  This study demonstrated the feasibility and utility of parent-collected and mailed respiratory specimens for VE research in the childcare setting. Two-thirds of parent-collected swabs proved positive for at least one virus. Finding ways to reduce reluctance of parents to submit samples could improve the representativeness of samples collected and the power of the study. No evidence was found for influenza VE, but point estimates were in the direction of protection.
authors.affiliation: National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, The Children's Hospital, Westmead, Australia. keviny@chw.edu.au
authors.forename: J Kevin
authors.initials: JK
authors.lastname: Yin
authors.forename: Monica M
authors.initials: MM
authors.lastname: Lahra
authors.forename: Mary
authors.initials: M
authors.lastname: Iskander
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Lambert
authors.forename: Leon
authors.initials: L
authors.lastname: Heron
authors.forename: Michael D
authors.initials: MD
authors.lastname: Nissen
authors.forename: Laura
authors.initials: L
authors.lastname: Rost
authors.forename: Jennifer
authors.initials: J
authors.lastname: Murphy
authors.forename: Theo P
authors.initials: TP
authors.lastname: Sloots
authors.forename: Robert
authors.initials: R
authors.lastname: Booy
mesh_terms: D002654:Child Care; D002675:Child, Preschool; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D009980:Influenza A virus / Q000302:isolation & purification; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000503:physiopathology / Q000517:prevention & control*; D008297:Male; D009517:New South Wales; D017063:Outcome Assessment, Health Care; D010865:Pilot Projects; D011159:Population Surveillance / Q000379:methods; D014505:Urban Population
chemical_list: D007252:Influenza Vaccines