title: Evaluation of Australia's varicella vaccination program for children and adolescents.
abstract: OBJECTIVE
  This paper examines how the monovalent varicella vaccine for children, with an adolescent catch-up dose, was introduced into Australia's National Immunisation Program (NIP), focusing on programme implementation.
  
  
  METHODS
  Semi-structured interviews were conducted with key informants involved in programme implementation. Key themes from interviews were identified through content analysis. Childhood coverage was assessed using data from the Australian Childhood Immunisation Register (ACIR) with adolescent coverage obtained from state/territory immunisation programmes. Seroprevalence data were analysed from national serosurveys conducted before and after programme commencement.
  
  
  RESULTS
  Implementation challenges for both parents and providers included: (a) parental report of previous infection as an exclusion criterion; (b) introducing a vaccine on its own at 18 months of age; and (c) adding the adolescent dose into existing school-based vaccination programmes with parental reported exclusion criteria. Despite these challenges, coverage rapidly reached 83% by 24 months of age and 30-33% for the adolescent catch-up dose. When considered in conjunction with estimated pre-vaccination natural immunity in both target groups (20% and 83%, respectively) coverage can be considered high. The serosurvey under-estimated coverage in 2-year-old children but was useful to assess trends in population immunity.
  
  
  CONCLUSIONS
  The introduction of a single dose of monovalent varicella vaccine at 18 months of age and a school-based catch-up programme at 11-13 years of age successfully achieved high coverage, notwithstanding some challenges. Reported natural infection has been an exclusion criterion for vaccination, but as the programme matures and circulation of wild-type virus decreases, the need for this warrants consideration. There is a need for sensitive laboratory assays to measure vaccine-induced immunity at a population level.
authors.affiliation: National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, The Children's Hospital at Westmead, Cnr Hawkesbury Road and Hainsworth Street, Westmead, New South Wales 2145, Australia.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Ward
authors.forename: Aditi
authors.initials: A
authors.lastname: Dey
authors.forename: Brynley
authors.initials: B
authors.lastname: Hull
authors.forename: Helen E
authors.initials: HE
authors.lastname: Quinn
authors.forename: Kristine
authors.initials: K
authors.lastname: Macartney
authors.forename: Robert
authors.initials: R
authors.lastname: Menzies
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia / Q000453:epidemiology; D002644:Chickenpox / Q000453:epidemiology* / Q000517:prevention & control*; D019433:Chickenpox Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006302:Health Services Research; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D014611:Vaccination / Q000379:methods*; D055815:Young Adult
chemical_list: D019433:Chickenpox Vaccine