title: Human papillomavirus (HPV) vaccination coverage in young Australian women is higher than previously estimated: independent estimates from a nationally representative mobile phone survey.
abstract: BACKGROUND
  Accurate estimates of coverage are essential for estimating the population effectiveness of human papillomavirus (HPV) vaccination. Australia has a purpose built National HPV Vaccination Program Register for monitoring coverage, however notification of doses administered to young women in the community during the national catch-up program (2007-2009) was not compulsory. In 2011, we undertook a population-based mobile phone survey of young women to independently estimate HPV vaccination coverage.
  
  
  METHODS
  Randomly generated mobile phone numbers were dialed to recruit women aged 22-30 (age eligible for HPV vaccination) to complete a computer assisted telephone interview. Consent was sought to validate self reported HPV vaccination status against the national register. Coverage rates were calculated based on self report and weighted to the age and state of residence structure of the Australian female population. These were compared with coverage estimates from the register using Australian Bureau of Statistics estimated resident populations as the denominator.
  
  
  RESULTS
  Among the 1379 participants, the national estimate for self reported HPV vaccination coverage for doses 1/2/3, respectively, weighted for age and state of residence, was 64/59/53%. This compares with coverage of 55/45/32% and 49/40/28% based on register records, using 2007 and 2011 population data as the denominators respectively. Some significant differences in coverage between the states were identified. 20% (223) of women returned a consent form allowing validation of doses against the register and provider records: among these women 85.6% (538) of self reported doses were confirmed.
  
  
  CONCLUSIONS
  We confirmed that coverage rates for young women vaccinated in the community (at age 18-26 years) are underestimated by the national register and that under-notification is greater for second and third doses. Using 2011 population estimates, rather than estimates contemporaneous with the program rollout, reduces register-based coverage estimates further because of large population increases due to immigration since the program.
authors: National HPV Vaccination Program Register, VCS Inc., PO Box 310, East Melbourne 8002, Victoria, Australia; Discipline of Paediatrics and Child Health, University of Sydney, Locked Bag 4001, Westmead 2145, New South Wales, Australia; Melbourne School of Population and Global Health, 207 Bouverie Street, The University of Melbourne, Parkville, Victoria 2010, Australia. Electronic address: jbrother@vcs.org.au.
authors: Julia M L
authors: JM
authors: Brotherton
authors: The Kirby Institute, University of New South Wales, Sydney 2052, New South Wales, Australia. Electronic address: bette.liu@unsw.edu.au.
authors: Bette
authors: B
authors: Liu
authors: The Kirby Institute, University of New South Wales, Sydney 2052, New South Wales, Australia; Sydney Sexual Health Centre, Sydney Hospital, PO Box 1614, Sydney 2001, New South Wales, Australia. Electronic address: bdonovan@kirby.unsw.edu.au.
authors: Basil
authors: B
authors: Donovan
authors: The Kirby Institute, University of New South Wales, Sydney 2052, New South Wales, Australia. Electronic address: jkaldor@kirby.unsw.edu.au.
authors: John M
authors: JM
authors: Kaldor
authors: National HPV Vaccination Program Register, VCS Inc., PO Box 310, East Melbourne 8002, Victoria, Australia. Electronic address: msaville@vcs.org.au.
authors: Marion
authors: M
authors: Saville
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D030361:Papillomavirus Infections / Q000517:prevention & control; D053918:Papillomavirus Vaccines / Q000008:administration & dosage*; D014611:Vaccination / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D053918:Papillomavirus Vaccines
keywords: Australia; Human papillomavirus (HPV); Vaccination coverage