title: The age distribution of type-specific high-risk human papillomavirus incidence in two population-based screening trials.
abstract: BACKGROUND
  Age- and type-specific high-risk human papillomavirus (hrHPV) incidence estimates in screen-eligible women are relevant from a public health perspective because they provide an indication of the effect of vaccination on the occurrence of screen-positives in HPV-based screening. However, limited data from women over 25 years of age are available.
  
  
  METHODS
  In 24,105 hrHPV-negative women participating in Dutch (Population-Based Screening Study Amsterdam: POBASCAM) and Italian (New Technologies for Cervical Cancer: NTCC) population-based randomized controlled screening trials the age- and type-specific distribution of incident hrHPV infections detected at the next screening round was assessed. HPV types were grouped into vaccine (bivalent: HPV16/18; polyvalent HPV16/18/31/33/45/52/58) and nonvaccine types.
  
  
  RESULTS
  The incidence of screen-detected hrHPV among women ages 29 to 56 years was 2.54% (95% confidence interval, 2.30-2.78) in POBASCAM and 2.77% (2.36-3.19) in NTCC. In both studies, the incidence of bivalent, polyvalent, and nonpolyvalent infections decreased with age (P < 0.0001). Among women with incident infection(s), vaccine-type positivity changed quadratically with age, in particular for the polyvalent vaccine (P values: POBASCAM: bivalent 0.264, polyvalent 0.038; NTCC bivalent 0.039, polyvalent 0.005). However, more than 20% and 50% of women with incident hrHPV were positive for bivalent and polyvalent vaccine types, respectively, in all ages in both studies.
  
  
  CONCLUSIONS
  We observed decreasing age trends of hrHPV vaccine and nonvaccine type incidences and age-related differences in the vaccine-type positivity among women with incident infections. Most importantly, hrHPV infections continued to be detected in all ages and the contribution of vaccine types remained substantial.
  
  
  CONCLUSIONS
  Our results indicate a considerable reduction of new hrHPV infections in vaccinated cohorts, ensuing revision of screening guidelines.
authors.affiliation: Department of Epidemiology & Biostatistics, VU University Medical Centre, Amsterdam, the Netherlands. n.veldhuijzen@vumc.nl.
authors.forename: Nienke J
authors.initials: NJ
authors.lastname: Veldhuijzen
authors.affiliation: Department of Epidemiology & Biostatistics, VU University Medical Centre, Amsterdam, the Netherlands.
authors.forename: Johannes
authors.initials: J
authors.lastname: Berkhof
authors.affiliation: Cancer Epidemiology Unit, CERMS, University of Turin, Turin, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Gillio-Tos
authors.affiliation: Cancer Epidemiology Unit, CERMS, University of Turin, Turin, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: De Marco
authors.affiliation: Cancer Prevention and Research Institute (ISPO), Florence, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Carozzi
authors.affiliation: Veneto Institute of Oncology IOV-IRCCS, Padua, Italy.
authors.forename: Annarosa
authors.initials: A
authors.lastname: Del Mistro
authors.affiliation: Department of Pathology, VU University Medical Centre (VUmc), Amsterdam, the Netherlands.
authors.forename: Peter J F
authors.initials: PJ
authors.lastname: Snijders
authors.affiliation: Department of Pathology, VU University Medical Centre (VUmc), Amsterdam, the Netherlands.
authors.forename: Chris J L M
authors.initials: CJ
authors.lastname: Meijer
authors.affiliation: Center for Cancer Epidemiology and Prevention, AO City of Health and Science, Turin, Italy.
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Ronco
mesh_terms: D000328:Adult; D000367:Age Factors; D003625:Data Collection; D005260:Female; D006801:Humans; D015994:Incidence; D008403:Mass Screening; D008875:Middle Aged; D027383:Papillomaviridae / Q000235:genetics*; D030361:Papillomavirus Infections / Q000821:virology*; D012307:Risk Factors