title: Population-level impact of the bivalent, quadrivalent, and nonavalent human papillomavirus vaccines: a model-based analysis.
abstract: BACKGROUND
  Bivalent and quadrivalent human papillomavirus (HPV) vaccines are now licensed in several countries. Furthermore, clinical trials examining the efficacy of a nonavalent vaccine are underway. We aimed to compare the potential population-level effectiveness of the bivalent, quadrivalent, and candidate nonavalent HPV vaccines.
  
  
  METHODS
  We developed an individual-based, transmission-dynamic model of HPV infection and disease in a population stratified by age, gender, sexual activity, and screening behavior. The model was calibrated to highly stratified sexual behavior, HPV epidemiology, and cervical screening data from Canada.
  
  
  RESULTS
  Under base case assumptions, vaccinating 12-year-old girls (70% coverage) with the bivalent (quadrivalent) vaccine is predicted to reduce the cumulative incidence of anogenital warts (AGWs) by 0.0% (72.1%), diagnosed cervical intraepithelial neoplasia lesions 2 and 3 (CIN2 and -3) by 51.0% (46.1%), and cervical squamous cell carcinoma (SCC) by 31.9% (30.5%), over 70 years. Changing from a bivalent (quadrivalent) to a nonavalent vaccine is predicted to reduce the cumulative number of AGW episodes by an additional 66.7% (0.0%), CIN2 and -3 episodes by an additional 9.3% (12.5%), and SCC cases by an additional 4.8% (6.6%) over 70 years. Differences in predicted population-level effectiveness between the vaccines were most sensitive to duration of protection and the time horizon of analysis. The vaccines produced similar effectiveness at preventing noncervical HPV-related cancers.
  
  
  CONCLUSIONS
  The bivalent vaccine is expected to be slightly more effective at preventing CIN2 and -3 and SCC in the longer term, whereas the quadrivalent vaccine is expected to substantially reduce AGW cases shortly after the start of vaccination programs. Switching to a nonavalent vaccine has the potential to further reduce precancerous lesions and cervical cancer.
authors.affiliation: Centre de recherche FRSQ du CHA universitaire de Québec, Québec, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Van de Velde
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Boily
authors.forename: Mélanie
authors.initials: M
authors.lastname: Drolet
authors.forename: Eduardo L
authors.initials: EL
authors.lastname: Franco
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Mayrand
authors.forename: Erich V
authors.initials: EV
authors.lastname: Kliewer
authors.forename: François
authors.initials: F
authors.lastname: Coutlée
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Laprise
authors.forename: Talía
authors.initials: T
authors.lastname: Malagón
authors.forename: Marc
authors.initials: M
authors.lastname: Brisson
mesh_terms: D000293:Adolescent; D000328:Adult; D002170:Canada / Q000453:epidemiology; D002648:Child; D003218:Condylomata Acuminata / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D015233:Models, Statistical; D030361:Papillomavirus Infections / Q000150:complications / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D053918:Papillomavirus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D012725:Sexual Behavior; D002578:Uterine Cervical Dysplasia / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D055815:Young Adult
chemical_list: D053918:Papillomavirus Vaccines