title: Type-specific duration of human papillomavirus infection: implications for human papillomavirus screening and vaccination.
abstract: BACKGROUND
  Understanding the duration of human papillomavirus (HPV) infection may help find suitable end points for vaccine trials and testing intervals in screening studies. We studied genotype-specific infection duration among 2462 women enrolled in the Ludwig-McGill cohort study.
  
  
  METHODS
  Cervical specimens collected every 4-6 months were tested by a polymerase chain reaction protocol. Actuarial techniques were used to estimate the duration of HPV infection and to investigate the influence of age, number of sexual partners, and coinfection with multiple HPV types.
  
  
  RESULTS
  At enrollment, the prevalence of infection with high-risk HPV types was 10.6%, and the prevalence of infection with low-risk HPV types was 6.1%; incidence rates were 6.1 and 5.0 infections per 1000 women-months, respectively. Prevalent infections took longer to clear than incident infections (mean time to clearance, 18.6 months vs. 13.5 months). The mean duration of incident infection with high- and low-risk HPV varied according to the analytic approach used to measure this variable and showed considerable variation by HPV type (range, 5.1-15.4 months). Age and number of partners did not influence infection duration, whereas coinfection was associated with increased infection duration. The mean duration of HPV-16 monoinfection was 11.0 months, and the mean duration of HPV-16 coinfection was 15.4 months.
  
  
  CONCLUSIONS
  There was considerable variation among HPV types with regard to the duration of infection. Coinfection with multiple types contributed to an increased infection duration.
authors.affiliation: Division of Cancer Epidemiology, McGill University, Montreal, Canada.
authors.forename: Helen
authors.initials: H
authors.lastname: Trottier
authors.forename: Salaheddin
authors.initials: S
authors.lastname: Mahmud
authors.forename: José Carlos M
authors.initials: JC
authors.lastname: Prado
authors.forename: Joao S
authors.initials: JS
authors.lastname: Sobrinho
authors.forename: Maria C
authors.initials: MC
authors.lastname: Costa
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rohan
authors.forename: Luisa L
authors.initials: LL
authors.lastname: Villa
authors.forename: Eduardo L
authors.initials: EL
authors.lastname: Franco
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002584:Cervix Uteri / Q000821:virology; D015331:Cohort Studies; D015897:Comorbidity; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008875:Middle Aged; D027383:Papillomaviridae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology*; D016133:Polymerase Chain Reaction / Q000379:methods; D015995:Prevalence; D012725:Sexual Behavior; D013997:Time Factors
chemical_list: D004279:DNA, Viral