title: Incident cervical HPV infections in young women: transition probabilities for CIN and infection clearance.
abstract: BACKGROUND
  We describe transition probabilities for incident human papillomavirus (HPV) 16/18/31/33/35/45/52/58/59 infections and cervical intraepithelial neoplasia (CIN) 1 lesions.
  
  
  METHODS
  Women ages 16 to 23 years underwent cytology and cervical swab PCR testing for HPV at approximately 6-month intervals for up to 4 years in the placebo arm of an HPV vaccine trial. The cumulative proportion of incident HPV infections with diagnosed CIN, clearing (infection undetectable), or persisting without CIN, were estimated.
  
  
  RESULTS
  Most incident infections cleared, without detection of CIN, ranging at 36 months from 66.9% for HPV31 to 91.1% for HPV59. There was little variation in the 36-month proportion of incident HPV16, 18, and 31 infections followed by a CIN1 lesion positive for the relevant HPV type (range 16.7%-18.6%), with lower risks for HPV59 (6.4%) and HPV33 (2.9%). Thirty-six-month transition probabilities for CIN2 ranged across types from 2.2% to 9.1%; however, the number of events was generally too small for statistically significant differences to be seen across types for this endpoint, or CIN3.
  
  
  CONCLUSIONS
  Some incident HPV types appear more likely to result in diagnosed CIN1 than others. The relative predominance of HPV16, vis-à-vis some other high-risk HPV types (e.g., HPV33) in prevalent CIN2/3, appears more directly associated with relatively greater frequency of incident HPV16 infections within the population, than a higher risk of infection progression to CIN2/3.
  
  
  CONCLUSIONS
  Nearly all incident HPV infections either manifest as detectable CIN or become undetectable within 36 months. Some HPV types (e.g., 16 and 33) appear to have similar risk of CIN2/3 despite widely varied incidence.
authors.affiliation: Merck and Co., Inc., UG1C-60, PO Box 1000, North Wales, PA 19454-10099, USA. ralph_insinga@merck.com
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Insinga
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Perez
authors.forename: Cosette M
authors.initials: CM
authors.lastname: Wheeler
authors.forename: Laura A
authors.initials: LA
authors.lastname: Koutsky
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Garland
authors.forename: Sepp
authors.initials: S
authors.lastname: Leodolter
authors.forename: Elmar A
authors.initials: EA
authors.lastname: Joura
authors.forename: Daron G
authors.initials: DG
authors.lastname: Ferris
authors.forename: Marc
authors.initials: M
authors.lastname: Steben
authors.forename: Mauricio
authors.initials: M
authors.lastname: Hernandez-Avila
authors.forename: Darron R
authors.initials: DR
authors.lastname: Brown
authors.forename: Elamin
authors.initials: E
authors.lastname: Elbasha
authors.forename: Nubia
authors.initials: N
authors.lastname: Muñoz
authors.forename: Jorma
authors.initials: J
authors.lastname: Paavonen
authors.forename: Richard M
authors.initials: RM
authors.lastname: Haupt
mesh_terms: D000293:Adolescent; D000328:Adult; D002584:Cervix Uteri / Q000821:virology*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007390:International Agencies; D027383:Papillomaviridae / Q000472:pathogenicity*; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology; D053918:Papillomavirus Vaccines / Q000627:therapeutic use; D010919:Placebos; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors; D015996:Survival Rate; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology* / Q000821:virology; D055815:Young Adult; D002578:Uterine Cervical Dysplasia / Q000453:epidemiology* / Q000821:virology
chemical_list: D053918:Papillomavirus Vaccines; D010919:Placebos