title: Modeling the impact of quadrivalent HPV vaccination on the incidence of Pap test abnormalities in the United States.
abstract: BACKGROUND
  We present data on Pap test results and HPV prevalence from the HPV Sentinel Surveillance project, a multiyear surveillance project enrolling women from a diverse set of 26 clinics throughout the US from 2003 to 2005. We use mathematical modeling to illustrate the potential timing and magnitude of decreases in Pap test abnormalities in sexually transmitted disease (STD), family planning, and primary care clinics in the US as a result of HPV vaccination.
  
  
  METHODS
  The probability of an abnormal Pap result was based on three factors: (1) infection with HPV 16/18, or both; (2) infection with high-risk HPV types other than HPV 16/18; and (3) infection with HPV 6/11, or both. We estimated the relative reduction in the probability of an abnormal Pap result over the first 25 years of a female-only, quadrivalent HPV vaccination program, compared to a scenario of no HPV vaccination in which the probability of abnormal Pap results was assumed constant.
  
  
  RESULTS
  The probability of an abnormal Pap result ranged from 7.0% for the lowest risk group (those without any high-risk HPV types and without HPV 6/11) to 45.2% for the highest risk group (those with HPV 16/18 and at least one other high-risk HPV type). Estimated reductions in abnormal Pap results among women in the 21- to 29-year age group were 0.8%, 10.2%, and 11.3% in years 5, 15, and 25 of the vaccine program respectively, in the lower vaccine coverage scenario, and 7.4%, 21.4%, and 22.2%, respectively, in the higher coverage scenario.
  
  
  CONCLUSIONS
  Our results suggest that HPV vaccination will have a discernable impact on the probability of Pap abnormalities, but the timing and magnitude of the reduction will depend substantially on vaccine coverage and the degree of cross-protection against high risk HPV types other than HPV 16/18.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, USA. hbc7@cdc.gov
authors.forename: Harrell W
authors.initials: HW
authors.lastname: Chesson
authors.forename: Elaine W
authors.initials: EW
authors.lastname: Flagg
authors.forename: Laura
authors.initials: L
authors.lastname: Koutsky
authors.forename: Katherine
authors.initials: K
authors.lastname: Hsu
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Unger
authors.forename: Judith C
authors.initials: JC
authors.lastname: Shlay
authors.forename: Peter
authors.initials: P
authors.lastname: Kerndt
authors.forename: Khalil G
authors.initials: KG
authors.lastname: Ghanem
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Zenilman
authors.forename: Michael
authors.initials: M
authors.lastname: Hagensee
authors.forename: Hillard
authors.initials: H
authors.lastname: Weinstock
authors.forename: S Deblina
authors.initials: SD
authors.lastname: Datta
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D062665:Epidemiological Monitoring; D005260:Female; D000068857:Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18; D006801:Humans; D015994:Incidence; D018448:Models, Immunological; D065006:Papanicolaou Test / Q000706:statistics & numerical data*; D030361:Papillomavirus Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000008:administration & dosage*; D011247:Pregnancy; D015995:Prevalence; D014481:United States / Q000453:epidemiology; D014611:Vaccination / Q000379:methods*; D055815:Young Adult
chemical_list: D000068857:Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18; D053918:Papillomavirus Vaccines