title: Impact of a prophylactic quadrivalent human papillomavirus (types 6, 11, 16, 18) L1 virus-like particle vaccine in a sexually active population of North American women.
abstract: OBJECTIVE
  The purpose of this study was to inform policy regarding human papillomavirus (HPV) vaccination in North America. We measured the clinical impact of HPV-6/-11/-16/-18 vaccination in North American women.
  
  
  METHODS
  The study enrolled 21,954 women, the majority aged 16-25, across 5 studies of a quadrivalent HPV vaccine or its HPV-16 vaccine prototype. The North American subjects (n = 5996) were pooled from these trials, and the prevalence of HPV-6/-11/-16/-18 exposure was measured. The impact of vaccination on the burden of anogenital HPV lesions in an intention-to-treat population (regardless of enrollment HPV status) was calculated.
  
  
  RESULTS
  At enrollment, the median age was 20 years; 13% of the women had had a Papanicolaou test abnormality, and 76% of the women had negative tests results for all 4 vaccine HPV types. With approximately 3 years of follow-up evaluations in the intention-to-treat population (regardless of enrollment HPV status), vaccination reduced the rate of HPV-16- and -18-related precancers and HPV-6/-11/-16/-18-related genital lesions by 66.4% (95% CI, 42.7%-81.1%) and 57.7% (95% CI, 27.3%-76.3%), respectively.
  
  
  CONCLUSIONS
  The administration of HPV vaccine to sexually active North American women reduced the burden of HPV-6/-11/-16/-18-related disease. Catch-up vaccination programs in this population are warranted.
authors.affiliation: Department of Vaccines and Biologics Clinical Research, Merck Research Laboratories, North Wales, PA 19454-1099, USA. Eliav_barr@merck.com
authors.forename: Eliav
authors.initials: E
authors.lastname: Barr
authors.forename: Christine K
authors.initials: CK
authors.lastname: Gause
authors.forename: Oliver M
authors.initials: OM
authors.lastname: Bautista
authors.forename: Radha A
authors.initials: RA
authors.lastname: Railkar
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Lupinacci
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Insinga
authors.forename: Heather L
authors.initials: HL
authors.lastname: Sings
authors.forename: Richard M
authors.initials: RM
authors.lastname: Haupt
mesh_terms: D000293:Adolescent; D000328:Adult; D052685:Alphapapillomavirus; D002170:Canada; D005260:Female; D005831:Genital Diseases, Female / Q000517:prevention & control* / Q000821:virology*; D000068857:Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18; D006801:Humans; D030361:Papillomavirus Infections / Q000517:prevention & control*; D053918:Papillomavirus Vaccines; D011647:Puerto Rico; D012725:Sexual Behavior; D014481:United States; D014860:Warts / Q000517:prevention & control* / Q000821:virology*
chemical_list: D000068857:Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18; D053918:Papillomavirus Vaccines