title: Reduced prevalence of vulvar HPV16/18 infection among women who received the HPV16/18 bivalent vaccine: a nested analysis within the Costa Rica Vaccine Trial.
abstract: BACKGROUND
  Vaccine efficacy (VE) against vulvar human papillomavirus (HPV) infection has not been reported and data regarding its epidemiology are sparse.
  
  
  METHODS
  Women (n = 5404) age 22-29 present at the 4-year study visit of the Costa Rica Vaccine Trial provided vulvar and cervical samples. A subset (n = 1044) was tested for HPV DNA (SPF10/LiPA25 version 1). VE against 1-time detection of vulvar HPV16/18 among HPV vaccinated versus unvaccinated women was calculated and compared to the cervix. Prevalence of and risk factors for HPV were evaluated in the control arm (n = 536).
  
  
  RESULTS
  Vulvar HPV16/18 VE (54.1%; 95% confidence interval [CI], 4.9%-79.1%) was comparable to cervix (45.8%; 95% CI, 6.4%-69.4%). Vulvar and cervical HPV16 prevalence within the control arm was 3.0% and 4.7%, respectively. Independent risk factors for vulvar HPV were similar to cervix and included: age (adjusted odds ratio [aOR] 0.5 [95% CI, .3-.9] ≥28 vs 22-23]); marital status (aOR 2.3 [95% CI, 1.5-3.5] single vs married/living-as-married); and number of sexual partners (aOR 3.6 [95% CI, 1.9-7.0] ≥6 vs 1).
  
  
  CONCLUSIONS
  In this intention-to-treat analysis, VE against vulvar and cervical HPV16/18 were comparable 4 years following vaccination. Risk factors for HPV were similar by anatomic site.
  
  
  BACKGROUND
  NCT00128661.
authors: National Cancer Institute, NIH, Bethesda, Maryland.
authors: Krystle A
authors: KA
authors: Lang Kuhs
authors: Proyecto Epidemiológico Guanacaste, Fundación INCIENSA, Costa Rica Prevention and Implementation Group, International Agency for Research on Cancer, Lyon, France.
authors: Paula
authors: P
authors: Gonzalez
authors: Proyecto Epidemiológico Guanacaste, Fundación INCIENSA, Costa Rica.
authors: Ana Cecilia
authors: AC
authors: Rodriguez
authors: DDL Diagnostic Laboratory, Rijswijk, The Netherlands.
authors: Leen-Jan
authors: LJ
authors: van Doorn
authors: National Cancer Institute, NIH, Bethesda, Maryland.
authors: Mark
authors: M
authors: Schiffman
authors: DDL Diagnostic Laboratory, Rijswijk, The Netherlands.
authors: Linda
authors: L
authors: Struijk
authors: Information Management Services, Calverton, Maryland.
authors: Sabrina
authors: S
authors: Chen
authors: DDL Diagnostic Laboratory, Rijswijk, The Netherlands.
authors: Wim
authors: W
authors: Quint
authors: National Cancer Institute, NIH, Bethesda, Maryland.
authors: Douglas R
authors: DR
authors: Lowy
authors: Proyecto Epidemiológico Guanacaste, Fundación INCIENSA, Costa Rica.
authors: Carolina
authors: C
authors: Porras
authors: Information Management Services, Calverton, Maryland.
authors: Corey
authors: C
authors: DelVecchio
authors: Proyecto Epidemiológico Guanacaste, Fundación INCIENSA, Costa Rica.
authors: Silvia
authors: S
authors: Jimenez
authors: National Cancer Institute, NIH, Bethesda, Maryland.
authors: Mahboobeh
authors: M
authors: Safaeian
authors: National Cancer Institute, NIH, Bethesda, Maryland.
authors: John T
authors: JT
authors: Schiller
authors: National Cancer Institute, NIH, Bethesda, Maryland.
authors: Sholom
authors: S
authors: Wacholder
authors: Prevention and Implementation Group, International Agency for Research on Cancer, Lyon, France.
authors: Rolando
authors: R
authors: Herrero
authors: National Cancer Institute, NIH, Bethesda, Maryland.
authors: Allan
authors: A
authors: Hildesheim
authors: Aimée R
authors: AR
authors: Kreimer
mesh_terms: D000293:Adolescent; D000328:Adult; D002584:Cervix Uteri / Q000821:virology; D003364:Costa Rica / Q000453:epidemiology; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D052162:Human papillomavirus 16 / Q000302:isolation & purification*; D052161:Human papillomavirus 18 / Q000302:isolation & purification*; D006801:Humans; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D015995:Prevalence; D012307:Risk Factors; D014844:Vulva / Q000821:virology; D014845:Vulvar Diseases / Q000453:epidemiology* / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D004279:DNA, Viral; D053918:Papillomavirus Vaccines
keywords: Costa Rica; HPV; HPV vaccine; vulvar human papillomavirus vaccine