title: Effectiveness of human papillomavirus vaccine against incident and persistent infections among young girls: Results from a longitudinal Dutch cohort study.
abstract: BACKGROUND
  Because of the long interval between infection with high-risk human papillomavirus (hrHPV) and development of cervical cancer surrogate markers for cancer incidence are necessary to monitor vaccine effectiveness (VE). The aim of this study was to calculate VE of HPV16/18 vaccination by annually assessing incident and persistent infections among (un)vaccinated girls from the general Dutch population up to 3 years after vaccination.
  
  
  METHODS
  In 2009, 1668 girls (54% vaccinated) aged 14-16 years were enrolled in a prospective cohort study. Annually, questionnaire data were obtained, and a vaginal swab was tested for type-specific HPV DNA with SPF10-LiPA. VE was estimated by a Poisson model comparing type-specific infection rates in (un)vaccinated girls.
  
  
  RESULTS
  The adjusted VE (95% CI) was 73% (49-86%) against incident infections with HPV16/18 and 72% (52-84%) against HPV16/18/31/45. VE against persistent HPV16/18 was 100% and 76% (-17 to 95%) against HPV16/18/31/45. This number was lower (36%) when girls who were positive for HPV16 and 18 at baseline were included in the analysis. The overall VE for hrHPV types combined was small. Although 96% of girls were HPV-naïve at baseline, the cumulative 36-month incidence for any HPV was 20%, indicating high sexual activity.
  
  
  CONCLUSIONS
  Vaccination is effective against incident and persistent infections with HPV16/18 and HPV16/18/31/45. Low VE against persistent HPV16/18 infection in girls positive at baseline indicates importance of vaccination before sexual debut.
authors.affiliation: Department of Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands; Department of Pathology, VU University Medical Centre (VUmc), Amsterdam, The Netherlands.
authors.forename: Madelief
authors.initials: M
authors.lastname: Mollers
authors.affiliation: Laboratory For Infectious Diseases and Screening, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Audrey J
authors.initials: AJ
authors.lastname: King
authors.affiliation: Department of Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Mirjam J
authors.initials: MJ
authors.lastname: Knol
authors.affiliation: Department of Pathology, VU University Medical Centre (VUmc), Amsterdam, The Netherlands; Laboratory For Infectious Diseases and Screening, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Mirte
authors.initials: M
authors.lastname: Scherpenisse
authors.affiliation: Department of Pathology, VU University Medical Centre (VUmc), Amsterdam, The Netherlands.
authors.forename: Chris J L M
authors.initials: CJ
authors.lastname: Meijer
authors.affiliation: Laboratory For Infectious Diseases and Screening, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Fiona R M
authors.initials: FR
authors.lastname: van der Klis
authors.affiliation: Department of Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands. Electronic address: Hester.de.Melker@rivm.nl.
authors.forename: Hester E
authors.initials: HE
authors.lastname: de Melker
mesh_terms: D000293:Adolescent; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D009426:Netherlands / Q000453:epidemiology; D030361:Papillomavirus Infections / Q000453:epidemiology / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014621:Vagina / Q000821:virology
chemical_list: D053918:Papillomavirus Vaccines
keywords: Cervical cancer; HPV; Impact; Monitoring; Vaccination