title: Effect of human papillomavirus vaccination on cervical cancer screening in Alberta.
abstract: BACKGROUND
  A school-based program with quadrivalent human papillomavirus (HPV) vaccination was implemented in Alberta in 2008. We assessed the impact of this program on Pap test cytology results using databases of province-wide vaccination and cervical cancer screening.
  
  
  METHODS
  We conducted a nested case-control study involving a cohort of women in Alberta born between 1994 and 1997 who had at least 1 Pap test between 2012 and 2015. Women with negative cytology results were controls. Women with low-grade (atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion) and high-grade (atypical squamous cells, cannot rule out a high-grade lesion; or high-grade squamous intraepithelial lesion) cervical abnormalities were cases. Exposure status was assigned according to records of HPV vaccination. Odds ratios (ORs) for abnormal cytology results by vaccination status were adjusted for neighbourhood income, laboratory service, rural versus urban residency, and age.
  
  
  RESULTS
  The total study population was 10 204. Adjusting for age, vaccinated women had a higher screening rate than unvaccinated women (13.0% v. 11.4%, p < 0.001). Among women who received full vaccination (≥ 3 doses), the adjusted OR for cervical abnormalities was 0.72 (95% confidence interval [CI] 0.63-0.82). For high-grade lesions, the adjusted OR was 0.50 (95% CI 0.30-0.85). With 2-dose HPV vaccination, the adjusted OR for cervical abnormalities was 1.08 (95% CI 0.84-1.38).
  
  
  CONCLUSIONS
  Quadrivalent HPV vaccination significantly reduced high-grade cervical abnormalities but required 3 doses. Vaccination against HPV was associated with screening uptake. Population-based vaccination and screening programs should work together to optimize cervical cancer prevention.
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta.
authors.forename: Jong
authors.initials: J
authors.lastname: Kim
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta.
authors.forename: Christopher
authors.initials: C
authors.lastname: Bell
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta.
authors.forename: Maggie
authors.initials: M
authors.lastname: Sun
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta.
authors.forename: Gordon
authors.initials: G
authors.lastname: Kliewer
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta.
authors.forename: Linan
authors.initials: L
authors.lastname: Xu
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta.
authors.forename: Maria
authors.initials: M
authors.lastname: McInerney
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta.
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Svenson
authors.affiliation: Public Health and Preventive Medicine Residency Program (Kim), Cumming School of Medicine, University of Calgary, Calgary; Surveillance and Assessment Branch (Bell, Svenson), Alberta Health, Edmonton; Screening Programs (Sun, Kliewer, Xu, McInerney, Yang), Alberta Health Services, Calgary; School of Public Health (Svenson), University of Alberta, Edmonton; Department of Community Health Sciences (Svenson), Cumming School of Medicine, University of Calgary, Alta. Huiming.Yang@albertahealthservices.ca.
authors.forename: Huiming
authors.initials: H
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000416:Alberta; D016022:Case-Control Studies; D016208:Databases, Factual; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008403:Mass Screening / Q000706:statistics & numerical data; D065006:Papanicolaou Test; D030361:Papillomavirus Infections / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000627:therapeutic use*; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000821:virology; D014611:Vaccination / Q000706:statistics & numerical data*; D014626:Vaginal Smears; D055815:Young Adult
chemical_list: D053918:Papillomavirus Vaccines