Leah M Smith1, Erin C Strumpf2, Jay S Kaufman3, Aisha Lofters4, Michael Schwandt5, Linda E Lévesque6. 1. Departments of Epidemiology, Biostatistics, and Occupational Health, and leahmariesmith@gmail.ca. 2. Departments of Epidemiology, Biostatistics, and Occupational Health, and Economics, McGill University, Montreal, Quebec, Canada; 3. Departments of Epidemiology, Biostatistics, and Occupational Health, and. 4. Department of Family and Community Medicine, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; 5. Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; 6. Department of Public Health Sciences, Queen's University, Kingston, Ontario, Canada; and Institute for Clinical Evaluative Sciences-Queen's Health Services Research Facility, Kingston, Ontario, Canada.
Abstract
BACKGROUND: Despite widespread promotion of quadrivalent human papillomavirus (qHPV) vaccination for young girls, there is limited information on the vaccine's real-world effectiveness and none on the effectiveness of qHPV vaccination programs. We assessed the impact of the qHPV vaccine and Ontario's grade 8 qHPV vaccination program on cervical dysplasia and anogenital warts (AGW). METHODS: By using administrative health databases of Ontario, Canada, we identified a population-based retrospective cohort of girls in grade 8 before (2005/2006-2006/2007) and after (2007/2008-2008/2009) program implementation. Vaccine exposure was ascertained in grades 8 to 9 and outcomes in grades 10 to 12. A quasi-experimental approach known as regression discontinuity was used to estimate absolute risk differences (RDs), relative risks (RRs), and 95% confidence intervals (CIs) attributable to vaccination and program eligibility (intention-to-treat analysis). RESULTS: The cohort comprised 131,781 ineligible and 128,712 eligible girls (n = 260,493). We identified 2436 cases of dysplasia and 400 cases of AGW. Vaccination significantly reduced the incidence of dysplasia by 5.70 per 1000 girls (95% CI -9.91 to -1.50), corresponding to a relative reduction of 44% (RR 0.56; 95% CI 0.36 to 0.87). Program eligibility also had a significant protective effect on dysplasia: RD -2.32/1000 (95% CI -4.02 to -0.61); RR 0.79 (95% CI 0.66 to 0.94). Results suggested decreases in AGW attributable to vaccination (RD -0.83/1000, 95% CI -2.54 to 0.88; RR 0.57, 95% CI 0.20 to 1.58) and program eligibility (RD -0.34/1000, 95% CI -1.03 to 0.36; RR 0.81, 95% CI 0.52 to 1.25). CONCLUSIONS: This study provides strong evidence of the early benefits of qHPV vaccination among girls aged 14 to 17 years, offering additional justification for not delaying vaccination.
BACKGROUND: Despite widespread promotion of quadrivalent human papillomavirus (qHPV) vaccination for young girls, there is limited information on the vaccine's real-world effectiveness and none on the effectiveness of qHPV vaccination programs. We assessed the impact of the qHPV vaccine and Ontario's grade 8 qHPV vaccination program on cervical dysplasia and anogenital warts (AGW). METHODS: By using administrative health databases of Ontario, Canada, we identified a population-based retrospective cohort of girls in grade 8 before (2005/2006-2006/2007) and after (2007/2008-2008/2009) program implementation. Vaccine exposure was ascertained in grades 8 to 9 and outcomes in grades 10 to 12. A quasi-experimental approach known as regression discontinuity was used to estimate absolute risk differences (RDs), relative risks (RRs), and 95% confidence intervals (CIs) attributable to vaccination and program eligibility (intention-to-treat analysis). RESULTS: The cohort comprised 131,781 ineligible and 128,712 eligible girls (n = 260,493). We identified 2436 cases of dysplasia and 400 cases of AGW. Vaccination significantly reduced the incidence of dysplasia by 5.70 per 1000 girls (95% CI -9.91 to -1.50), corresponding to a relative reduction of 44% (RR 0.56; 95% CI 0.36 to 0.87). Program eligibility also had a significant protective effect on dysplasia: RD -2.32/1000 (95% CI -4.02 to -0.61); RR 0.79 (95% CI 0.66 to 0.94). Results suggested decreases in AGW attributable to vaccination (RD -0.83/1000, 95% CI -2.54 to 0.88; RR 0.57, 95% CI 0.20 to 1.58) and program eligibility (RD -0.34/1000, 95% CI -1.03 to 0.36; RR 0.81, 95% CI 0.52 to 1.25). CONCLUSIONS: This study provides strong evidence of the early benefits of qHPV vaccination among girls aged 14 to 17 years, offering additional justification for not delaying vaccination.
Authors: Nicolas F Schlecht; Angela Diaz; Viswanathan Shankar; Arnold H Szporn; Maoxin Wu; Anne Nucci-Sack; Ken Peake; Howard D Strickler; Robert D Burk Journal: J Infect Dis Date: 2016-10-12 Impact factor: 5.226
Authors: Darren R Brenner; Yibing Ruan; Eileen Shaw; Dylan O'Sullivan; Abbey E Poirier; Emily Heer; Paul J Villeneuve; Stephen D Walter; Christine M Friedenreich; Leah Smith; Prithwish De Journal: CMAJ Date: 2019-11-18 Impact factor: 8.262
Authors: Erin Y Liu; Leah M Smith; Anne K Ellis; Heather Whitaker; Barbara Law; Jeffrey C Kwong; Paddy Farrington; Linda E Lévesque Journal: CMAJ Date: 2018-05-28 Impact factor: 8.262
Authors: Jong Kim; Christopher Bell; Maggie Sun; Gordon Kliewer; Linan Xu; Maria McInerney; Lawrence W Svenson; Huiming Yang Journal: CMAJ Date: 2016-07-04 Impact factor: 8.262
Authors: Catherine E Oldenburg; N Venkatesh Prajna; Tiruvengada Krishnan; Revathi Rajaraman; Muthiah Srinivasan; Kathryn J Ray; Kieran S O'Brien; M Maria Glymour; Travis C Porco; Nisha R Acharya; Jennifer Rose-Nussbaumer; Thomas M Lietman Journal: Ophthalmic Epidemiol Date: 2018-05-02 Impact factor: 1.648
Authors: Erika L Thompson; Ellen M Daley; Tricia Washburn; Kim Salisbury-Keith; Debbie Saslow; Holly B Fontenot; Gregory D Zimet Journal: Hum Vaccin Immunother Date: 2020-12-17 Impact factor: 3.452