Carrie Rh Innes1, Jonathan A Williman2, Bryony J Simcock3, Phil Hider4, Margaret Sage5, Kieran Dempster-Rivett6, Beverley A Lawton7, Peter H Sykes3. 1. Department of Obstetrics and Gynaecology, University of Otago, Christchurch. 2. Biostatistics and Computational Biology Unit, University of Otago, Christchurch. 3. Department of Obstetrics and Gynaecology, University of Otago, Christchurch; Christchurch Women's Hospital, Christchurch. 4. Department of Population Health, University of Otago, Christchurch. 5. National Cervical Screening Programme, Wellington. 6. Middlemore Hospital, Auckland. 7. Centre for Women's Health Research, Victoria University of Wellington, Wellington.
Abstract
AIM: Determine the impact of quadrivalent human papillomavirus (HPV) vaccination on abnormal cervical cytology and histology rates in young New Zealand women. METHODS: Retrospective population-based cohort study of women born 1990-1994, with a cervical cytology or histology recorded when aged 20-24 between 1 January 2010 and 31 December 2015. Data was obtained through linking the National Immunisation Register and National Cervical Screening Programme Register. RESULTS: N=104,313 women (376,402 person years of follow up) were included. The incidence of high-grade cytology was lower in vaccinated women (at least one dose prior to 18 years) than in unvaccinated women (8.5 vs 11.3 per 1,000 person years [p1000py], incidence rate ratio [IRR 0.75], 95% CI 0.70, 0.80, p<.001). The incidence of high-grade histology was lower in vaccinated women than in unvaccinated women (6.0 vs 8.7 p1000py, IRR 0.69, 95% CI 0.64, 0.75, p<.001). There was no evidence of a difference in the incidence of high-grade histology between European and Māori women overall or after taking vaccination status into account. CONCLUSIONS: Receiving at least one dose of quadrivalent HPV vaccine prior to 18 years was associated with a 25% lower incidence of high-grade cytology and 31% lower incidence of high-grade histology in women aged 20-24 years.
AIM: Determine the impact of quadrivalent human papillomavirus (HPV) vaccination on abnormal cervical cytology and histology rates in young New Zealand women. METHODS: Retrospective population-based cohort study of women born 1990-1994, with a cervical cytology or histology recorded when aged 20-24 between 1 January 2010 and 31 December 2015. Data was obtained through linking the National Immunisation Register and National Cervical Screening Programme Register. RESULTS: N=104,313 women (376,402 person years of follow up) were included. The incidence of high-grade cytology was lower in vaccinated women (at least one dose prior to 18 years) than in unvaccinated women (8.5 vs 11.3 per 1,000 person years [p1000py], incidence rate ratio [IRR 0.75], 95% CI 0.70, 0.80, p<.001). The incidence of high-grade histology was lower in vaccinated women than in unvaccinated women (6.0 vs 8.7 p1000py, IRR 0.69, 95% CI 0.64, 0.75, p<.001). There was no evidence of a difference in the incidence of high-grade histology between European and Māori women overall or after taking vaccination status into account. CONCLUSIONS: Receiving at least one dose of quadrivalent HPV vaccine prior to 18 years was associated with a 25% lower incidence of high-grade cytology and 31% lower incidence of high-grade histology in women aged 20-24 years.