Introduction/Background*In 2007, human papillomavirus (HPV) vaccination was rolled out in Australia, with a high uptake of 73% and a consequent reduction in the prevalence of high-grade dysplasia, external genital warts, and HPV 16 and 18 infection in young women. In 2017, the new National Cervical Screening Program (NCSP) was introduced in Australia, which included a later age of entry into screening of 25 years as opposed to 18. This was in light of an improved understanding of the natural history of HPV infection in young women and in line with international guidelines.

This study aims to provide descriptive data on post-vaccination young women aged below 25 years, prior to the change in cervical screening guidelines.

Methodology A retrospective cohort analysis of women under 25 attending our colposcopy service was conducted. Data was extracted from On-Dysplay, a computerised data entry program used for prospective record keeping in our service. Information regarding patient characteristics, HPV vaccination status, referral cytology, colposcopic findings, histological results and treatment outcomes was obtained. Odds ratios (OR) were calculated using MedCalc.

Result(s)*3128 women with a median age of 22 (range 14-24) years were identified. When comparing overall worst histology result, vaccinated women were less likely to have a high grade abnormality than unvaccinated women (RR 0.78, 95%CI 0.67-0.90, p=0.0006). Amongst those with high grade abnormalities, there was no significant difference in rates of CIN2 or CIN3 between vaccinated and unvaccinated women (RR 0.81, 95%CI 0.62-1.05, p=0.1086).

Conclusion*This study provides baseline data on young women under the previous cervical screening program, following the introduction of the HPV vaccine.