Prevalence of High-Risk Human Papillomaviruses (HPV) in Slovenian Women Attending Organized National Cervical Cancer Screening 14 Years After Implementation of the National HPV Vaccination Program.

Background/Objectives: To assess overall and type-specific HPV vaccine effectiveness in central and eastern Europe (CEE), the age-stratified prevalence of cervical HPV infection was determined among Slovenian women aged 20 to 64 attending a cervical cancer screening program 14 years after implementation of a national HPV vaccination program, which was then compared with 2009-2010 pre-vaccination data using the same methodological approach. Methods: Cervical samples of 4419 women were tested in 2023-2025 using the clinically validated Alinity m HR HPV Assay, and individual HPV types were determined by the Allplex HPV HR Detection assay. Results were compared with 2009-2010 pre-vaccination data generated using the same assay on an age-range matched cohort of women. Results: The overall prevalence of the 14 Alinity-targeted HPV types was 10.0% in 2023-2025 versus 13.3% in 2009-2010 (p < 0.001). HPV16 prevalence declined from 3.5% to 1.5% (p < 0.001), and HPV18 prevalence from 1.1% to 0.5% (p = 0.005). In women aged 20 to 24 with 40% uptake of quadrivalent HPV vaccine, overall HPV prevalence dropped from 25.3% to 12.8% (p < 0.001). No single case of HPV16/HPV18 infection was detected among vaccinated women. Conclusions: The first large-scale, systematic, and methodologically consistent study of HPV vaccine effectiveness in CEE showed a substantial reduction in high-risk HPV prevalence after implementation of the national program, with the greatest decline among women aged 20 to 24, who harbored the highest HPV burden in the pre-vaccination era. These locally acquired data will considerably inform public health strategies on cervical cancer elimination in CEE.