While widespread human papillomavirus (HPV) vaccination is likely to reduce the prevalence of vaccine types 16 and 18, it remains unknown whether high-risk nonvaccine genotypes will fill this ecological niche. In Luxembourg where the national vaccination program introduced in 2008 achieved a coverage of approximately 60%, the first cohorts of vaccinated girls are now entering opportunistic cervical cancer screening yielding an opportunity to investigate both hypotheses of vaccine type reduction and nonvaccine genotype replacement.
We extracted HPV test results from a large clinical laboratory in Luxembourg offering HPV genotyping in the context of opportunistic cervical cancer screening. 17901 HPV test results of cervical samples of adult women (mean age 37 y.) during the period January 2010 –June 2017 were assessed in this study. After screening by Hybrid Capture 2 (Qiagen, Germany) assay, positive samples were genotyped using LCD-Array (Chipron, Germany). We compared fractional polynomial prevalence trends of individual 13 high risk HPV (hrHPV) genotypes by logistic regression and the relative contribution of the 13 genotypes over time in young age groups targeted by vaccination (<25 y.) and older untargeted age groups (>=30 y.).
Overall, 3631 samples (20.3%) were positive for hrHPV, including 583 samples (31.8%) in women younger than 25 y. Increasing prevalence over time (p<0.05) were observed for individual genotypes 39, 51, 52 and 59 among women younger than 25 y., but not in women older than 30 y. Among hrHPV positive women younger than 25 y., the relative contribution of vaccine types 16 and 18 dropped from 34% in 2010 to 7% in 2017 (chi2-test, p<0.001). In this age group, the relative contribution of genotypes 39, 51, 52 and 59 increased from 21% in 2010 to 52% in 2017 (chi2-test, p=0.001).
Between 2010 and 2017, a significant change of hrHPV genotype distribution in young women undergoing opportunistic cervical cancer screening occurred in Luxembourg. Whether these changes represent genotype replacement remains unclear. Studies in other settings are warranted to verify our findings. In any case, the clinical impact for screening of nonvaccine high-risk genotypes deserves further investigation.