HPV vaccination programs with the HPV bivalent (HPV16/18) vaccine (Cervarix®, GlaxoSmithKline Biologicals, United Kingdom) or the recombinant HPV quadrivalent (HPV16/18/6/11) vaccine (Gardasil®, Merck & Co, Inc., USA) have been implemented in the majority of industrialized countries. According to the International Agency of Research on Cancer (IARC, World Health Organization, France) HPV67 is subdivided as a possible high-risk HPV. This study was performed to broaden the epidemiological knowledge of HPV67 in a Belgian Routine setting, and to evaluate the potential influence of vaccination status on its prevalence.
In total, 478,822 samples were evaluated with the Riatol qPCR assay. Self-reported vacination status was known for 376,905 samples. A subset of 22,878 women reported to be vaccinated.
HPV67 is found in 1.23% (95% CI: 1.20%-1.26%) of the screening population, with a significant (p<0.001, Pearson's Chi Square Test) higher prevalence in the diagnostic population 4.16% (95% CI: 4.04%-4.28%). In the screening population, multiple infections with other HPV genotype(s) occur in 51.36% (95% CI: 49.96%-52.76%). The most prevalent coinfections involve HPV39/51/16/59. Furthermore, HPV67 is associated with HPV18/39/31 in coinfections within the diagnostic population. HPV67 is significantly (p=0.021, Pearson's Chi Square Test) more prevalent in vaccinated women (3.36%; 95% CI: 3.06%-3.68%), compared to the non-vaccinated population (2.94%; 95% CI: 2.75%-3.14%). Similar results are obtained for other HPV types. In the proportion of women vaccinated with Gardasil® (0.13%; 95% CI: 0.11%-0.14%) vs Cervarix® (0.11%; 95% CI: 0.08%-0.13%) no significant differences (p=0.228, Pearson's Chi Square Test) are found.
The overall prevalence of HPV67 in Belgian women is 1.86%. The changing coinfection patterns between screening and diagnostic populations should be topic of further research. Specific non-HPV16/18 genotypes are observed to be significantly more prevalent in vaccinated women, irrespective of vaccine type. These data hypothesize a continuous HPV genotype shift. In addition, HPV31/33 (together with HPV16 in α9-species) and HPV45/68 (with HPV18 in α7-species) display a significant reduction in prevalence in the vaccinated population. Phylogenetic related HPV genotypes share similar capsid epitopes, potentially eliciting cross-reactive immune responses after vaccination. Our findings indicate that selected possible high-risk HPV types as HPV67 are more frequently found in vaccinated women. It is therefore warranted to perform close surveillance on the transforming potential of these types, including HPV67.