Monitoring vaccine and non-vaccine HPV type prevalence in the post-vaccination era in women living in the Basilicata region, Italy

Abstract

BackgroundA large free-of-charge quadrivalent HPV (qHPV) vaccination program, covering four cohorts annually (women 11, 14, 17 and 24 years), has been implemented in Basilicata since 2007. This study evaluated vaccine and non-vaccine HPV prevalence 5-7 years post-vaccination program implementation in vaccinated and unvaccinated women.MethodsThis population-based, cross-sectional study was conducted in the public screening centers of the Local Health Unit in Matera between 2012 and 2014. Cervical samples were obtained for Pap and HPV testing (HC2, LiPA Extra® assay) and participants completed a sociodemographic and behavioral questionnaire. Detailed HPV vaccination status was retrieved from the official HPV vaccine registry. HPV prevalence was described overall, by type and vaccination status. The association between HPV type-detection and risk/protective factors was studied. Direct vaccine protection (qHPV vaccine effectiveness [VE]), cross-protection, and type-replacement were evaluated in cohorts eligible for vaccination, by analyzing HPV prevalence of vaccine and non-vaccine types according to vaccination status.ResultsOverall, 2793 women (18-50 years) were included, 1314 of them having been in birth cohorts eligible for the HPV vaccination program (18- to 30-year-old women at enrolment). Among the latter, qHPV vaccine uptake was 59% (at least one dose), with 94% completing the schedule; standardized qHPV type prevalence was 0.6% in vaccinated versus 5.5% in unvaccinated women (P <0.001); adjusted VE against vaccine type infections was 90% (95% CI: 73%-96%) for all fully vaccinated women and 100% (95% CI not calculable) in women vaccinated before sexual debut. No statistically significant difference in overall high-risk HPV, high-risk non-vaccine HPV, or any single non-vaccine type prevalence was observed between vaccinated and unvaccinated women.ConclusionsThese results, conducted in a post-vaccine era, suggest a high qHPV VE and that a well-implemented catch-up vaccination program may be efficient in reducing vaccine-type infections in a real-world setting. No cross-protective effect or evidence of type-replacement was observed a few years after HPV vaccine introduction.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-2945-8) contains supplementary material, which is available to authorized users.

Prevalence of Vaccine Type Infections in Vaccinated and Non-Vaccinated Young Women: HPV-IMPACT, a Self-Sampling Study

“…We found a statistically significant difference in the prevalence of high-risk genotypes (6/11/16 and 18) between vaccinated and unvaccinated young women. These findings confirm the results of other studies on the effectiveness of the HPV vaccination as a means to decrease the prevalence of vaccine-targeted HPV types [ 13 , 14 , 15 , 16 ]. On the other hand, we observed no cross-protection for the other HPV genotypes, as we found no significant difference in the prevalence of non-Gardasil targeted genotypes between vaccinated and unvaccinated women, similar to other studies on the subject [ 17 , 18 ].…”

Cervicovaginal Fungi and Bacteria Associated With Cervical Intraepithelial Neoplasia and High-Risk Human Papillomavirus Infections in a Hispanic Population

“…Other methods maybe be less sensitive, consistent with the lower prevalences reported for Latin America and Caribbean region in high-grade squamous intraepithelial lesions (41–67%) ( Parkin et al, 2008 ). High HPV prevalence ranging from 30 to 50% have been reported for other high-risk Latin American countries, using the same genotyping method SPF 25 /LiPA 10 , including anal specimens in Costa Rica ( Castro et al, 2012 ), and vaginal specimens in Surinam ( Geraets et al, 2014 ), as well as for Nigeria ( Adebamowo et al, 2017 ), Turkey ( Barut et al, 2018 ), and Italy ( Carozzi et al, 2018 ). The very high prevalence found in our study may reflect the high-risk patients from the San Juan Municipality, known to have rising cervical cancer diagnoses ( Registro Central De Cáncer De Puerto Rico, 2017 ).…”

Evidence for cross-protection but not type-replacement over the 11 years after human papillomavirus vaccine introduction

“…26 Carozzi et al found no statistically significant differences in nonvaccine-type HPV in unvaccinated vs. vaccinated women after vaccine introduction in Italy, suggesting no evidence of type replacement. 25 In contrast, among a sample of 3,183 Finnish women, Merikukka et al demonstrated a possible competitive advantage for HPV33 over other genital HPV types in the unvaccinated population, and suggested that HPV33 should be monitored for type replacement after widespread HPV vaccination. 19 Table 3.…”

“…Other studies have similarly found no conclusive evidence of type replacement in realworld settings, but some have identified signals that confirm the importance of continued surveillance. [18][19][20][21]25,26 Yang et al examined concurrence of multiple HPV infections in 47,617 women undergoing cervical cancer screening, and found a negative interaction between HPV16 and other HPV types among women with abnormal cytology, but not among those with normal cytology, suggesting that type replacement in vaccinated women is unlikely in the general population. 21 Tota et al compared acquisition and clearance of 30 HPV types, using data from three studies involving 3200 women.…”