A Review of the Impact and Effectiveness of the Quadrivalent Human Papillomavirus Vaccine: 10 Years of Clinical Experience in Canada.

Publicly funded administration of the quadrivalent HPV (qHPV) vaccine in school-aged girls was implemented for all Canadian provinces and territories between 2007 and 2009. However, the impact of female qHPV vaccination in Canada has yet to be evaluated. This systematic literature review of studies published between September 1, 2006 and September 1, 2016 looked at real-world evidence related to the effects of qHPV vaccination on prevalence of HPV infection and disease in Canada over the past decade. PubMed was searched for studies published between September 1, 2006 and September 1, 2016. Studies were eligible if one or more of the following outcomes were assessed in individuals receiving the qHPV vaccine though public immunization programs: HPV infection, anogenital warts (AGW), HPV-associated lesions of the anogenital tract. A "pre-public vaccination program" or "unvaccinated" reference group was required. Key HPV conference abstracts were also reviewed. We identified seven eligible studies representing five Canadian provinces. Results reported indicated that the prevalence of HPV types 6, 11, 16, and 18 was lower in qHPV-vaccinated than unvaccinated individuals (1.5% vs. 11.0%, respectively), whereas non-vaccine-covered genotypes were comparable across vaccination status. Risk of AGW incidence decreased by up to 45% in vaccinated cohorts; incidence of cervical intraepithelial neoplasia 2 + was significantly reduced by up to 86% in the post-vaccine era. On the basis of these findings, HPV vaccination programs constitute a successful and effective public health initiative.

Recurrence of Human Papillomavirus External Genital Wart Infection Among High-Risk Adults in Montréal, Canada.

OBJECTIVES: The incidence of recurrent genital warts is not well characterized; this is especially true in a post-human papillomavirus (HPV) vaccination era. The objectives of this study were to assess the incidence of subsequent HPV-related external genital warts (EGW) episodes in high-risk male and female adults, as well as ascertain patient profile and disease characteristics, in a real-world Canadian sexual health clinical setting. METHODS: Retrospective chart review study conducted at Clinique médicale l'Actuel, a sexual health clinic in Montréal, Québec, Canada. Eligible patients were 18 to 45 years of age with a first diagnosis of EGW associated with a HPV infection between July 1, 2006, and June 30, 2012. RESULTS: A total of 400 first-episode EGW cases were identified. Up to 6 subsequent episodes were documented, with 194 (48.5%) patients reporting at least 1 subsequent EGW episode. Median time to first subsequent EGW episode was 3.97 years, and the incidence density rate for all subsequent episodes was 0.18/100 patient-years. Over 90% of patients reported clearance of the first subsequent episode, with median time to clearance of 0.30 years. Regardless of subsequent episode number, greater than 95% of patients received treatment, primarily cryotherapy, with high-risk sexual behavior reducing as number of episodes increased. CONCLUSIONS: Overall, a high rate of subsequent EGW episodes was observed in this high-risk population, despite high treatment rates and improvement in high-risk sexual behavior. These data, assessed in a prevaccination Québec health care system, may be compared with future EGW rates to assess the impact of a governmentally-funded HPV vaccination program.