WHO study

Aim: Impact of vaccination against Human Papilloma Virus (HPV) in Rwanda and Bhutan

Partners: WHO-IARC, University of Antwerp (VAXINFECTIO), Novosanis nv

Results have been published in the International Journal of Cancer (2016;139:518-526) by Franceschi S et al.

Two school-based HPV urine surveys were performed as earliest indicators of HPV vaccine effectiveness. 973 female students (median age: 19 years, 5th-95th percentile: 18-22) were recruited in Bhutan and 912 (19 years, 17-20) in Rwanda. Participants self-collected a first-void urine sample using a validated protocol. HPV prevalence was obtained using two PCR assays that differ in sensitivity and type spectrum, namely GP5+/GP6+ and E7-MPG.

Main results included:

• 92% students in Bhutan and 43% in Rwanda reported to have been vaccinated (median vaccination age = 16, 5th-95th: 14-18)
• HPV positivity in urine was significantly associated with sexual activity measures.
• In Rwanda, HPV6/11/16/18 prevalence was lower in vaccinated than in unvaccinated students (prevalence ratio, PR = 0.12, 95% confidence interval, CI: 0.03-0.51 by GP5+/GP6+, and 0.45, CI: 0.23-0.90 by E7-MPG). For E7-MPG, cross-protection against 10 high-risk types phylogenetically related to HPV16 or 18 was of borderline significance (PR = 0.68; 95% CI: 0.45-1.01).
• In Bhutan, HPV6/11/16/18 prevalence by GP5+/GP6+ was lower in vaccinated than in unvaccinated students but CIs were broad.

In conclusion, our study supports the feasibility of urine surveys to monitor HPV vaccination and quantifies the effectiveness of the quadrivalent vaccine in women vaccinated after pre-adolescence. Future similar surveys should detect increases in vaccine effectiveness if vaccination of 12 year-olds continues.