Human papillomavirus infection in Bhutan at the moment of implementation of a national HPV vaccination programme

BACKGROUND: Cervical cancer is the most common female cancer in Bhutan, the first low/middle-income country to implement a national human papillomavirus (HPV) vaccination programme. METHODS: To provide a robust baseline for future evaluations of vaccine effectiveness, cervical cell specimens were obtained from 2,505 women aged 18–69 years from the general population, and biopsies from 211 cervical intraepithelial neoplasia grade 3 (CIN3) and 112 invasive cervical cancer (ICC) cases. Samples were tested for HPV using GP5+/6+ PCR. RESULTS: Among the general population, HPV prevalence was 26%, being highest (33%) in women ≤24 years, but remaining above 15% in all age-groups. Determinants of HPV included age, marital status, and number of sexual partners. Among the eight percent with cytological abnormalities, 24 CIN3 and 4 ICC were histologically confirmed. Even after additional testing with a sensitive E7 PCR, no infections with vaccine-targeted HPV types were detected in the few vaccinated women (n = 34) compared to 6% prevalence in unvaccinated women of similar age (p = 0 · 215). CONCLUSION: Based upon type-specific prevalence among biopsies, at least 70% of ICC in Bhutan are theoretically preventable by HPV16/18 vaccination, but screening programmes should be expanded among older women, who have an important underlying burden of CIN3 and ICC

Evaluation of the performance of Human Papillomavirus testing in paired urine and clinician-collected cervical samples among women aged over 30 years in Bhutan

Abstract Background Urine sampling may offer a less invasive solution than cervical sampling to test for human papillomavirus (HPV) for HPV vaccine impact monitoring. Methods Paired samples of urine and exfoliated cervical cells were obtained for 89 women with history of high-risk (HR) HPV-positive normal cytology in Bhutan. Urine sampling protocol included self-collection of first-void urine immediately into a conservation medium and procedures to optimize DNA yield. Colposcopical abnormalities were biopsied. Two HPV assays were used: a multiplex type-specific PCR (E7-MPG) and a less analytically sensitive GP5+/6+ PCR followed by reverse line blot. Results HPV positivity for 21 types common to both assays was similar in urine and cells by E7-MPG (62.9% and 57.3%, respectively, p = 0.32) but lower in urine by GP5+/6+ (30.3% and 40.4%, p = 0.05). HPV6/11/16/18 positivity did not significantly differ between urine and cells by either assay. Sensitivity of urine (using cells as gold standard) to detect 21 HPV types was 80% and 58% for E7-MPG and GP5+/6+, respectively, with specificity 61% and 89%. HPV type distribution in urine and cells was similar, regardless of assay. The 5 detected CIN3+ were HR-HPV positive in cells by both assays, compared to 4 and 3 by E7-MPG and GP5+/6+, respectively, in urine samples. Conclusion For the monitoring of vaccine impact, we demonstrate validity of a urine sampling protocol to obtain HPV prevalence data that are broadly comparable to that from cervical cells. However, detection of HPV in urine varies according to assay sensitivity, presumably because low level infections are frequent