High-risk HPV infection after five years in a population-based cohort of Chilean women

A population-based random sample of 969 women from Santiago, Chile aged 17 years or older was enrolled in 2001 and revisited in 2006. At both visits they answered a survey on demographics and sexual history and provided a cervical sample for HPV DNA detection (GP5+/6+ primer-mediated PCR and Reverse line blot genotyping). Follow-up was completed by 576 (59.4%) women; 45 (4.6%) refused participation; most losses to follow-up were women who were unreachable, no longer eligible or had missing samples. HR-HPV prevalence increased by 43%. Incidence was highest in women < 20 years of age (19.4%) and lowest in women > 70 (0%); it was three times higher among women HR-HPV positive versus HPV negative at baseline (25.5% and 8.3%; OR 3.8, 95% CI 1.8-8.0). Type-specific persistence was 35.3%; it increased with age, from 0% in women < 30 years of age to 100% in women > 70. An enrollment Pap result ASCUS or worse was the only risk factor for being HR-HPV positive at both visits.HR-HPV prevalence increased in the study population. All HR-HPV infections in women < 30 years old cleared, supporting the current recommendation of HR-HPV screening for women > 30 years.Most research on the natural history of human papillomavirus (HPV) infection and its progression towards cancer has been conducted in developed areas. In Chile, a middle developing country, the only two population-based studies to date analyzed the prevalence of HPV at one point in time [1,2]. Chile has a well-organized nationwide cervical cancer prevention program based on Papanicolaou screening, which, after an initial impact on cervical cancer mortality, has not produced a significant decrease in the last decade [3]. Moreover, Chile currently has a high socioeconomic status differential in cervical cancer mortality (C. Ferreccio, unpublished observations). The need to review prevention programs has been triggered by the availability of two new effective prevention tools linked to HPV: vaccines and screening tests. To c