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

BACKGROUND: The need to review cervical cancer prevention strategies has been triggered by the availability of new prevention tools linked to human papillomavirus (HPV): vaccines and screening tests. To consider these innovations, information on HPV type distribution and natural history is necessary. This is a five-year follow-up study of gynecological high-risk (HR) HPV infection among a Chilean population-based cohort of women. FINDINGS: 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. CONCLUSIONS: 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.