Type-specific persistence of high-risk human papillomavirus infections in the new independent states of the former soviet union cohort study

Background: Prospective follow-up studies have recently suggested that persistent high-risk human papillomavirus (HPV) infections play a key role in the progression of CIN lesions and in the development of cervical cancer. However, data on type-specific persistence, viral integration, and the role of multiple infections are scanty. Materials and Methods: A cross-sectional/cohort study was conducted between 1998 and 2002 in three New Independent States of the former Soviet Union comprising a cohort of 3,187 women, of whom 854 women were followed up for a mean of 17 months (SD, 11.6). HPV genotyping was done with real-time PCR, detecting HPV types 16, 18/45, 31, 33/52/ 58, 35, and 39. The integration status of HPV16 was examined by using a novel Taqman-based PCR method. Results: The mean clearance time for the individual high-risk-type infection was 16.5 months (range = 0.9-34.9 months). HPV16 and HPV31 were the most persistent infections (clearance times = 18.1 and 16.2 months, respectively), whereas HPV39 infections cleared most rapidly. The mean copies per cell in HPV18/45, HPV31, HPV33/52/58, and HPV39 infections were higher in persisting HPV infections than in HPV infections that cleared, but the difference was not significant. Integration of HPV16 was not found to correlate with HPV persistence. Conclusions: A large proportion of women remained high-risk HPV positive after 18 months. Coinfection with multiple HPV types, viral load, or integration status did not correlate with persistence of high-risk HPV infections.