Persistence or clearance of human papillomavirus infections in women in Ouro Preto, Brazil.

Persistent high-risk (HR) human papillomavirus (HPV) infection is necessary for development of precursor lesions and cervical cancer. We investigate persistence and clearance of HPV infections and cofactors in unvaccinated women. Cervical samples of 569 women (18-75 years), received for routine evaluation in the Health Department of Ouro Preto, Brazil, were collected and subjected to PCR (MY09/11 or GP5+/6+ primers), followed by RFLP or sequencing. All women were interviewed to collect sociodemographic and behavioral information. Viral infection persistence or clearance was reevaluated after 24 months and was observed in 59.6% and 40.4% of women, respectively. HPVs 16, 33, 59, 66, 69, and 83 (HR) were the most persistent types whereas HPVs 31, 45, and 58 were less persistent. Clearance or persistence did not differ between groups infected by HPVs 18, 53, and 67. In low-risk (LR) types, HPV 6 infected samples were associated with clearance, while HPV 11, 61, 72, or 81 infected samples were persistent in the follow-up. No statistically significant association was detected between persistent HPV infections and sociodemographic and behavioral characteristics analyzed. To study persistence or clearance in HPV infection allows the identification of risk groups, cofactors, and strategies for prevention of cervical cancer.