Cervical infections by multiple human papillomavirus (HPV) genotypes: prevalence and impact on the risk of precancerous epithelial lesions

A large proportion of human papillomavirus (HPV) infections is sustained by multiple genotypes. The effect of multiple infections on the risk of cervical intraepithelial neoplasia (CIN) and the potential efficacy of vaccine on these infections are controversial. We performed viral typing by SFP10-LIPA on a consecutive series of 1,323 women undergoing colposcopy, 69% of whom had cervical biopsy, and correlated CIN severity with the type and number of HPVs. Overall prevalence of HPV-DNA was 68.9%, 97.3% in CIN1, and 98.1% in CIN_2. HPV positivity correlated with younger age (35.9 vs. 37.3 years, P¼0.026) and history of CIN (P<0.001). Multiple types were detected in 44.2% of cases, including 63.1% CIN1 and 80.8% CIN_2. Twenty-three different types were detected, HPV-16, 31 and 52 being the most frequent. Infections by HPV-6, 11, 16, or 18 occurred in 59.4% of CIN1 and 71.3% of CIN_2. Number of viral types and class of oncogenic risk were linearly correlated with CIN severity (P<0.0001) by univariate and multivariate analyses controlling for age and history of CIN. The effect of the number of HPV types was maintained after exclusion from the model of infections by HPV-6, 11, 16, and 18. Frequency, distribution, and clinical correlates of multiple HPV infections highlight the importance of assessing individual types in the management and the prediction of outcome of women with abnormal baseline cytology and point to potential limitations in current vaccine strategies.