Single and multiple human papillomavirus infections in cervical abnormalities in Portuguese women.

Persistent infection with high-risk (HR) human papillomavirus (HPV) types is necessary for cervical cancer development. However, little is known about the influence of multiple HPV infections on cervical lesion risk. The aim of this study was to evaluate the frequency of single and multiple HPV infections in Portuguese women, and to assess the frequency of multiple infections in cervical intraepithelial neoplasia (CIN). HPV prevalence, type-specific prevalence and extent of multiple infections were assessed in 1057 cervical samples. The Clinical Array HPV assay was used to detect 35 HPV types. According to histological diagnosis, 425 samples were normal, 375 were CIN1, and 257 were CIN2+. HPV status was studied in relation to age and lesion severity. The prevalence of HPV infection was 52.7%; 25.4%, 67.2% and 76.7% were positive for any HPV type in the normal, CIN1 and CIN2+ cases, respectively. Among HPV-positive cases, 32.0% were associated with multiple infections. Among multiple infections, 96.1% harboured HR HPV types and 38.2% HR-low risk (LR) HPV types. Overall, 33 different HPV types (18 HR and 15 LR) were detected. HR HPV types (44.1%) were significantly more prevalent than LR HPV types (8.6%). The most frequent genotype was HPV 16 (25.5%), followed by HPV 31, 53, 66, 58, and 51. Multiple infections showed a significant increase (p 0.005) according to severity of neoplasia, particularly for HR-HR HPV infections (p 0.003). No association between age and multiple HPV infections was observed (p 0.812). However, multiple HR HPV infections were more frequent in women under 30 years of age (35.3%).