Natural History of Multiple Human Papillomavirus Infections in Female Adolescents With Prolonged Follow-up

Abstract

The aim of the study was to better characterize the natural history of human papillomavirus (HPV) infections in female adolescents. Female adolescents were enrolled in a longitudinal study. Self-vaginal samples were obtained every 3 months and tested for HPV. No participants received HPV vaccination. The findings for 40 female adolescents with the longest follow-up are reported in this study. Average age at the time of enrollment was 15.2 years (range: 14-17; SD: .97). Mean duration of follow-up was 6.7 years (range: 4.4-9.2; SD: 1.2). In all, 32 participants (80%) reported being involved in sexual activity before their enrollment in the study; all reported being involved in sexual activity before enrollment; all reported being involved in sexual activity during follow-up. Baseline and cumulative prevalence of HPV among participants was 55% and 100%, respectively. During the study, each participant tested positive for a mean of 14 HPV types. Cumulatively, HPV 16 was detected in 29 of 40 participants (72.5%). Mean duration of high- and low-risk infections was 655.9 (median: 433) and 524.1 days (median: 334), respectively. With prolonged follow-up, HPV infections with multiple types were found in all participants. Most had infection with HPV-16 or HPV-18, the oncogenic types represented in current vaccines, as well as infection with other oncogenic types. These data reinforce the importance of vaccine and non-vaccine strategies for prevention of HPV infections.