Incidence and clearance of oral human papillomavirus infection: A population-based cohort study in rural China.

The natural history of oral human papillomavirus (HPV) infection which is linked with the increased incidence of oropharyngeal squamous cell cancer (OPSCC) has been incompletely studied. Oral swab specimens and questionnaire data were obtained bi-annually for up to 6 visits from 4314 healthy adults aged 25-69 in rural Anyang, China. HPV infection status was evaluated with PCR-based sequencing. Participants with at least two consecutive valid HPV results within the study period were included in the incidence and clearance analysis. Among 3289 participants included in this analysis (median follow-up time 18.3 months), incidence rates of mucosal HPV, oncogenic mucosal HPV and cutaneous HPV were 0.53 (95% CI: 0.39-0.73), 0.30 (95% CI: 0.20-0.46), and 4.17 (95% CI: 3.70-4.70) per 1,000 person-months respectively. Most newly acquired infections were cleared within one year. Recent practice of oral sex increased the risk of incident infection with mucosal HPV (Adjusted HR, 5.03; 95% CI, 1.16-21.73) and oncogenic mucosal HPV (Adjusted HR, 10.13; 95% CI, 2.14-48.06). Newly acquired oral mucosal HPV infections are rare and most are cleared within one year in rural Chinese. This study expands understanding of the natural history of oral HPV in countries with a lower incidence of HPV-OPSCC.