Oral human papillomavirus infection incidence and clearance: a systematic review of the literature

Subclinical oral human papillomavirus (HPV) infection that persists for decades is likely to precede an HPV-driven squamous cell carcinoma of the head and neck, but little is known about the natural history of oral HPV. We systematically reviewed and abstracted data from nine manuscripts that examined human immunodeficiency virusnegative and cancer-free subjects for oral HPV DNA to determine the pooled baseline prevalence and incidence of newly acquired oral HPV infections, and specifically for HPV-16. We also documented the clearance rate and the median time to clearance, where data existed. Of 3762 individuals, 7.5% had an oral infection with any HPV type (1.6% for HPV-16). Meta-regression analysis estimated the 12-month cumulative incidence to be 4.8% (95% confidence interval 3.2-7.3 %). The overall oral HPV clearance was reported to be 0-80% between studies, and the median time to clearance from 6.5 to 18 months. Oral HPV-16 clearance was 43-83 %, and median time to clearance for HPV-16 was 7-22 months. Oral HPV prevalence, incidence and clearance vary considerably between published studies from different geographical regions. Further research is required to identify predictors of persistent oral HPV infection. Measurable baseline prevalence was observed in all studies, as well as non-trivial incidence of newly acquired oral HPV infections and incomplete clearance.