Long-term persistence of oral HPV over 7 years of follow-up

Background: Human papillomavirus-related oropharyngeal cancer (HPV-OPC) incidence is increasing, but the natural history of the precursor-oral HPV-has not been well described. Methods: This observational cohort study of people living with HIV and at-risk HIV uninfected people evaluated participants semiannually using 30-second oral rinse and gargle specimens over 7 years. Initially, 447 participants were followed for 4 years as part of the Persistent Oral Papillomavirus Study, and a subset of 128 who showed persistent infections at the last Persistent Oral Papillomavirus Study visit had an additional visit, as part of the Men and Women Understanding Throat HPV Study, on average 2.5 years later. Extracted DNA from oral rinse and gargle specimens was amplified using polymerase chain reaction and type specification of 13 oncogenic HPV types. Risk factors for oncogenic oral HPV clearance were evaluated using Cox models. Results: The majority of oncogenic oral HPV infections cleared quickly, with a median time to clearance of 1.4 years (interquartile range =0.5-3.9 years). After 7 years of follow-up, 97% of incident and 71% of prevalent infections had cleared. Lower HPV-16 viral load was statistically significantly associated with clearance (per 10-fold decrease in copy number: adjusted hazard ratio [aHR] = 2.51, 95% confidence interval [CI] = 1.20 to 5.26; P = .01). Adjusted analyses showed that oncogenic oral HPV clearance was lower among prevalent than incidentdetected infections (aHR=0.44, 95% CI=0.35 to 0.55), among men than women (aHR=0.74, 95% CI=0.60 to 0.91), for older participants (aHR per 10 years increasing age=0.81, 95% CI=0.74 to 0.89), and among people living with HIV (aHR=0.76, 95% CI=0.60 to 0.95). One participant who had oral HPV-16 consistently detected at 10 study visits over 4.5 years was subsequently diagnosed with HPV-OPC. Conclusions: This prospective study of oncogenic oral HPV infection is the longest and largest quantification of oral HPV-16 infections to date.