Oral prevalence and clearance of oncogenic human papilloma virus in a rehabilitation community for substance abusers in Italy: a case of behavioral correction?

Background: Human papilloma virus oral infection can be related to several factors including HIV infection, cigarette smoking, marijuana consumption and number of sexual partners. We conducted a study on oral HPV prevalence and clearance among the hosts of the San Patrignano community, a population considered at "high-risk" for HPV due to their previous habits.

Methods: From March 2007 to September 2010 all subjects were submitted to oropharyngeal brushing and saliva collection at baseline, after 6, 12 and 48 months (for subjects HPV positive at baseline). Samples were analyzed to detect HPV DNA and virus genotypes. The correlation between HPV prevalence and demographic, behavioral or immunological characteristics was assessed.

Results: Among 194 subjects, 30 (15%) were HPV positive with 25 (13%) high-risk (HR)-HPV at baseline brushing. At 12 months HPV infection was cleared in all cases. However at 48 months HPV was newly detected in 33% of subjects. A correlation between time spent in the community and increase in the ratio of "low-risk" (LR) HPV and HR-HPV was observed. HPV infection was not associated with age, gender, HIV status, HCV, alcohol and/or drug exposure, number of years spent in community, sex with drug-addicts and condom use. Only AIDS under antiretroviral treatment was inversely correlated with the risk of infection.

Conclusions: At 1 year a complete HPV clearance was observed which could be related to adoption of healthier lifestyles of participants. New HPV infections were detected even in the absence of the recognized and declared risky behavioral factors, suggesting a re-expression from a latent infection.