Human papillomavirus infection among male virgins and the potential for non-sexual transmission
It is assumed that the primary mode of genital transmission of HPV is by sexual activity through contact with infected cervical, vaginal, vulvar, penile or anal epithelium; however, a number of studies have found evidence of non-sexual transmission of HPV. If non-sexual transmission of HPV is non-trivial, then the lack of inclusion of non-sexual transmission routes may bias transmission dynamic and vaccine modeling studies. The goal of this study was to assess the potential of HPV for non-sexual transmission by (1) systematically reviewing studies with evidence of HPV being transmitted in ways other than vertically or through penetrative sex (i.e., penile-vaginal intercourse, penile-anal intercourse, and penile-oral intercourse); (2) determining the overall and type-specific prevalence, and factors associated with prevalence, of genital HPV infection among male virgins at baseline in the Human Papillomavirus Infection in Men Study (HIM Study) cohort; and (3) determining the incidence, persistence, and clearance of genital HPV infections among male virgins in the HIM Study cohort during a 4-year follow-up period and identifying risk factors associated with incidence and clearance of genital HPV infections among these men. Log-binomial regression models were used to produce estimates of prevalence ratios and 95% confidence intervals for three outcomes: any HPV type, high-risk types, and low-risk types. A Cox proportional hazards model was used to assess the association between possible risk factors and HPV incidence. The Kaplan-Meier method was used to estimate the median time to HPV clearance for any HPV type. The Cox proportional hazards model was used to assess the association between possible risk factors and HPV clearance.^ HPV DNA was detected in the genital tract of female virgins with prevalence estimates ranging from 0-51.2%. HPV transmission from hands to genitals or genitals to hands was reported for both sexes and heterosexual couples. Other studies commonly found HPV on surfaces in medical settings and public environments. The analyses of the HIM Study baseline data showed that the prevalence of any and high-risk HPV among 88 male virgins was 25.0% and 18.2%, respectively. Age and smoking status were associated with HPV prevalence. In HIM Study prospective data, the incidence rates for any HPV infection among virgins initiating sex (VIS) and virgins not initiating sex (VNIS) were 26.2 and 14.6 per 1000 person months, respectively. Of baseline virgins who initiated sex during follow-up, 28.7% and 45.5% acquired any HPV infection within 12 and 24 months of sex initiation, respectively. VNIS were more likely to clear high-risk HPV infection than non-virgins. Age, smoking status, number of female sex partners in the past 6 months, and baseline HPV infection status were associated with high-risk HPV clearance.^ Our studies demonstrated that HPV was prevalent among male virgins. VNIS may acquire HPV infection presumably through non-penetrative sexual contact. Male VIS acquired HPV infection at similar rate as female VIS. Further studies on non-sexual and non-penetrative sexual transmission are needed to better understand the complexity of HPV transmission.^
Liu, Zhiyue, "Human papillomavirus infection among male virgins and the potential for non-sexual transmission" (2016). Texas Medical Center Dissertations (via ProQuest). AAI10249212.