Prevalence, Genotype Distribution, and Predictors against HPV Infections Targeted by 2-, 4-, 9-Valent HPV Vaccines among Japanese Males

Objectives: Epidemiological reports of sexual life and human papilloma virus (HPV) infection among Japanese men are scarce, and the necessity of HPV vaccines for males is regarded as a controversial topic in Japan. The objective of this study is to determine the prevalence, genotype distribution, and risk factors against HPV infections targeted by bivalent (2v), quadrivalent (4v), and 9-valent (9v) HPV vaccines among Japanese male patients who visited our urological clinics. Material and Methods: The study population consisted of 798 males aged 20 to 95 years (mean ± standard deviation, 55.4 ± 19.5 years). We collected scraping samples from the glans penis using cotton swabs from all patients for genotyping of HPVs. We compared patients’ characteristics and detected HPV genotypes in order to determine the risk factors against HPV infections. Results: Of 798 participants, 198 participants (198/798; 24.8%) had at least one genotype of any HPV infection. The total number of detected HPV genotypes was 328. Of 328 genotypes, 30% (n = 99; 99/328) were 9v HPV genotypes. Most frequently detected types of high-risk HPV infection were type 52 (n = 40; 40/328; 12.2%). Number of lifetime sex partners (≥21) and present or history of sexually transmitted infections were found to be predictors of any HPV infection with adjusted odds ratios of 3.106 (95% confidence interval (CI), 1.593–6.509) and 1.894 (95% CI, 1.185–3.026), respectively. Age of sex initiation was a predictor of 2v and 4v HPV infections with adjusted odds ratios of 100 (95% CI, 1.013–25.673) and 2.676 (95% CI, 1.037–6.905), respectively. Number of lifetime sex partners (≥21) was a predictor of 9v HPVs with adjusted odds ratios of 2.397 (95% CI, 1.060–5.424). Conclusions: Approximately, a quarter of Japanese male patients who visited urological clinics were exposed to HPV. Moreover, from the perspective of our multivariate logistic regression analysis, some kinds of sexual behavior aggravate the risk of typical HPV genotypes infections.

From Ancient to Emerging Infections: The Odyssey of Viruses in the Male Genital Tract

The male genital tract (MGT) is the target of a number of viral infections that can have deleterious consequences at the individual, offspring, and population levels. These consequences include infertility, cancers of male organs, transmission to the embryo/fetal development abnormalities, and sexual dissemination of major viral pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus. Lately, two emerging viruses, Zika and Ebola, have additionally revealed that the human MGT can constitute a reservoir for viruses cleared from peripheral circulation by the immune system, leading to their sexual transmission by cured men. This represents a concern for future epidemics and further underlines the need for a better understanding of the interplay between viruses and the MGT. We review here how viruses, from ancient viruses that integrated the germline during evolution through old viruses (e.g., papillomaviruses originating from Neanderthals) and more modern sexually transmitted infections (e.g., simian zoonotic HIV) to emerging viruses (e.g., Ebola and Zika) take advantage of genital tract colonization for horizontal dissemination, viral persistence, vertical transmission, and endogenization. The MGT immune responses to viruses and the impact of these infections are discussed. We summarize the latest data regarding the sources of viruses in semen and the complex role of this body fluid in sexual transmission. Finally, we introduce key animal findings that are relevant for our understanding of viral infection and persistence in the human MGT and suggest future research directions.