Human papillomavirus in semen and the risk for male infertility: a systematic review and meta-analysis

Background: Human papillomavirus (HPV) is one of the most prevalent sexually transmitted viruses. Despite the increasing evidence of HPV prevalence in semen, the worldwide distribution of HPV types in semen and risk for male infertility remain inconclusive. Methods: Four electronic databases were searched for English language studies conducted between January 1990 and December 2016 that reported HPV DNA prevalence in semen. Based on the PRISMA guidelines, HPV prevalence was estimated among general population and fertility clinic attendees, respectively, and heterogeneity testing was performed using Cochran's Q and I-2 statistics. The association between HPV positivity and male infertility was evaluated by a meta-analysis of case-control studies. Results: A total of 31 eligible studies comprising 5194 males were included. The overall prevalence of HPV DNA in semen was 11.4% (95% CI = 7.8-15.0%) in general population (n = 2122) and 20.4% (95% CI = 16.2-24.6%) in fertility clinic attendees (n = 3072). High-risk type prevalence was 10.0% (95% CI = 5.9-14.0%) and 15.5% (95% CI = 11.4-19. 7%), respectively. HPV16 was the most common type, with a prevalence of 4.8% (95% CI = 1.7-7.8%) in general population and 6.0% (95% CI = 3.8-8.2%) in fertility clinic attendees. A significantly increased risk of infertility was found for males with HPV positivity in semen (OR = 2.93, 95% CI = 2.03-4.24). Conclusions: Seminal HPV infection is common worldwide, which may contribute to the risk of male infertility.