Semen Can Carry More Deadly Diseases Than We Thought

Studies have long established the sexual transmissibility of many viruses via semen, but new research shows troubling evidence that these diseases go far beyond the to-be-expected sexually transmitted infections. 

The study, published Dec. 10 in The Lancet Microbe journal, analyzed data from hundreds of studies and narrowed the findings down to 22 viruses capable of living in human semen after infection. Of these, nine showed evidence of sexual transmission. This builds upon more recent findings that viruses like Ebola and Zika can infect the male reproductive tract and continue to spread long after initial infection. 

"Many viruses and virus families can persist in human semen following acute infection, and some of these viruses have evidence for sexual transmission. Establishment of latent infection in the male reproductive tract and virus shedding in semen is probably more common than currently considered," the authors wrote in the study. 

As a result, more research needs to be done to confirm just what disease pathogens in semen can do and how transmissibility varies by virus. "An improved understanding of the role of semen in virus transmission is of great value for public health, most notably in the response to outbreaks of high-consequence viral pathogens," they said. 

Related: Study Links Smartphone Use to a Decline in Sperm Concentration

Evidence for sexual transmission was found for adenovirus, Andes orthohantavirus, hepatitis E virus, Marburg virus, monkeypox virus, West Nile virus, dengue virus, Ebola virus, and Zika virus. The team also found evidence for sexual transmission of Crimean–Congo hemorrhagic fever, hepatitis A virus, and vaccinia virus but no evidence for detection in semen. Notably, SARS-CoV-2, the virus that causes COVID-19, has been found in male reproductive tissues like the testis and prostate but hasn't been found to transmit through sexual contact. 

Maintaining a healthy immune system, the scientists concluded, is key to preventing viral infection in the first place as well as transmission both in sexual and non-sexual settings. Time to load up on vitamin C this cold and flu season.