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COVID-19 Infects Penis And Testicles, Causing Complications, Suggests Monkey Study


Jack Dunhill


Jack Dunhill

Social Media Coordinator and Staff Writer

Jack is a Social Media Coordinator and Staff Writer for IFLScience, with a degree in Medical Genetics specializing in Immunology.

Social Media Coordinator and Staff Writer

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A PET scan of the macaques, where glowing regions indicate infection, cropped from a figure. Image Credit: Madden et al., 2022/CC-BY-NC-ND-4.0

After studying large mammals infected with COVID-19, scientists made a surprising discovery. The virus was not just spreading to the expected organs, but also through the entire male genital tract – penis, testicles, and prostate included.

The team believes this to be strong evidence that the virus directly infects cells within this area, resulting in sperm count decline, decreased fertility, and even erectile dysfunction. 


Their results are published as a preprint in bioRxiv, meaning it is yet to be peer-reviewed. 

It was previously thought that the reported testicle pain was a result of indirect damage through the immune response reacting to infection, causing inflammation that damaged tissue around the genital tract. However, researchers found the virus was actively infecting cells in the penis and testicles. 

“These results indicate that the testicular pain, erectile dysfunction, hypogonadism, reduced sperm count and quality, and decreased fertility associated with SARS-CoV-2 infection are a direct consequence of infection of cells of the male reproductive tract and not indirect mechanisms such as fever and inflammation,” said lead author Thomas Hope, professor of cell and developmental biology at Northwestern Feinberg School of Medicine, in a statement

The infection was discovered using a full-body PET scan of Rhesus macaques while attempting to characterize the virus spread throughout the bodies of large mammals over time.


Taking numerous PET (positron emission tomography) and CT (computed tomography) scans at different time points during infection with SARS-CoV-2, a strong signal was found in the genital tract of all three animals studied. Throughout the vasculature of the penis, testicles, and prostate, scans highlighted a large number of infected cells plus some signals from the epididymis, which stores and transports sperm.  

These signals were later confirmed by tissue analysis, and one of the macaques suffered from severe problems in its testes just two weeks after infection. When another group was then infected with the Delta variant, signals were discovered in the lungs, heart, prostate, and both testes. 

It is likely this infection may be causing the strong evidence of genital pathology in people with COVID-19, which until now puzzled scientists.  

A figure showing the possible complications resulting from COVID-19 infection. Image Credit: Madden et al., 2022/ CC-BY-NC-ND-4.0

Studies are not conclusive on the percentage of men that have reproductive issues as a result of COVID-19, but sperm mobility changes were seen in 60 percent of men post-infection in one study. With case numbers still so high across the world, millions of men may have and could be affected. 


“Even if this is only a small percentage of the infected, it represents millions of men who may suffer from a negative impact on their sexual health and fertility,” Hope said.  

“The potential impact of SARS-CoV-2 infection on sexual and reproductive health should be part of everyone’s decision to get vaccinated to minimize the chance of death, severe disease and hospitalization, and infection of the prostate, penis, testicles and vasculature (blood supply) of testicles.” 

This study was conducted in rhesus macaques, suggesting that the results likely translate to humans, but this cannot be confirmed. It is also awaiting peer review, so should be considered as preliminary data until fully published. 


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