Evidence suggests COVID-19 isn’t sexually transmitted

Summary: Previous studies report COVID-19 may be present in the testes. Researchers report coronavirus is unlikely to spread via semen, and the chances of the infection being spread through sexual transmission are remote.

Source: University of Utah Health

COVID-19 is unlikely to be spread through semen, according to University of Utah Health scientists who participated in an international study of Chinese men who recently had the disease. The researchers found no evidence of the virus that causes COVID-19 in the semen or testes of the men.

The study was not comprehensive enough to fully rule out the possibility that the disease could be sexually transmitted. However, the chances of it occurring, based on this limited finding, appear to be remote.

“The fact that in this small, preliminary study that it appears the virus that causes COVID-19 doesn’t show up in the testes or semen could be an important finding,” says James M. Hotaling, M.D., a co-author of the study and a U of U Health associate professor of urology specializing in male fertility. “If a disease like COVID-19 were sexually transmittable that would have major implications for disease prevention and could have serious consequences for a man’s long-term reproductive health.”

The study appears in Fertility & Sterility, a peer-reviewed journal published by the American Society of Reproductive Medicine.

The international team of researchers from China and the United States launched the study in response to concerns that SARS-CoV-2, the virus that causes COVID-19, could be sexually transmitted like Ebola, Zika and other emerging viral pathogens. To find out, they collected semen samples from 34 Chinese men one month (on average) after they were diagnosed with mild to moderate cases of COVID-19. Laboratory tests did not detect SARS-CoV-2 in any of the semen samples.

But just because the virus wasn’t present in the existing semen didn’t necessary rule out that it hadn’t entered the testes where sperm cells are formed.

“If the virus is in the testes but not the sperm it can’t be sexually transmitted,” says Jingtao Guo, Ph.D., a postdoctoral scientist at the Huntsman Cancer Institute at the University of Utah who also co-authored the study.

“But if it is in the testes, it can cause long-term damage to semen and sperm production.”

To sort this part of the puzzle out, the researchers analyzed a dataset generated from a single cell mRNA atlas from healthy young organ donors that was available from prior work. This atlas allows them to examine mRNA, the genetic material used to make proteins, in any single testicular cell. In this case, scientist used it to examine the expression of a pair of genes associated with SARS-CoV-2. These two genes, angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) act as receptors, allowing SARS-CoV2 to penetrate cells and replicate. In order for the virus to access cells effectively, both receptors must be present in the same cell.

When the scientists examined the dataset, they found that genes encoding these two proteins were only found in four of the 6,500 testicular cells, suggesting that SARS-CoV-2 is unlikely to invade human testicular cells, Guo says.

Despite these findings, the researchers acknowledge that their study has several important limitations including a small sample size and the fact that none of the donors had been severely ill with COVID-19.

This shows people kissing in masks
But just because the virus wasn’t present in the existing semen didn’t necessary rule out that it hadn’t entered the testes where sperm cells are formed. Image is in the public domain.

“It could be that a man who is critically ill with COVID-19 might have a higher viral load, which could lead to a greater likelihood of infecting the semen. We just don’t have the answer to that right now,” Hotaling says. “But knowing that we didn’t find that kind of activity among the patients in this study who were recovering from mild to moderate forms of the disease is reassuring.”

However, Hotaling warns that intimate contact can still increase the risk of spreading the disease through coughing, sneezing and kissing. In addition, some infected people are asymptomatic and can appear healthy, even as they pass the virus along to others.

In addition to Drs. Hotaling and Guo, other U of U Health researchers involved in this study titled, “No Evidence of SARS-CoV-2 in Semen of Males Recovering from COVID-19,” were Darshan Patel, MD, and Adam Spivak, MD.

Funding: The research was supported by the National Natural Science Foundation of China and the Huazhong University of Science & Technology.

About this coronavirus research article

University of Utah Health
Media Contacts:
Doug Dollemore – University of Utah Health
Image Source:
The image is in the public domain.

Original Research: Open access (pdf)
“No evidence of SARS-CoV-2 in semen of males recovering from COVID-19”. by Feng Pan, MD, Xingyuan Xiao, MD, Jingtao Guo, PhD, Yarong Song, MD, Honggang
Li, MD, Darshan P. Patel, MD, Adam M. Spivak, MD, Joseph, P. Alukal, MD, Xiaoping Zhang, MD, Chengliang Xiong, MD, Philip S. Li, MD, James M. Hotaling, MD, MS.
Fertility and Sterility doi:10.1016/j.fertnstert.2020.04.024


No evidence of SARS-CoV-2 in semen of males recovering from COVID-19

Objective: To describe detection of SARS-CoV-2 in seminal fluid of patients recovering from COVID-19 and describe the expression profile of ACE2 and TMPRSS2 within the testicle.

Design: observational, cross-sectional study

Setting: Tertiary referral center

Patients: Thirty-four adult Chinese males diagnosed with COVID-19 through confirmatory quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) from pharyngeal swab samples.

Intervention: None

Main Outcome Measures: Identification of SARS-CoV-2 on qRT-PCR of single ejaculated semen samples. Semen quality was not assessed. Expression patterns of ACE2 and TMPRSS2 in the human testis are explored through previously published single-cell transcriptome datasets.

Results: Six patients (19%) demonstrated scrotal discomfort concerning for viral orchitis around the time of COVID-19 confirmation. SARS-CoV-2 was not detected in semen after a median of 31 days (IQR: 29-36 days) from COVID-19 diagnosis. Single-cell transcriptome analysis demonstrates sparse expression of ACE2 and TMPRSS2, with almost no overlapping gene expression.

Conclusions: SARS-CoV-2 was not detected in the semen of patients recovering from COVID19 one month after COVID-19 diagnosis. ACE2-mediated viral entry of SARS-CoV-2 into target host cells is unlikely to occur within the human testicle based on ACE2 and TMPRSS2 expression. The long-term effects of SARS-CoV-2 on male reproductive function remain unknown.

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