It has long been known that Covid-19 is not only a respiratory disease, but can also attack other parts of the body. The corona-Virus enters the lungs, blood and other organs, for example through the respiratory tract liver, kidney and brain. In principle, Sars-CoV-2 can dock anywhere where cells have ACE-2 receptors and a certain enzyme (TMPRSS2) on their surface. This is also the case, for example, in the testicles, where the viruses have already been detected.
Nine of the thirteen test subjects had RNA from the coronavirus in their semen
Researchers from the University of São Paulo Brazil could now do this within the framework of one study show that the virus can still be detected in semen 110 days, i.e. more than three months, after the acute infection and also affects semen quality. Because the tests were only carried out during this period, coronaviruses may be present there for longer.
The researchers investigated this for the small study sperm of 13 patients aged 21 and 50 who had been treated in hospital with mild to severe cases of Covid-19. A PCR test could not detect the virus in the semen. But with the transmission electron microscope (TEM), the researchers got a completely different picture: up to 90 days after discharge from the hospital and therefore up to 110 days after infection, they were able to detect viral RNA of the coronavirus in the semen of nine of the 13 test subjects .
Infected sperm kills itself to kill pathogens
But a look into the electron microscope revealed much more important findings: the Corona-infected sperm produced so-called ‘extracellular traps’. This is an immunological mechanism known scientifically as an extracellular neutrophil trap (NET for short). This is mainly used by a sub-type of white blood cells (neutrophilic leukocytes) to fight bacteria, fungi and viruses. However, if this mechanism becomes overactive, it can also damage the body.
In the case of sperm, the researchers were able to see that the sperm cells sacrifice themselves, as it were, to surround and kill the pathogen – in this case the coronavirus. The researchers call this mechanism a ‘suicidal ETosis-like reaction’.
Sperm is part of the innate immune system
This is a groundbreaking finding for science: “…the fact that sperm functions as part of the innate immune system against invaders makes the study of great importance,” says the lead researcher, Jorge Hallak, in University Journal . So it’s a paradigm shift in science. Because so far only obvious functions of sperm are known, such as:
- to transport the genetic contents of the male sex cell to the female sex cell,
- the fertilization of the female sex cell,
- to promote embryonic development up to the twelfth week of pregnancy.
Delay reproduction for at least six months after infection
The discovery of the Brazilian researchers is of great importance for reproduction: because of these immunological processes and to be on the safe side, Hallak recommends postponing natural fertilization and especially assisted reproduction for at least six months after a Sars-CoV-2 infection. In some affected people, the virus may also be active for longer in the semen. The scientist warns that this applies even to mild Covid-19 diseases.
It is not yet known whether the virus-carrying sperm cells are able to fertilize an egg. However, we also do not know whether the virus can be transmitted to the developing embryo and what potentially harmful consequences this may have.
“We must be careful when treating male patients infected with Sars-CoV-2, especially if they want to have children, regardless of the severity of their illness from Covid-19,” Hallak warns.