Sperm study recommends quarantine after COVID-19

Brazilian researchers have discovered the COVID-19 virus in sperm up to 3 months after infection, which they say should make people think carefully about the time babies might be conceived.

Details of the new study, in the journal Andrology, revealed the virus that causes COVID-19, SARS-CoV-2, can remain inside sperm for up to 3 months following hospital discharge (100-110 days after initial infection).

Based on their results, the researchers from the University of São Paulo (FM-USP) in Brazil advocate postponing natural conception and assisted reproductive techniques for up to 6 months (2 cycles of sperm cell production) after a COVID-19 infection.

Corresponding author Jorge Hallak, a urology specialist and professor of medicine at FM-USP, says the finding is a “scientific paradigm shift”.

The study also revealed that infected sperm produce “extracellular traps”, a process in which the cell sacrifices itself to encircle and contain the pathogen. This is a known tactic used by neutrophils and other white blood cells which are the body’ first line of defence against infection.

“The finding that spermatozoa are part of the innate immune system and help defend the organism against attack by pathogens is unique in the literature and makes the study very important,” says Hallak.

The discovery adds a new function to sperm’s role in reproduction.

SARS-Cov-2 is able to invade several types of human cells and tissues, including the testes. However, it is rarely detected in semen by polymerase chain reaction (PCR) analysis, which focuses on viral DNA. 

This study used real-time PCR and transmission electronic microscopy (TEM) to detect viral RNA in semen and spermatozoa donated by 13 patients recovering from COVID-19. Semen samples were taken from the patients, aged between 21 and 50 years, who had had mild, moderate and severe COVID-19.

Although the PCR test results were negative for SARS-CoV-2 in semen in all cases, TEM detected the virus inside the sperm of 9 of the 13 patients (69.2%) up to 90 days after being discharged from hospital.

Two other patients had sperm with structural impairment similar to that seen in patients with a COVID-19 diagnosis. The authors therefore concluded that 11 of the patients had the virus in their sperm. 

According to the authors it is not known at this time whether these virus-carrying sperm are capable of fertilising an oocyte (egg cell) by natural conception or assisted reproduction technology.

“It is also not known whether the virus will subsequently be transmitted to the developing embryo and what detrimental consequences might have on foetuses,” they write.

“We must be cautious in the management of male patients infected with SARS-CoV-2, especially when they have the desire to conceive, regardless of the severity of their COVID-19.”

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