Researchers at the University of São Paulo (USP) in Brazil have demonstrated for the first time that SARS-CoV-2, the virus responsible for COVID-19, can persist in sperm for up to 90 days post-hospital discharge and up to 110 days after initial infection, reducing semen quality.
These findings suggest that individuals planning to conceive should consider a “quarantine” period post-recovery.
Covid invades the reproductive system
Four years into the pandemic, it is established that SARS-CoV-2 can invade various human cells and tissues, including the reproductive system, using the testicles as a gateway.
Despite previous observations of the virus in testicles, its presence in semen was rarely detected through polymerase chain reaction (PCR) analysis, which typically focuses on viral DNA.
Covid virus retention in sperm
To bridge this knowledge gap, the study employed real-time PCR and transmission electron microscopy (TEM) to identify viral RNA in semen and spermatozoa donated by men recovering from COVID-19.
The samples, collected from 13 patients aged 21 to 50, revealed that the Covid virus was present in the sperm of 69.2% of the patients, indicating significant virus retention in sperm even after recovery.
Neutrophil extracellular traps
“We found that the sperm produced ‘extracellular traps’ based on nuclear DNA, forming networks similar to those seen in the systemic inflammatory response to SARS-CoV-2,” said corresponding author Jorge Hallak, a professor at USP.
These traps, known as neutrophil extracellular traps (NETs), are typically formed by white blood cells to immobilize and kill pathogens. However, hyperactive NETs can damage tissue throughout the organism.
Sperm help defend against Covid infection
TEM analysis revealed that sperm engage in a suicidal ETosis-like response, where they sacrifice themselves to contain the pathogen.
“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. It can be considered a scientific paradigm shift,” Hallak said.
Traditionally, sperm are known for their roles in binding male and female gametes, fertilizing female gametes, promoting embryo development, and influencing the development of chronic diseases. This study adds a new function: participating in the innate immune response.
Postponing conception after Covid infection
The findings have significant implications for assisted reproduction techniques, particularly intracytoplasmic sperm injection (ICSI), which involves injecting a single spermatozoon into an egg.
Hallak recommends postponing natural conception and assisted reproduction for at least six months after infection by SARS-CoV-2.
Impacts of COVID-19 on sexual health
Hallak, who has been advocating for caution in reproduction protocols since the pandemic began, has conducted extensive research on the impact of COVID-19 on reproductive and sexual health.
His group’s studies have highlighted the increased risk of severe COVID-19 infection and mortality in men, potentially due to the abundance of ACE2 receptors and TMPRSS2 in testes.
In previous studies, Hallak’s group found a significant decrease in libido and sexual satisfaction among health workers during the pandemic.
The team also discovered that the testes are potential targets for SARS-CoV-2, causing subclinical epididymitis and severe testicular lesions associated with COVID-19.
Currently, Hallak’s team, along with Professor Carlos Carvalho and other researchers at USP, are investigating the long-term effects of SARS-CoV-2 infection in over 700 patients as part of a Thematic Project funded by FAPESP.
COVID-19 and reproductive health
COVID-19 can impact human reproductive health in several ways, though research is still ongoing to fully understand the extent and mechanisms.
Testicular damage
Some studies suggest that COVID-19 can cause testicular damage in infected individuals, potentially due to viral entry into cells via ACE2 receptors, which are abundant in testicular tissue.
This could lead to reduced testosterone levels and impaired sperm production, though the evidence is still emerging and not definitive.
Menstrual changes
There have been reports of menstrual irregularities in women who have contracted COVID-19. These changes include alterations in menstrual cycle length, volume of menstrual flow, and increased menstrual pain.
The exact cause isn’t well understood but could be related to the stress of illness, immune response, or other factors associated with the infection.
Fertility
There is limited data on the direct impact of COVID-19 on fertility. Some concerns were initially raised about potential impacts due to illness and fever, which can affect sperm and egg quality temporarily.
However, there is no conclusive evidence yet that COVID-19 leads to long-term fertility issues.
Pregnancy
Pregnant women with COVID-19 are at increased risk of severe illness and adverse pregnancy outcomes compared to pregnant women without COVID-19.
These risks include preterm birth and possibly other complications for both the mother and baby. However, vertical transmission (transmission from mother to baby during pregnancy) appears to be rare.
Further research is needed to better understand the full spectrum of COVID-19’s impact on reproductive health across different populations.
The study is published in the journal Andrology.