We asked Dr Javier Ruiz Romero, the medical director of Reproclinic, to explain how SARS-CoV-2 acts on reproductive function and to answer such troubling questions as:
- Does COVID19 pose a threat to male fertility?
- Is this decrease in sperm production a transient and therefore reversible phenomenon?
- How should we proceed if we have evidence that COVID-19 can alter sperm production?
- If you have not yet passed COVID-19, why not freeze your sperm?
- And can the vaccine alter sperm production?
- Should I be vaccinated if my partner is going to undergo assisted reproduction treatment?
We have observed several young men who, after suffering COVID-19 with no apparent general symptoms and no genital manifestations, have presented a considerable reduction in sperm count. In addition, there are scientific studies that establish pathophysiological mechanisms that would link the action of the SARS-CoV-2 virus in the testicles with a decrease in sperm production. However, for the moment, we cannot establish a pattern, nor do we know why it affects some men and not others. Nor do we know whether this is a transient and reversible phenomenon or whether it is permanent damage.
We do know that the male reproductive system is a vulnerable target for infection by the virus and, therefore, in the clinic, we remain alert to the possibility that it may induce alterations in male fertility, leading to a decrease, reversible or not, in sperm production.
Does COVID19 Pose A Threat To Male Fertility?
The SARS-CoV-2 virus and COVID-19 disease are entities with massive population involvement and high transmissibility, which has led to an unprecedented public health emergency in a short evolution time. However, despite the enormous spread and scale of the impact, knowledge of the adverse effects that SARS-CoV-2 may have on male reproductive health is still very limited in the short and long term.
The viral infection has a disease incubation period of five days on average (between 2 and 14 days). In the course of the disease, the first phase of the viral response of the infection has been described, followed by a phase of the hyperinflammatory response. The predominant clinical manifestations are respiratory, although multiple organs and system involvement and even orchitis (testicular inflammation) have been observed.
The presence of the ACE2 enzyme may be one of the main determinants of cell susceptibility to SARS-CoV-2 infection and a gateway for the virus to enter the cell. ACE2 is expressed in different human tissues such as the lungs, kidneys, brain, vascular endothelium and especially the small intestine and testis. So while it makes sense that the focus should rightly be on the vital organ systems (lung, kidney and heart) that are vulnerable to viral attack and contribute to the acute pathology associated with this disease, we should not lose sight of the fact that COVID-19 will attack any cell type in the body that expresses CEA2, including human sperm.
The testis has been shown in sperm-producing cells in a similar percentage as in lung cells that are directly involved in the pathogenesis of COVID-19. It also appears that ACE2 expression in the testis is inversely proportional to the age of the male; thus, the maximum level of ACE2 expression would be recorded in individuals aged 30 years, which would make them more susceptible to the effects of SARS-CoV-2, constituting an obvious threat to their fertility.
At Reproclinic, we have observed several young men who, after undergoing COVID19 with no apparent general symptoms and no genital manifestations, have presented a considerable reduction in sperm count. One of them even presented azoospermia without obvious symptoms or fever and without any change in the values of the hormones that control sperm production. For the moment, we cannot establish a pattern, nor do we know why it affects some men and not others. However, we can say that the ACE2 enzyme seems to play a key role in sperm formation, as testicular levels of this enzyme are significantly lower in men with severe alterations in sperm production than in those with normal sperm formation. It has also been observed that male sex hormones decrease in patients with COVID-19 at the time of admission to the ICU, with low levels of testosterone and dihydrotestosterone; however, this phenomenon could be more related to the stress caused by the situation or to other symptoms linked to the infection itself.
Is this decrease in sperm production a transitory and therefore reversible phenomenon?
We cannot say yet, but it seems that after 6 months, a slow recovery begins. We are waiting for the definitive results of our patients and the studies being carried out in other reproduction centres in the world to evaluate the recovery capacity of the testicles in the face of the impact of the SARS-CoV-2 virus. We do not know when and to what extent they will recover their sperm function.
How should we proceed if we have evidence that COVID19 can alter sperm production?
This is not a situation that should cause alarm; however, if you are a male of childbearing age and have been infected with COVID19, we would recommend that you:
- First, have a semen analysis (sperm number and quality).
- Visit an andrologist whose advice on lifestyle, diet and treatment can speed up your recovery.
If you have not yet been infected with COVID19, why not freeze your sperm?
Preserving your fertility will ensure that you will be able to have offspring regardless of whether you have a decrease in sperm production later on, whether due to COVID19 or another health problem. In fertility, prevention is a good strategy.
What about the vaccine, can it affect sperm production?
Because the available COVID-19 vaccines are not composed of live viruses, they are not thought to increase the risk of infertility. The only thing to be aware of is the possible side effects of vaccination, such as fever. If high and sustained, it could affect sperm maturation and spermatogenesis. However, no scientific data is showing any benefit in delaying vaccination, and it is certainly much wiser to get vaccinated than to expose oneself to infection.
The real impact and reproductive consequences of SARS-CoV-2 infection in young males are currently unknown. However, we must highlight the evidence that the male reproductive system is a vulnerable target for infection by the virus and; therefore, we must remain vigilant to the possibility that it may induce alterations in male fertility, leading to a decrease, reversible or not, in sperm production. Therefore, we must recommend patients be vaccinated.
Dr. Javier Ruiz Romero, medical director of Reproclinic