By Dr. Andrew Y. Sun

 

Does COVID-19 affect male fertility?

The brief answer is that COVID-19 could affect male fertility, but likely only in the short run.

Given the novel nature of this disease, we do not have a ton of information specific to COVID-19 and sperm, however we can extrapolate from what we do know about similar viruses and flus. It has long been established that many types of fever-inducing illness, most commonly seasonal flu, can cause a temporary impairment of sperm generation, presumably as a result of overheating. Sperm require a very delicate temperature balance to thrive, and alterations in testicular temperature can have a drastic impact on sperm quality. This is also the reason why men trying to conceive should be counseled to avoid hot tubs and saunas, because of the same excess heat. There is also evidence that this can affect global testicular function as well, impacting the production of testosterone. Fortunately, this effect is transient and testicular function returns to normal after the acute illness resolves.

Given that fevers are a common symptom of COVID-19, it is reasonable to expect that acute illness with COVID-19 will similarly impair sperm generation and testicular function.  A preliminary study conducted compared the levels of reproduction-related hormones in 81 men who had COVID-19 and 100 men who did not.  The study found that the men with COVID-19 did show decreased levels of reproduction-related hormones, but not in testosterone levels. This study, however, did not look at the sperm counts or quality, and has yet to be verified.

Are there any long lasting effects of COVID-19 on male fertility?

There are some viruses, most notably Mumps, that can cause something called viral orchitis. This is a severe inflammation/infection of the testicles, which, when it occurs in adolescents and young boys, can cause permanent damage to the testicles and lead to infertility. Studies on Severe acute respiratory syndrome (SARS), which is from the same coronavirus class as COVID-19, revealed that some patients developed viral orchitis as a part of the disease. Testicular tissue expresses a high amount of the enzyme ACE2, which the SARS-COV-2 viruses bind to as a part of how they infect cells. Therefore, it is theoretically possible that COVID-19 may cause a similar effect on the testicles. However, it is important to note that to date, this is still purely speculative, and there have been no reported cases of testicular infection associated with COVID-19 at this point.

Can COVID-19 be sexually transmitted?

This is still an area of ongoing research at this time, and the literature is mixed. Two early reports looked at the semen of men infected with COVID-19 and both found no evidence of virus in the semen. However, a subsequent study was just published which looked both at men who have achieved clinical recovery from COVID-19 and those with active COVID-19 infection. They found that six out of 38 patients (15.8%) had SARS-CoV-2 in their semen, including four of 15 patients (26.7%) who were at the acute stage of infection and two of 23 patients (8.7%) who were clinically recovering.

Notably, these results do not necessarily prove that COVID-19 can be sexually transmitted, nor does it have any implication on sperm quality.  Additional research needs to be done before we can make definitive conclusions in this area. Transmission during sex is most likely to occur by the same mechanism that COVID-19 generally spreads - respiratory droplets spread between partners in close contact.

Final thoughts

There is much that is unknown about COVID-19 and male fertility at this time, and research is emerging. Here’s what we know:

  • Fevers associated with acute viral infections of many types can temporarily impair sperm production due to excess heat.
  • There is a theoretical risk of viral orchitis related to COVID-19, but this has not yet been found in patients.
  • There is mixed evidence that SARS-Cov-2 virus may be found in the semen, but the broader implications of this are unclear.

Although we are still learning about how COVID-19 is transmitted, we recommend continued handwashing practices, social distancing measures, covering of the mouth and nose when in public, and regular disinfection of frequently touched surfaces. If you have active infection with COVID-19, it may be prudent to avoid intercourse until you recover.

For more on male fertility, check out the Male Fertility section of our blog.