While most studies on COVID-19’s effect on fertility have focused on women, emerging research on men is starting to show that the infection may lead to a temporary dip in male fertility and sexual function. A study published in November 2021 in the Journal of Endocrinological Investigation found that men who’d had COVID-19 were over 3 times more likely to experience erectile dysfunction than men who’d not had COVID-19. Still, this accounted for less than 5 percent of people in the study who’d been infected. According to Kevin Chu, MD, an andrology fellow at the University of Miami, the discovery of the coronavirus in penile and testicular tissue raised questions that required answers. “Finding virus in this tissue is what first drove researchers to look at certain parts of the body that weren’t initially looked at,” says Dr. Chu. “There is still so much we don’t know.”
Can COVID-19 Lead to Erectile Dysfunction?
For a study published in February 2022 in the journal Sexual Medicine, Chu and his coauthors hypothesized that because COVID-19 can result in the constriction of blood vessels around the heart, it might affect a man’s ability to have an erection. “You need good blood flow into the penis to get good erections, and if that’s impacted, that could cause erectile dysfunction,” says Chu. He and his team reviewed electronic medical records of millions of patients in the United States, identifying over 230,000 adult men who had COVID-19 and comparing them with a similar number of men who were not infected. Their conclusion: COVID-19 can be linked to erectile dysfunction. According to Chu, experts should continue to review new data as it comes out. “Looking for associations is an important first step, but we need to then identify these cause-and-effect correlations,” he says. It’s important to note that erections are not purely biological. “They require psychosocial factors and that needs to be looked at, too,” Chu says, explaining that the mental strain from being sick or even the stress of the pandemic might come into play. Scientists have long documented the toll that stress takes on libido and sexual function, but the research on how pandemic-related stress is affecting people’s sex lives has produced mixed results. A meta-analysis published in January 2022 in the journal BMC Public Health looked at 26 studies involving nearly 2,500 women and 3,800 men. Overall, the researchers found that there was an association between the COVID-19 pandemic and reduced sexual activity, especially in women, and that fear of contracting or transmitting COVID-19 had the greatest impact on the occurrence of sexual dysfunction. But a small study published in February 2021 in the journal Sexual Medicine, which included 76 male cannabis users, found that the pandemic didn’t appear to influence sexual function and actually increased sexual activity.
Can COVID-19 Affect Male Fertility?
The research on how COVID-19 may impact male fertility is also new, but a growing body of evidence suggests it might have a negative effect, at least in the short term. A study of 120 men published in February 2022 in the journal Fertility and Sterility found that 60 percent of those who’d had COVID-19 experienced reduced sperm motility (referring to sperm’s ability to move) in the month following infection, even though the virus was not detected in the sperm itself. Because the research is still new, it’s not clear how long this drop in fertility lasts, though the authors estimated around three months. A separate study, published in January 2022 in the American Journal of Epidemiology, included more than 2,100 couples. Researchers found that while COVID-19 in women didn’t appear to impair their ability to get pregnant, COVID-19 in men did seem to reduce fertility. Compared with males who did not have COVID-19 within the last 60 days, men who did were almost 20 percent less likely to conceive during that time frame. “We assume that the effects won’t be permanent but we don’t know that yet,” says Chas Easley, PhD, an associate professor of environmental health science at the University of Georgia School of Public Health in Athens, who was not involved with the research. According to Dr. Easley, all viruses target different receptors, or proteins, to gain entry into cells. The coronavirus behind COVID-19 targets two proteins: ACE2 and TMPRSS2. Easley and some other experts hypothesize that organs that contain both these proteins are particularly susceptible to infection by the COVID-19 virus. The testes, which are the organs responsible for making sperm, contain both. Sertoli cells, a type of cell in the testes, also contain these proteins. These cells form a physical barrier that separates blood vessels from the testes, called the blood-testis barrier. When the virus latches onto these proteins, it disrupts the function of Sertoli cells in multiple ways. “If you screw up the Sertoli cells, you lose the ability to promote the spermiogenesis required to create real sperm,” says Easley. He advises people who’ve had COVID-19 and are having difficulty conceiving to consider testing to evaluate sperm count and sperm motility.
Do COVID-19 Vaccines Make Men Infertile?
According to Easley, none of the COVID-19 vaccines reduce male fertility. “The vaccine can’t cause infertility — but the virus can,” he says. The study published in January 2022 in the American Journal of Epidemiology found no difference in male or female fertility among uninfected people who were vaccinated with the Pfizer-BioNTech, Moderna, or Johnson & Johnson COVID-19 vaccines compared with uninfected people who were not vaccinated. The new study backs up prior research on mRNA vaccines. An investigation published in June 2021 in JAMA, which included 45 men who received two doses of an mRNA COVID-19 vaccine, found that the vaccine did not lower sperm counts. In fact, sperm counts increased, from a median count of 26 million per milliliter at baseline to 30 million per milliliter after the second shot. According to Easley, getting vaccinated against COVID-19 is an important way for men to protect their fertility. “Even mild cases of COVID can lead to decreased sperm counts, lower sperm motility, and increased DNA fragmentation in sperm, and we predict that vaccines will prevent this damage,” he says.
