For a respiratory disease, Covid-19 causes some peculiar symptoms. It can diminish the senses of smell and taste, leave patients with discolored “Covid toes,” or even cause a swollen, bumpy “Covid tongue.”
Now scientists are examining a possible link to an altogether unexpected consequence of Covid: erectile dysfunction. A connection has been reported in hundreds of papers by scientists in Europe and North America, as well as in Egypt, Turkey, Iran and Thailand.
Estimates of the magnitude of the problem vary wildly. A paper by Dr. Ranjith Ramasamy, director of reproductive urology at the University of Miami’s Desai Sethi Urology Institute, and his colleagues found that the risk of erectile dysfunction increased by 20 percent after a bout with Covid. Other investigators have reported substantially higher increases in that risk.
When patients first started coming to Dr. Ramasamy’s clinic complaining of erection problems, “We dismissed it, thinking it was all psychological or stress induced,” he said.
But over time, he and other physicians began to see a pattern, he said. “Six months after the initial infection, patients had gotten better overall, but they continued to complain of these problems,’’ including both erectile dysfunction and low sperm counts, Dr. Ramasamy, who has written several papers on the topic, said.
At the outset of the pandemic, Dr. Emmanuele Jannini, a professor of endocrinology and medical sexology at the University of Rome Tor Vergata, reported a strong link between erectile dysfunction and Covid. When he compared men who had been ill with Covid with those who had not, he found that those who had been infected were nearly six times as likely to report impotence as those who had avoided the coronavirus.
“Communicating that the disease can affect your sexual life is a tremendously powerful message,” especially for men who still resist vaccination, Dr. Jannini said in an interview. “The evidence is very strong.”
Research from imaging scans and biopsies indicates that the coronavirus can infect tissue within the male genital tract, where it may linger long after the initial infection. Scientists say it is too early to be certain that the link to erectile dysfunction is causal, since so many factors — psychological as well as physiological — play a role in producing and maintaining an erection. The pandemic has led to social isolation and a surge in anxiety and depression, all of which may play a role.
“Men’s erections are more complicated than people think,” Dr. Justin Dubin, who co-wrote a paper about the adverse impact of Covid on men’s health, said.
“You need good blood flow, you need the nerves to be firing, and you need good hormone levels, specifically testosterone,” he said. “But you also need to be in a good state of mind, and you also need to be aroused. If any of these things go wrong, you may have an issue getting an erection.”
In that sense, the pandemic is the perfect confluence of converging factors for causing erectile dysfunction, Dr. Joseph Katz, a professor at Florida College of Dentistry, said. Dr. Katz stumbled on the issue of erectile dysfunction while investigating Covid’s effects on oral health.
Some researchers speculate that erectile dysfunction may be linked to the well- documented loss of the ability to taste and smell experienced by Covid patients, because these senses play an important role in sexual arousal. “It is through smells that the arousal mechanism in the brain is ignited,” three Italian urologists wrote last year in a letter responding to Dr. Jannini’s paper.
At the very least, men need healthy blood vessels and good blood flow in order to develop and sustain erections. The coronavirus may damage blood vessels and the lining of the vessels, called the endothelium, as it binds to the molecular receptors that are plentiful on endothelial cells.
The vessels may not constrict and stretch as needed to allow for blood flow to the penis. Injury to the blood vessels may also contribute to more serious complications of Covid, like heart attacks, strokes and abnormal clotting.
“Our entire vascular system is connected — it’s not an isolated penis problem,” Dr. T. Mike Hsieh, director of the men’s health center at University of California, San Diego, said.
But vascular problems can manifest in the sexual organs first, because the vessels there are so small. (Dr. Jannini calls erectile dysfunction “the canary in the coal mine” for cardiovascular disease.) Erectile dysfunction and cardiovascular disease share risk factors — such as being severely overweight, having metabolic diseases like diabetes, smoking and older age — which also increase the odds of having severe Covid.
“The artery for the penis is one-tenth the size of a coronary artery, and when you have a narrower vessel, whether it’s a plumbing problem or a vascular problem, it will show up there first, even before you see it in a larger artery,” Dr. Hsieh said.
Erectile dysfunction can precede a heart attack by about five years, he said, and can be an early signal that there are other underlying risk factors.
“When I see a guy for erectile dysfunction, they don’t just get a Viagra or Cialis prescription,” Dr. Hsieh said. “They get a referral to a primary care colleague or a cardiologist to make sure their cholesterol is in check, their diabetes is under control, to discuss weight management, lifestyle or dietary changes.”
Erectile dysfunction may point the way to better diagnosis of long Covid, Dr. Jannini said, or even deteriorating mental health.
“If you have a patient who survived Covid, and you want to know if he has long Covid or not, just ask him how it’s going in bed,” Dr. Jannini said. “If he’s having a normal sex life, the possibility of him having serious long Covid is very, very low.”
Left untreated, erectile dysfunction can lead to further complications. Cases of Peyronie’s disease, a condition that causes curved, painful erections as a result of fibrous scar tissue built up in the penis, and orchitis, the inflammation of one or both of the testicles, have developed in men who have had Covid, according to published research.
Men who don’t have normal erections for several months at a time may develop scar tissue and fibrosis, which makes erectile dysfunction harder to treat and may even lead to shortening of the penis.
Erectile dysfunction can resolve on its own, but Dr. Hsieh encouraged men with symptoms to see their physicians, and sooner rather than later.
“If you’re having these problems, do not wait,” he said. “For the most part, we can get the guys’ sex lives back.”