Covid has been found in the testicles of infected men and could affect fertility as well as be sexually transmitted, scientists warned.
The widespread blood vessel dysfunction, known as endothelial dysfunction, that results from the Covid-19 infection could contribute to erectile dysfunction, according to scientists.
Endothelial dysfunction is a condition in which the lining of the small blood vessels of an organ fail to perform all of its functions normally meaning the tissues supplied by those vessels can become damaged.
Ranjith Ramasamy, a study author and associate professor and director at the University of Miami Miller School of Medicine's Reproductive Urology Program, said Covid can cause this problem in many organs - including the penis.
He added: "Our research shows that Covid-19 can cause widespread endothelial dysfunction in organ systems beyond the lungs and kidneys.
"The underlying endothelial dysfunction that happens because of Covid-19 can enter the endothelial cells and affect many organs, including the penis.
"In our pilot study, we found that men who previously did not complain of erectile dysfunction developed pretty severe erectile dysfunction after the onset of COVID-19 infection."
Dr Ramasamy and his colleagues collected penile tissue from two men with a history of Covid-19 infection who underwent penile prosthesis surgery.
One of the men was in hospital with Covid, while the other patient only had mild symptoms when he contracted the virus.
The researchers also gathered tissue from two other men with no history of having Covid-19 undergoing the same surgery for erectile dysfunction.
Investigators analysed all the tissue samples for evidence of the virus as well as endothelial dysfunction.
They found Covid was in the penile tissue of both men who had been infected, but not in the men with no history of the virus.
The men had been infected six and eight months before the study, the experts said.
These men had evidence of endothelial dysfunction, while the men who had been free of the virus did not, the researchers found.
Dr Ramasamy said: "This suggests that men who develop Covid-19 infection should be aware that erectile dysfunction could be an adverse effect of the virus, and they should go to a physician if they develop ED symptoms."
Similar to other Covid-related complications, the authors noted that widespread infection and subsequent endothelial dysfunction could result in erectile dysfunction, and that worsening of the condition could be due to the virus's presence in the penile tissue itself.
In a previous study published in the World Journal of Men's Health, Dr Ramasamy and Miller School colleagues found that the virus can also invade testis tissue in some men who are infected.
It was found that this might be the first step in understanding its potential impact on male fertility and whether Covid can be sexually transmitted.
First author Eliyahu Kresch, a medical student working with Dr Ramasamy, said: "These latest findings are yet another reason that we should all do our best to avoid Covid-19.
"We recommend vaccination and to try to stay safe in general."