COVID is harming sperm, Israeli researchers say, raising infertility worries

Reviewing studies worldwide, experts see a 50% drop in sperm’s quantity and ability to move in patients who had moderate or serious coronavirus

Nathan Jeffay is The Times of Israel's health and science correspondent

3D illustration of sperm cells moving to the right towards an egg (Christoph Burgstedt via iStock by Getty Images)
3D illustration of sperm cells moving to the right towards an egg (Christoph Burgstedt via iStock by Getty Images)

COVID-19 is harming the sperm of patients, even weeks after recovery, Israeli doctors have concluded, raising concerns that the disease could reduce fertility.

“Men who had the mild disease had a broadly normal sperm quality,” Prof. Dan Aderka of Sheba Medical Center, told The Times of Israel this week. “But those who had the disease in moderate or serious form often didn’t, even after recovery.

“These men had a reduction of around 50% on average of the number of sperm per milliliter, total volume of ejaculate, and motility of sperm,” he said. This figure reflects testing that was carried out around a month after diagnosis.

Aderka, a Tel Aviv University professor, said he is concerned that a minority of men who had COVID-19 could face fertility problems or even “permanent sterility.” But he said that doctors need to monitor sperm of recovered patients for months to find out more — which is what he is planning to do.

An Israeli man is tested for coronavirus at a Maccabi Healthcare Services testing booth in the central city of Ramle on October 5, 2020. (Yossi Aloni/Flash90)

He drew his conclusions after conducting what is believed to be the most extensive analysis of the various research projects conducted around the world looking at sperm and COVID-19, in order to assess what is currently known. His analysis hasn’t yet been peer reviewed, but the 40-plus studies he referenced, covering the sperm of hundreds of men, have been.

Aderka is now starting to implement ongoing sperm monitoring for some recovered Sheba patients, to assess the long-term impact of the disease on male fertility.

He said: “We don’t know yet if these effects are reversible, but we do know that other diseases from the coronavirus family, such as mumps and SARS, have left a long term effect on fertility for male patients. For 20% of adult male mumps patients, there is sterility, total loss of fertility, so we know viruses can have such an impact.”

Professor Dan Aderka of Sheba Medical Center and Tel Aviv University (courtesy of Dan Aderka(

His concerns are based not only on the assessment of sperm samples but on reports of the state of testes of deceased COVID-19 patients. “A Chinese study examined coronavirus patients who died and found damage to the testes,” he said, adding that the damage was concentrated on two cells directly responsible for sperm production.”

He commented: “There is probably physical harm to the testes in some cases, though we don’t know in how many cases.”

He noted that the virus is found in the sperm of some patients during and after infection, but said this doesn’t mean it can be transmitted sexually and said all evidence currently suggests that it can’t.

He said existing literature suggests that the virus is found in the sperm of 13% of male patients who have the disease, and 8.6% of those who are recovering a week or two after the active disease. A month later, there are no traces of coronavirus ribonucleic acid (RNA) in the sperm.

Asked if there are any steps that men can take to protect their fertility during the pandemic he said that mask-wearing can help, even if one ultimately becomes infected.

This is because the viral load that enters the body tends to be smaller if people are protected by a mask, and the smaller the viral load, the better the immune system’s chances of beating the virus while still in the mild stage and having minimal impact on sperm.

Aderka said: “If you have a small viral load at the start, your immune system has a better chance of catching up with the virus, so wearing a mask can actually reduce severity, reduce mortality, and — potentially also, based on what we’re learning — reduce infertility.”

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