Covid-19 could have a long-term effect on male fertility, a study in Germany has claimed.
Scientists compared semen quality in groups of men who had recovered from the virus to those who had never contracted it.
They found that having had Covid-19 appeared to lead to ‘lower sperm quality and reduced fertility potential’.
The sperm were more likely to be deformed, the researchers found, to be less mobile and to be found in lower concentrations in the semen, which could make it more difficult to conceive.
Effects of Covid on people’s ability to have children has not been widely studied because the disease has more devastating effects on the lungs, heart and blood vessels which have required more urgent scientific attention.
It was not exactly clear how coronavirus affected the testicles, the scientists said, although fever – a common symptom of Covid – is known to be able to damage them.
The damage to sperm quality appeared to reduce after time, with it returning towards normal levels as more time elapsed after infection, but the effects were worse in men who had been more severely ill.
Following the study, researchers advised men who survived Covid to have their reproductive health checked before trying for a baby – but warned their findings were not concrete.
Experts at Justus-Liebig University in Giessen, Germany, analysed 84 men with Covid- 19 and 105 age-matched control subjects, without the virus, taking measurements every 10 days for 60 days.
The study found a significant deterioration in semen quality up to 60 days after the illness.
When they compared the two groups they found that indicators that could make a men less able to father a child were significantly more common among men who had had Covid.
These included signs of swelling, sperm cell death and oxidative stress, which is when volatile chemicals build up in living tissues because of cells not working properly.
The concentration of sperm was reduced by up to 516 per cent and its mobility dropped by 209 per cent, the study said, although all the men were still confirmed to be fertile.
The reduction in mobility and concentration of sperm, as well as a significant altering of their shape which is critical to their ability to move through the cervix and uterus, led to a state called OAT.
OAT is known scientifically as oligoasthenoteratozoospermia and is a common cause of low fertility among men.
The lead researcher on the study, PhD student Behzad Hajizadeh Maleki said: ‘These effects on sperm cells are associated with lower sperm quality and reduced fertility potential.
‘Although these effects tended to improve over time, they remained significantly and abnormally higher in the Covid-19 patients, and the magnitude of these changes were also related to disease severity.’
Although the Giessen team’s findings seem worrying, other scientists say they want more research and longer term evidence to be convinced about Covid’s real effects on fertility.
Male fertility is known to be affected by fevers because the testicles cannot function as well at high internal temperatures.
Fever is one of the most common symptoms of the coronavirus so this link could account for some of the damage seen in the team’s study. Often the damage is reversible and reduces over time.
Professor Alison Murdoch, a fertility expert at Newcastle University, said: ‘It is well documented that adverse changes are frequently seen after systemic illness with recovery typically taking at least 3 months.
‘As the authors acknowledge, their findings may be such a nonspecific response. Thus, longer term studies are needed before the testes is considered to be a high-risk organ specific to Covid-19.
‘It is important to note that there is no evidence of Covid-19 virus in the semen and that there is no evidence that virus can be transmitted via semen.’
Professor Allan Pacey, an expert in andrology at the University of Sheffield, also urged caution over the findings, saying: ‘Since sperm production takes just under three months, roughly, to be completed from start to finish, in my opinion they ended the study 30 days too soon.’
Another study found last year that Covid-19 may be able to deplete testosterone stores in the body, which could be expected to have an impact on male fertility, which is controlled by the sex hormone.
Researchers in Turkey analysed levels of the sex hormone in 200 men who were in hospital after they tested positive for Covid-19.
More than half (51 per cent) had developed a condition called hypogonadism, in which their bodies did not produce enough testosterone. On average, participants’ levels were drained by 30 per cent post-infection to borderline unhealthy levels.
Academics claimed there was a direct correlation between severe illness and lower testosterone levels.
But, even among men who showed no symptoms of the virus at all, two thirds reported having a lowered sex drive – a tell-tale sign of low testosterone.
As well as being key in the development of sex organs and muscle growth, testosterone also helps regulate the immune responses, including fighting viral infections.
Low levels have been linked to an increased risk of dying from the flu, as well as inflammation, heart disease and high blood pressure. (DailyMail)
