Are men who have had covid less fertile than others? According to a German study published on January 29, 2021 in the scientific journal Reproduction, the coronavirus could affect the quality of the semen of men who have contracted it. It remains to be seen if all men are affected, and for how long.

Twice the inflammation

The team of researchers from the Justus-Liebig University (Giessen, Germany) regularly analyzed the sperm of 84 men under the age of 40 for two months. They had all been infected with the coronavirus and the majority had declared a severe form of the disease. The researchers then compared their analyzes with those conducted on 105 men who had not contracted the disease.

As a result, in men with covid-19, markers of inflammation in sperm were twice as high as in men in the control group.

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Less mobile sperm

And that’s not all: the sperm concentration and their mobility were “significantly lessLikewise, the researchers counted significantly more sperm with an altered shape among participants with covid.

So many alterations that correspond to a state of “oligoasthenoteratospermia, which is one of the most common causes of subfertility in men“, worry the researchers.

These results constitute the first direct experimental evidence that the male reproductive system can be targeted and affected by covid-19“, they conclude.

Secondary inflammation

But how to explain these results? First of all, it is unlikely that the reproductive cells themselves will be affected by the virus, according to the first analyzes carried out. But the inflammation that the virus causes in the body, sometimes up to cytokine storm, could lead to inflammation of the testes. This is what a Chinese study explains, also published in Reproduction, which is interested in the theoretical impact of covid on male reproduction.

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It is this secondary inflammation that could be associated with oxidative stress, a disorder in particular deployed by the body to fight viruses. This condition would then have a negative impact on the formation of spermatozoa (spermatogenesis) and the production of hormones in the testes.

Fever and drugs also involved?

Regardless of the action of the coronavirus, “we already know that fever can have a negative impact on sperm production, regardless of the illness that caused it“, also notes to AFP Allan Pacey, specialist in male fertility at the University of Sheffield (United Kingdom).

Another possibility: it is not the virus itself but the treatments that have had an effect on the sperm. Thus, corticosteroids (received by 44% of the participants in the German study), and antivirals (received by 69%) are suspected of having a negative impact on the quality of sperm, remind the authors of the study.

“Do not be overly alarmed”

Men should not be overly alarmed“nonetheless reassures Alison Campbell, embryologist for the British group Care Fertility, which did not participate in the study.”There is currently no established evidence of long-term damage caused by covid-19 to semen or male reproductive potential.“, she told AFP.

Other longer-term studies on a larger number of patients are still necessary to confirm or not this observation.