Men suffer a long-term drop in semen quality after COVID-19 – even if the infection was mild, reveals new research.
Scientists found that more than three months after suffering from mild COVID-19 infection, men have lower sperm concentrations and fewer sperm that are able to swim.
Professor Rocio Núñez-Calonge said that after an average of 100 days following infection there appeared to be no improvement in sperm quality and concentration, even though new sperm would have been produced in that time.
“There have been previous studies that show semen quality is affected in the short term following a COVID infection but, as far as we are aware, none that have followed men for a longer period of time,” said Nunez-Calonge about following effects of COVID.
Núñez-Calonge and her colleagues had observed that, in some men attending clinics in Spain for assisted reproduction treatment, semen quality was worse after COVID-19 infection than before the infection – even though they had recovered, and the infection was mild.
They decided to investigate if COVID-19 had influenced the decline in quality.
“Since it takes approximately 78 days to create new sperm, it seemed appropriate to evaluate semen quality at least three months after recovery from COVID,” said Núñez-Calonge in the effects of COVID-19.
Between February 2020 and October 2022, the research team recruited 45 men attending six reproductive clinics in Spain for the study. All had a confirmed diagnosis of mild COVID-19, and the clinics had data from the analysis of semen samples taken before the men were infected.
Another semen sample was taken between 17 and 516 days after infection. The average age of the men was 31, and the amount of time that elapsed between the pre-and post-COVID samples was a median of 238 days.
The researchers analyzed all the samples taken up to 100 days after infection and then analyzed a subset of samples taken more than 100 days later.
They found a “statistically significant difference” in semen volume (down 20 percent), sperm concentration (down 26.5 percent), sperm count (down 37.5 percent, total motility – being able to move and swim forwards (down 9.1 percent) and numbers of live sperm (down five percent).
Núñez-Calonge said motility and the total sperm count were the most severely affected.
Half of the men had total sperm counts that were 57 percent lower after COVID compared to their pre-COVID samples. The shape of the sperm was not significantly affected.
When the researchers looked at the group of men who provided a sample later than 100 days after COVID, they found that sperm concentration and motility had still not improved over time.
“The continuing effect of COVID infection on semen quality in this later period may be caused by permanent damage due to the virus, even in mild infection,” said Núñez-Calonge. “We believe clinicians should be aware of the damaging effects of SARS-CoV-2 virus on male fertility.”
It was already known that the SARS-CoV-2 virus can affect the testicles and sperm, but the mechanism is still not understood.
Núñez-Colange says that inflammation and damage to the immune system that is seen in patients with long COVID-19 might be involved.
“The inflammatory process can destroy germ cells by infiltrating the white blood cells involved in the immune system, and reduce testosterone levels by affecting the interstitial cells that produce the male hormone,” said Núñez-Calonge about the process of long COVID-19 “It should be mentioned that impairment of semen parameters may not be due to a direct effect of the SARS-CoV-2 virus.”
The research team plan to continue to study the men to measure both semen quality and hormonal status over a longer period.
They believe there should be more research into the reproductive functions of men after COVID infection to see if their fertility is affected temporarily or permanently.
The findings were presented at the 39th annual meeting of the European Society of Human Reproduction and Embryology (ESHRE) in Copenhagen, Denmark.
ESHRE chair, Professor Carlos Calhaz-Jorge, of the Northern Lisbon Hospital Centre and the Hospital de Santa Maria in Portugal), welcomed the findings.
“This is interesting research by Núñez-Calonge and her colleagues and shows the importance of long-term follow-up of fertility patients after a COVID infection, even if it’s a mild infection,” said Calhaz-Jorge. “However, it’s important to note that the semen quality in these patients after a COVID infection is still within the World Health Organization’s’ criteria for ‘normal’ semen and sperm.”
Produced in association with SWNS Talker