A study has found that men’s sperm cannot be harmed by Covid-19 vaccines, in research that should erase fears for male fertility.
The research, first reported by CNN on Thursday, found that here were “no changes” in men’s sperm after both doses of a Covid vaccine.
All 45 participants were screened to check they did not have any fertility issues, it was reported.
All men received doses of an mRNA vaccine – thought to be the American manufactured Moderna or Pfizer – for both doses.
Researchers took semen samples before the first shot, and 70 days after a second dose, to assess the sperm for changes in volume, concentration, motility and total sperm count.
Dr Ranjith Ramasamy, of the University of Miami Health System and author of the study, told CNN: “We found no changes in sperm parameters in the young healthy men that we studied who received both doses of mRNA vaccine”.
He added that studies were need to study non-mRNA vaccines, including Johnson & Johnson and AstraZeneca, but that both were “fairly similar”.
"We think the mechanism of how these vaccines work is all fairly similar despite different genetic material, so based on biology, we don't think there should be anything different with the other two vaccines," Dr Ramasamy said.
The findings follow a study in January that warned of reduced sperm counts from the Covid-19 virus itself, CNN reported, although scientists say further studies are required.
Health issues including obesity and everyday medication are also causes of reduced male fertility.