The research team said Covid-19 could be seeded to the male reproductive tract, especially where there is local inflammation.
“Even if the virus cannot replicate in the male reproductive system it may persist, possibly resulting from the privileged immunity of testes,” they said.
Other experts have pointed out that the study, comprising 38 patients, is relatively small, and that only six of these patients had tested positive for the virus in their semen. Until now, researchers had previously found only 27 viruses in human semen.
It is not known whether the presence of Covid-19 in the testes affects men’s reproductive capability.
Professor Richard Sharpe, from the MRC Centre for Reproductive Health at the University of Edinburgh, said: “As the authors point out, this finding raises the possibility that Covid-19 might also be transmissible via semen – and thus via sexual contact – perhaps including during the recovery phase, which would have disease management implications.
“Whilst this is a small study, that leaves many important questions unanswered – how long after Covid-19 infection does detectable virus persist in semen in those with a semen-positive result?
“It suggests that obtaining answers to such questions should be an additional priority considering our global need to understand the dynamics of person-to-person transmission of Covid-19.”
So far, the means of transmission focused on by scientists is via droplets coming out of infected people’s noses and mouths and entering bodies of other people via their mouths, noses or eyes.