The novel coronavirus can persist in the semen of men who are recovering following infection, according to a new study.
The preliminary findings of a Chinese study raise the small possibility that the virus could be sexually transmitted.
'We found that SARS-CoV-2 can be present in the semen of patients with COVID-19, and SARS-CoV-2 may still be detected in the semen of recovering patients,' lead author Dr Diangeng Li of the Chinese People's Liberation Army General Hospital in Beijing wrote.
The study, conducted by researchers at the Shangqiu Municipal Hospital in Henan province, analysed the semen of patients hospitalised with the virus. Participants included men aged 15 years and older who tested positive for the coronavirus between 26 January and 16 February 2020.
Of the 38 men included in the study, 15 (39.5 percent) were in the acute stage of infection, whereas the rest had achieved clinical recovery. The semen of six patients (15.8 percent) tested positive for SARS-CoV-2, including four patients (26.7 percent) in the acute stage of infection, and two of the 23 (8.7 percent) who were recovering.
'Even if the virus cannot replicate in the male reproductive system, it may persist, possibly resulting from the privileged immunity of testes,' the team added, meaning that the immune system cannot fully reach the testes to target a viral infection.
However, experts in the field have stated that while the findings are interesting, they should be viewed with caution and in the context of other studies, such as the research performed by scientists at Tongji Medical College in Wuhan that found no evidence that the virus was present in the semen of 34 men.
Professor Allan Pacey, a leading expert in male fertility at the University of Sheffield, also revealed there are technical challenges in testing semen for viruses, and that it is unknown whether the presence of SARS-CoV-2 in semen can result in infection by sexual contact.
'However, we should not be surprised if the virus which causes COVID-19 is found in the semen of some men, since this has been shown with many other viruses such as Ebola and Zika,' he said.
Professor Sheena Lewis, emeritus professor of reproductive medicine at Queen's University Belfast, also stressed that this was a 'very small study' and that 'the long-term effects of SARS-CoV-2 on male reproduction are not yet known'.
The study was published in JAMA Network Open.