While a majority of the infections result in asymptomatic cases, mild or moderate infection, a significant minority develops severe and even critical infection.

According to the Chinese scientists analyzed the output of 48 patients who had caught the illness — 18 who were still in hospital and 26 who had recovered already.

About 13% to 19% will need mechanical ventilation, and about 5% may die rather than recover from lung injury and accompanying multi testicle organ dysfunction.

Scientists say it suggests the bug can persist much longer in the testicles and could be spread later through sex.

Writing in the journal JAMA Network Open website, researcher Dr Shixi Zhang, from the Shangqiu Municipal Hospital, says “the survival of SARS-CoV-2 in a recovering patient’s semen maintains the likelihood to infect others and large testicle expansion”.

He added if bigger trials show coronavirus is passed on during sex, the recovering men should be encouraged to “abstain or use condoms” to prevent transmission.

Scientists have provided evidence Covid-19 could have significant fertility implications, in a study lead by Assam University and published by the Royal Society.

The study explains: “This may pose a global threat to male fertility potential, as men are more prone to SARS-CoV-2 infection than women, especially those of reproductive age.

Despite the lack of direct viral injury to the sperm-containing cells, the damage to the Sertoli cells and androgen-producing Leydig cells can cause the seminiferous tubules to atrophy, and eventually, cause reduced or no sperm formation in recovered COVID-19 patients.

The researchers comment: ”Our findings suggest that studies should be undertaken to find ways to mitigate the risk of testicular injury during the COVID-19 disease course. These findings can provide evidence-based guidance for sperm donation and inform management strategies to mitigate the risk of testicular injury during the COVID-19 disease course.”