Do testicles make men more vulnerable to coronavirus? Study suggests testes harbour Covid-19 giving virus sanctuary from immune system

The testicles may harbour coronavirus and give it a sanctuary from the immune system which allows the infection to persist for longer in males, a study has suggested.

When Covid-19 enters the body it binds with cells expressing the ACE2 protein, or angiotensin converting enzyme 2. 

These are found in the lungs, heart and intestines. In men the protein is also found in large quantities in the testes whereas, in women, very small amounts are found in ovarian tissue.

Coronavirus is more likely to severely affect men than women. In the UK alone men are dying from the disease at twice the rate of women, according to the Office for National Statistics (ONS). Men had a mortality rate of 1,728.2 per 100,000, while women had a rate of 840.9 per 100,000.

The study, carried out by researchers in New York and Mumbai, followed 48 men and 20 women living in Mumbai who had been infected by coronavirus.

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While the women in the study took four days to clear the infection men took 50 per cent longer, needing six days.

In three families that took part in the study men also took longer than women to recover from coronavirus.

Participants were aged from three to 75 years old, with an average age of 37.

Dr Aditi Shastri, an oncologist at Montefiore Medical Center in the Bronx, carried out the study with her mother Jayanthi Shastri, a microbiologist at the Kasturba Hospital for Infectious Diseases in Mumbai.

Their work was released ahead of publication on medical website MedRxiv. It has not been peer reviewed.

Virology Professor Ian Jones at the University of Reading said the coronavirus would need to travel in the bloodstream to reach the testes, which is 'not generally' what the virus does.

'The main site of virus replication is the respiratory tract and to reach other sites the virus should have to travel in the bloodstream.

'This has been reported for the virus but it is not generally what coronaviruses do.

'Men generally do worse than women in immunological outcomes, possibly the result of only one X chromosome, and I think that this imbalance is more likely behind the differences seen. This work is not peer-reviewed.'

 Professor of Molecular Virology at the University of Nottingham Jonathan Ball said that a separate study had found no coronavirus in the semen of sufferers, suggesting it wasn't an 'important reservoir' for coronavirus. 

'In a different study, which again was a preprint and so not peer-reviewed, a small number of males had their semen tested for the presence of the coronavirus while they were recovering from the virus,' he said.

'There was also a sample of testes from another patient that had unfortunately died. 

'None of the samples tested positive for the presence of the virus, suggesting that the male genital tract wasn’t an important reservoir for the virus.'

Professor of Medical Imaging at University College London Derek Hill said that much more data was needed before any concrete conclusions could be drawn from the study. 

Coronavirus has also been reported to be a greater risk for older people, and particularly those more than 80 years old.