Testosterone could be the key reason why so many men are dying from coronavirus, doctors believe.
Twice as many males are succumbing to the disease as women in a pattern that has baffled scientists around the world.
Although theories put forward to explain the difference include men being more likely to smoke and the possibility of genetic differences that make their immune systems weaker than women’s, it could be simpler than that.
Prostate cancer experts have now uncovered intriguing clues that the sex hormone testosterone seems to play a crucial role by inadvertently helping the virus infect cells.
Italian medics discovered that prostate cancer patients given powerful drugs, known as androgen deprivation therapy, to radically cut testosterone levels were four times less likely to die of Covid-19 than those not on them.
Testosterone drives up levels of a protein called TMPRSS2, which is implicated in prostate cancer. But scientists have recently found that the coronavirus also uses this protein to ‘unlock’ cells.
Stock image: A man takes a Enzalutamide pill, which works by blocking the effect of testosterone on prostate cancer cells. Such treatments could be used to help coronavirus patients
Now medics at London’s Institute for Cancer Research are examining the link further, while counterparts at the University of California, Los Angeles, are looking at testosterone-blocking drugs as a potential Covid-19 therapy for patients in hospital. Professor Nick James, of London’s ICR, said it was ‘biologically plausible’ that testosterone made men more susceptible to the coronavirus.
He explained: ‘One of the proteins the virus appears to bind to in lungs is TMPRSS2. It’s a sort of lock and key thing: having bound to this protein, it provides the virus with a route into the cell.
‘You would therefore predict that men on treatments for prostate cancer that reduce their testosterone levels should be protected [from coronavirus] relative to men who are not on such treatments – meaning most men.’
Prof James is now looking at data from around 8,000 NHS prostate cancer patients in a trial he runs, to see if those on hormone reduction therapy have been less likely to be hospitalised with Covid-19.
Using such drugs as a coronavirus treatment is a possibility, he said, but not one to be taken lightly due to their serious side effects.
‘Being on these drugs is the male equivalent of going through the menopause,’ he said. As a result, using them as a large-scale preventative was a non-starter. ‘You would almost certainly cause more harm than good,’ he added.