Men's blood contains higher levels of ACE2 (angiotensin-converting enzyme 2), which can help the virus attack healthy cells. A similar picture is seen in people on heart failure medication, which also increases ACE2 levels, and which makes the lungs more vulnerable.
ACE2 enzymes are receptors on the surface of cells that bind to the coronavirus and allow it to damage healthy cells, says Adrian Voors, at the University Medical Centre in Groningen, Holland. High levels of the enzyme are in our lungs, and this could explain why the virus can be lethal.
Men have much higher levels than women of ACE2 enzymes in their blood, the researchers discovered after taking blood samples from around 2500 men and 1000 women.
The enzymes are also found in the heart, kidneys and tissues lining blood vessels, and levels are also high in the testes.