Men’s blood has higher levels than women’s of a key enzyme used by the new coronavirus to infect cells, the results of a big European study showed on Monday - a finding which may help explain why men are more vulnerable to infection with Covid-19.

Angiotensin-converting enzyme 2 (ACE2) is found in the heart, kidneys and other organs. In Covid-19, the respiratory disease caused by the novel coronavirus, it is thought to play a role in how the infection progresses into the lungs....