No one is exactly sure why, but the coronavirus kills many more men than women. The death
rate for men with a coronavirus infection is much higher in Europe, China, the United States
and South Africa.
An explanation that has been widely considered is that the disparity is a result of life-style
choices. Men are more likely to smoke and drink alcohol – habits that would make them
more susceptible to respiratory diseases.
Dr Stanley Perlman of the University of Iowa argues that life-style choices might have an
impact, but that it is not the whole story. Testing how coronaviruses affect mice, he found
that at all ages, males were more likely to suffer from infection than females.
However, when he gave the female mice drugs that supressed the activity of estrogen, their
death rate shot up to the same level as the males. This suggests that estrogen offers some
protection against the virus.
Perlman believes that his experiments would apply to the new coronavirus as it infects
humans, but he admits that he is not sure how estrogen protects people.
A professor of immunology at the University of Oxford, Philip Goulder, said in a report
published on the BBC website, that “The immune response throughout life to vaccines and
infections is typically more aggressive and more effective in females compared to males”.
Women have two X chromosomes but men have only one and this is important as the X
chromosome senses and encodes the coronavirus. This means that women’s immune cells
have a better chance of recognising the virus and so the immune response to coronavirus is
amplified in females.