It has been said that Covid-19 discriminates by age and by underlying health conditions.
But it has become increasingly apparent that it also discriminates by sex, with men more likely to test positive and more likely to die from the disease.
The trend was first seen in China, where one analysis found a fatality rate of 2.8% in men compared with 1.7% in women.
Since then, the pattern has been mirrored in France, Germany, Iran, Italy, South Korea and Spain.
In Italy, men have accounted for 71% of deaths and, in Spain, data released on Thursday suggests twice as many men as women have died.
So why are men more vulnerable?
“The honest answer is none of us know what’s causing the difference,” said Prof Sarah Hawkes, director of the UCL Centre for Gender and Global Health.
Early on, smoking was suggested as a likely explanation. In China, nearly 50% of men but only about 2% of women smoke, and so underlying differences in lung health were assumed to contribute to men suffering worse symptoms and outcomes.
The smoking hypothesis was backed by a paper, published last month, that found smokers made up about 12% of those with less severe symptoms, but 26% of those who ended up in intensive care or died.
Smoking might also act as an avenue for getting infected in the first place: smokers touch their lips more and may share contaminated cigarettes.
Behavioural patterns that differ from men to women is also a reason for this. Some studies have shown that men are less likely to wash their hands, less likely to use soap, less likely to seek medical care and more likely to ignore public health advice. These are the reasons that the men are at greater risk.
Let’s all take care and maintain good hygiene to fight COVID’19