The level of a key enzyme used by the new coronavirus to infect cells is higher in men’s blood than women’s, a new study has found.
In most countries, the number of deaths from the new coronavirus among men is higher than women.
The discrepancy was first noted in China where the death rates showed that 2.8 percent of men who caught the virus had died, compared with 1.7 percent of women.
Italian women died at a death rate of 4.1 percent compared with 7.2 percent for men.
In South Korea, about 54 percent of the reported deaths were among men.
The study, published on Monday by the European Heart Journal, suggests that the Angiotensin-converting enzyme 2 (ACE2), a key receptor on the surface of cells which binds to the coronavirus and allows it to enter and infect cells, is more diffused in men than women.
Scientists measured ACE2 concentrations in blood samples taken from more than 3,500 heart failure patients, both men and women, from 11 European countries.
The study started before the coronavirus outbreak and did not include patients with COVID-19, explained Adriaan Voors, a professor of cardiology at the University Medical Center (UMC) Groningen in The Netherlands, which co-led the study.
But when other research began to point to ACE2 as key to the way the new coronavirus gets into cells, Voors and his team saw important overlaps with their study.
The journal’s findings come on top of numerous researches and studies that are trying to explain why men so far seemed more vulnerable to COVID-19, the disease caused by the new coronavirus, compared with women.
While so far there has not been an exhaustive response, doctors suggest that the answer lies in the combination of behavioural, immunological, hormonal and genetic factors.
Data collected so far has shown that people consuming more alcohol and tobacco are likely going to suffer to a greater extent the effect of the coronavirus disease. Data gathered in 2015 by the World Health Organization (WHO) shows that men drink about five times more alcohol than women. Men are also nearly five times as likely to smoke as women.
Another reason that women’s immune systems may function differently is because of the extra X chromosome that women have.
Women have two X chromosomes (XX) while men only have one (XY), and this is considered relevant to the immune response because a significant number of genes that regulate our immune response are coded on the X chromosome.