This is why more men than women are dying of Covid-19

Scientists may have cracked the code as to why more men than women are dying of Covid-19, and it comes down to higher concentrations of a certain enzyme in their blood.

The enzyme is called angiotensin-converting enzyme (or ACE2), and heart researchers have found that the novel coronavirus uses it to attack healthy cells.

ACE2 sits on the outside of the cells that Covid-19 attacks, and it acts as a receptor which enables the virus to get in.

It exists in tissues through the human body, including the heart, kidney, veins and lungs, but is found in particularly high levels in the testes.

The study was done in different locations in Europe, and included several thousand patients.

It was published on Monday in the European Heart Journal, and included Norway and the Netherlands among others.

According to the World Journal of Emergency Medicine, men are generally more susceptible to coronaviruses, and this was evident in both the SARS and the MERS outbreaks.

According to Live Science, “even the comically labelled 'man flu' is so named because men tend to have a weaker immune system to respiratory viruses that cause flu and the common cold”.

Cardiology professor Adriaan Voors at the University Medical Center Groningen (The Netherlands), who led the study, said: “ACE2 is a receptor on the surface of cells. It binds to the coronavirus and allows it to enter and infect healthy cells after it has been modified by another protein on the surface of the cell ... High levels of ACE2 are present in the lungs and, therefore, it is thought to play a crucial role in the progression of lung disorders related to Covid-19.”

Prof Voors and his colleagues were already studying differences in markers of disease in the blood between men and women before the coronavirus outbreak. The results became available soon after the pandemic began.

Though more research is needed, this is a major breakthrough as scientists have been grappling with this issue ever since Covid-19 starting spreading through the Chinese city of Wuhan before being exported by its human hosts across the world.

Every study has found the same thing: men infected with the virus are getting sicker than women and more men are dying. 

In Wuhan, in the early days of the pandemic, it was found that up to 67% of hospitalised patients were male. Epidemiologists began to wonder if gender-specific lifestyle factors were at play (for example, more Chinese men smoke than do women).

But even in places with far fewer gender-specific behaviours to possibly explain the difference, similar patterns keep turning up: One study, published in the Journal of the American Medical Association, found that men made up more than 60% of patients admitted to hospital with the virus in New York City. Of those who ended up in intensive care, almost 67% were men.

The same study found that “mortality rates were higher for male patients compared with female patients, at every 10-year age interval older than 20 years”.

In Italy, up to 58% of those hospitalised were men, and it has also been found that men make up more than 60% of all Covid-related deaths across the globe.