My husband is worried he’s in a high risk category for succumbing to Covid-19. A former smoker who gave up for good during a nasty bout of pneumonia, he reckons his damaged lungs make him vulnerable. As it turns out, he might not be as vulnerable as he thinks – thanks to his willpower in kicking the smoking habit. Scientists have been working through data to understand how the coronavirus spreads, with a view to stopping it in its tracks, and have discovered that far more men die of Covid-19 than women. It’s not as simple as men and women having different chromosomes. Social aspects appear to play a part, not least of all that more men smoke – and smoking appears to facilitate a sneaky receptor in the lungs that picks up the coronavirus more easily. The Wall Street Journal picks up on what scientists are saying about why Covid-19 appears to be taking down more men than women. – Jackie Cameron
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Coronavirus seems to be infecting and killing more men than women
By Katie Camero
(The Wall Street Journal) – More infected men than women seem to be dying from the new coronavirus, according to data from countries hit by the pandemic, but an incomplete data set is clouding scientists’ ability to understand why.
The pattern underscores the role that sex – and the associated social norms and behaviours – plays as an indicator of risk and response to infection and disease.
“There are profound sex differences in immune systems, and this pandemic is revealing them once again,” said Marcia Stefanick, a professor of medicine at the Stanford Prevention Research Center, part of Stanford University School of Medicine. “What is biology versus what are our social norms and gender behaviors confounds our ability to understand what’s going on.”
In Italy, men comprised about 70% of the deaths from Covid-19—the illness caused by the new coronavirus—as of March 26, according to the country’s National Health Institute (ISS).
Men are also more likely to be infected by the virus, especially if they are older with underlying health conditions, scientists say. In China, several studies show men comprised more than half the infected patients since the first cases appeared in December.
Past transnational outbreaks of illnesses such as severe acute respiratory syndrome (SARS) in 2003 and Middle East respiratory syndrome (MERS) in 2012 also posed double the risk of death for men compared with women, studies showed.
Men across the globe are now considered three times more at risk of dying in a hospital from Covid-19, according to a meta-analysis done by researchers at the University of Miami Miller School of Medicine. The study, published by medRxiv – a site for non-peer reviewed papers – breaks down data published between Jan. 1 and March 3 on 4,789 patients.
One reason may be that social behaviors likely to increase chances of infection and death from the virus – such as smoking and alcohol consumption – are associated more with men. This could explain why they tend to suffer more than women from conditions such as lung cancer and heart attacks, according to a 2016 study published in the journal JAMA.
In Italy, more than 7 million smokers are men, while 4.5 million are women, according to ISS. In China, the prevalence of smoking among men is 10 times higher than among women, experts say.
What’s more, scientists say the prevalence of the receptor that helps the new coronavirus enter human cells is higher in smokers, which might explain why more men are taking a blow from a disease that largely affects the respiratory system.
“The thing is, more studies need to be done around the world,” said Sara Haddadi, co-author of the preprint in medRxiv and a clinical-research coordinator in the division of pulmonary and critical care at the University of Miami.
The Centers for Disease Control and Prevention didn’t comment.
Gender distribution in the workplace also plays a role. Some scientists in Wuhan, China, speculated the virus’s prevalence in men could be tied to their dominance in the labor trades, which likely brought them closer to the local market where the pathogen is thought to have jumped from one unidentified species to people.
Women also have more robust immune systems, Dr. Stefanick said, adding that they react better to vaccinations and can clear infections more easily than men.
Part of the reason being is that through pregnancy, women’s bodies have learned to attack invaders such as bacteria, viruses – and sperm. For nine months, a woman carries foreign DNA in her body and must protect it to produce life. “Evolution has been working this way for a long time, and it isn’t just in women, this is true of animals as well,” Dr. Stefanick said.
Sex chromosomes play a part, too, she said. Men have a pair comprising X and Y, while women have two X’s. The X, which has about 900 genes – many related to immune function – is about three times as large as the Y chromosome. “So females have double the doses” of those genes that can support their immune system, Dr. Stefanick said.
Researchers say the Covid-19 disparity raises questions about possible gender-related reactions to different treatments and the potential need for more aggressive treatment in men. Such would include earlier intubation and mechanical ventilation, though researchers say more data is needed to understand why.
Write to Katie Camero at [email protected]
