LONDON 10 Apr (ANA) - As the global death toll from the novel coronavirus mounts, evidence is growing that more men than women are becoming seriously ill — and dying — from the virus. In New York state as of April 9, for example, more than 60 percent of over 6,200 total deaths have been men. 

From the early days of the first coronavirus outbreak in China, men were turning up severely ill at a higher rate than women. And this pattern seems to be largely repeating itself — if in slightly different numbers — in country after country. 

Researchers are still not entirely sure why this is. But there are already some intriguing clues.

Could it be higher rates of smoking among men? A higher likelihood of delaying medical care? Or do the answers lie among the genes and sex hormones in our bodies that are setting men on a riskier course if they encounter the virus? 

As Marcia Stefanick, a professor of medicine at Stanford University School of Medicine, told the Wall Street Journal, “There are profound sex differences in immune systems, and this pandemic is revealing them.” But, she noted, “What is biology versus what are our social norms and gender behaviors confounds our ability to understand what’s going on.” 

Finding answers could help develop more effective treatment protocols and prevention measures, as well as lead to a more successful vaccine.

One key piece of context for these questions is that there are, in general, a variety of key biological differences in the way men and women fight off infections. Women, for example, tend to mount a stronger immune response. Researchers think this is in part because most women have two X chromosomes, and the X chromosome happens to contain most of the genes related to the immune system (and those with two X chromosomes instead of one also have a wider diversity of immune responses). This extra immune functioning, however, also seems to put women more at risk for autoimmune diseases, such as rheumatoid arthritis and Crohn’s disease. 

Hormones might also help provide women with a more effective defense. Some important immune cells have estrogen receptors, and an estrogen supplement has been shown to increase general immune responses in mice. 

A 2017 study in the Journal of Immunology specifically looked into sex differences from the coronavirus that causes SARS (which seems to have killed more men than women during an outbreak in 2003). In that study, researchers found that male mice were more susceptible to the virus. But when they blocked estrogen from working normally in the female mice, the females fell ill at higher rates. 

Women might also be more likely to launch an earlier attack on infections in general, saving the body from needing to use all of its virus-fighting might later— an event that can skyrocket inflammation and often do more damage to key organs. 

These sex patterns are not universal among infections. And data from other viruses, including influenza, sometimes even skews in the other direction, with more women dying than men. There’s still a lot to learn about the novel coronavirus, and so far there aren’t any studies on it looking specifically at these biological factors. We don’t yet know how these biological differences play out for Covid-19, if they do at all. But they’re definitely possibilities.(ANA)

FA/ANA/10 April 2020--------