A women looking at cells through a microscope

Insights into why more men than women are affected by the novel coronavirus

Published 09 April 2020

Women are dying less and have fewer complications from the new coronavirus disease than men. A similar pattern was observed during the SARS and MERS outbreaks, but there remains much to be understood as to why.

And with COVID-19 spreading around the globe, it’s important to ask: how can we keep women – who make up the majority of global healthcare providers and also primary caregivers – from taking the infection home to families?

Roche neuroscientist Antonella Santuccione Chadha explores how a focus on sex and gender differences in disease can help propel precision medicine forward. Together with her Women’s Brain Project colleagues, they study how gender impacts different diseases, including Alzheimer’s disease and dementia. Their goal is to better understand the differences between men and women in disease and drug response, and use that knowledge to power precision drugs that take unique biological makeups into account from trials through treatment.

So when the new coronavirus disease began to spread in China and beyond, Antonella and her colleagues realised that, like SARS and MERS, men were disproportionately impacted. They had more complications, and more men than women were dying from the disease.

A hallmark of the virus?

Antonella Santucchione Chadha
Antonella Santucchione Chadha, Global Medical Lead Partnership Alzheimer's Disease at Roche

“In China, it was obvious there was a clear difference in mortality between men and women with COVID-19” says Antonella, who is the Global Lead for Alzheimer's Disease Partnership at Roche. “Then it got confirmed in Italy, and unfortunately in Spain, in Germany, and even here in Switzerland, where data pointed to the same type of result.”

The majority of healthcare workers responding to the coronavirus crisis around the globe are women, figures show. “So you would have expected more mortality in women,” Antonella points out. “But no, even though they have higher exposure than men to infection, data show that women are dying less from the disease.”

In Italy, for example, 56% of all COVID-19 infection cases through 30 March were men. But among healthcare workers (who are majority women) the rate plummets to 34%.
 

Grim numbers

According to the data, 70% of those who died from COVID-19 in Italy were men (as of 26 March). The mortality rates among men in other countries are also higher: China 63.8%, South Korea 53.6%, Spain 64% and Germany 65%. In Spain, 61% of those hospitalised for the disease are men, and men make up 72% of ICU admissions.

For perspective, in the 2003 SARS outbreak in Hong Kong, nearly 22% of infected men died, compared to about 13% of women. In an analysis of MERS infections between 2017 and 2018, about 32% of men died compared to nearly 26% of women.

“It has never been carefully studied or taken into account,” Antonella says. “This is the first time that we can state that those sex and gender differences became obvious to the world, and this is a unique opportunity to push sex and gender personalised medicine forward.”

Hygiene, health or hormones?

While some wonder if women are simply more diligent hand washers than men, Antonella says that’s likely anecdotal or even stereotyping. Plus, among healthcare professionals, where hygiene standards are stringent across both groups, mortality is still higher in men.

“I believe there is more of a biological explanation behind it,” Antonella says.

Women have a stronger immune response, she explains. And literature has indicated that above the age of 65, the immune response changes drastically between men and women. Older men have a higher pro-inflammatory response, which results in a lower reaction against infection.

“So as the inflammation occurs in the lungs, it’s like a cascade that gets activated, and you have cytokines and interleukins – think of these as messenger proteins among cells – and they just ‘boom’ explode within the body. And that’s the problem, because then it becomes very dangerous for our body.”

Furthermore, Ace2 receptors tend to be much higher in men, and this may act as a pathway that allows the virus to more easily invade cells, Antonella says.

This is the first time that we can state that those sex and gender differences became obvious to the world, and this is a unique opportunity to push sex and gender personalised medicine forward.”
Antonella Santuccione Chadha Global Medical Director Alzheimer's Disease Partnership Lead in PD Medical Affairs at Roche, and co-founder of the Women’s Brain Project

Center of the family

One of the most overlooked aspects of gender in disease, including COVID-19 – is the nearly universal role of women at the center of families and networks, compounded by the fact that most healthcare workers are women.

I have lots of friends in Italy who are medical doctors and they have small daughters”, Antonella says. “And they say, ‘you know what, how can I go home to my five-year-old daughter and say don’t hug me?’ It’s almost impossible.”

It’s essential to have preventive measures in place so women healthcare workers do not go home after caring for sick patients and become the carrier or the spreader of infection in their community, Antonella says. Some countries, such as Switzerland and Germany, immediately provided women who work in healthcare with assistance to help take care of their family and children. They also check on a daily basis for possible infections among healthcare professionals, trying to minimize the risk of spreading the contagion within their family, patients and communities.

All of these facets show the urgency to act to understand why sex and gender differences are important for developing drugs and developing preventive measures, for COVID-19 as well as other diseases, Antonella concludes.

Tags: Science, Society, Neuroscience, We are Roche