Coronavirus has infected more men than women, why?

According to a report prepared by the Chinese National Health Commission (NHC), about 80% of the more than 2,000 people who have died since the outbreak of the Coronavirus are people 60 years of age or older, and 75% had previous illnesses, such as diabetes.

Recently, several studies have indicated that men are more likely to die of the virus than women and represent a slight majority of cases. For example, in a Lancet medical study published last month, at least two thirds (68%) of 99 infected patients admitted to a Wuhan, China, hospital were men, with the average age of 55.5 years.   

Also, in a study published this month in the Jama Network, of nearly 140 coronavirus patients at a Wuhan University hospital, it was found that the virus was most likely to affect older men with preexisting health problems.

This data has led some researchers to suspect that certain biological factor might make men more susceptible to the virus.

In a column in the Financial Times, science writer Anjana Ahuja said that reasons for the discrepancy could be due to smoking, a variation of hospital treatment, and hormonal differences that could affect men’s immune system response to the disease.

Also, women are prone to autoimmune diseases, which causes parts of their immune system to become stronger to compensate. That could result in a stronger response to the coronavirus outbreak. 

The Lancet study previously mentioned also suggests that women may be less susceptible to coronavirus because their X chromosome and sex hormones such as estrogen may keep the virus from spreading widely throughout the female body. These hormones “play an important role in innate and adaptive immunity”, it said.

Also read: 'Chinophobia' spreads as fast as the coronavirus does

The New York Times, citing a study published in the Annals of Internal Medicine, which analyzes the deaths they experienced in the world in previous epidemics, such as SARS and MERS, also gives an answer on this topic. 

As read on their site, in 2003, more women than men were infected with SARS, but the mortality rate was higher in them. The same happened with the MERS, since about 32% of the patients ended up dying, a percentage higher by almost 8 points compared to women (25.8%).

There are different factors for which this phenomenon occurs, but mainly because the body of men tends to generate a weaker immune response against infections.

"This is a pattern we have seen in many viral respiratory tract infections: men can have worse results," Sabra Klein, a scientist at the Bloomberg School of Public Health at Johns Hopkins University, told The New York Times. "We have seen this with other viruses. Women fight better against them."

Smoking could have a lot to do

As read on Business Insider, smoking could be one of the answers on why the virus has affected more men. According to a 2010 national survey of smoking in China found that 62% of Chinese men had been smokers at some point, while only 3% of Chinese women had ever smoked. 

The executive director of the World Heath Organization's Health Emergencies Program, Michael Ryan, said smoking was "an excellent hypothesis" to answer this question. "There is a marked difference between male and females in this outbreak in terms of severity. And there's certainly a marked difference in those habits in China," Ryan said. "I think it should be relatively straightforward to establish the science."

"Since COVID-19 is a respiratory disease and often causes pneumonia, having a history of smoking could increase the risk of more severe respiratory distress or pneumonia," Saskia Popescu, an epidemiologist at the Honor Health medical group in Arizona, told Business Insider