Men are more likely to die of coronavirus than women, even when women catch it more often. This might be why

The immune systems of women and men respond differently to viruses

In August 2019, I had the opportunity to discuss the importance of gendered innovation for the space program during the National Space Council meeting. That meeting was chaired by Vice President Mike Pence, who is now leading the coronavirus task force. I was invited to address the need for gendered innovation for space exploration. I began my remarks with the following statement:

“Gender and sex impact every aspect of our lives on Earth and in space. It is more than spacesuits not fitting female astronauts. We see the impact from the shoes and clothing we wear, the electronic devices we use, the cars we drive in, and even the medications we take. Modifying appearances or the ‘pink it or shrink it’ approach for gender innovation will never work in any environment including space, battlefields, hot zones and in our homes.”

This statement highlighted why it is also important to have personal protective equipment (PPE) designed to fit the needs of women in order to prevent them from getting infected during outbreaks.

As Covid-19 has spread across the globe, we are learning that although women are getting infected, and in some locations at higher rates than men, their mortality rates may be half that of men, at any age level, in any geographic region. Since we no longer have the gift of time to develop PPE designed to meet the needs of women as we are struggling to just find PPE for anyone, it’s important to understand why there are differences in mortality rates among men and women.

First, the immune systems between men and women respond differently to pathogens. In general, women are more resistant to infection, but once infected, they mount vigorous responses which may be protecting them.

We see how these sex differences in immune response can, at times, be deleterious to women in that women are 80 per cent more likely than men to develop autoimmune diseases. Additionally, women can develop overproduction of inflammatory cells during infection which can be seen with influenza infections resulting in a “cytokine storm”. This is an overreactive immune response which results in the lungs filling with fluid and pus and the potential development of Acute Respiratory Distress Syndrome (ARDS). It can be fatal.

Hence, there is a sweet spot between protection and over-defense which may be one reason why women have lower mortality rates during this outbreak. This modulation of immune response may be key to why women are surviving this infection.

Of concern is that pregnant women may still be resistant to infections but may not mount the same vigorous responses as the body adapts to not reject the fetus. Additionally, as the fetus grows, there may be a restriction on breathing since it may be harder to take deep breaths. Pregnant women had higher morbidity and mortality rates during the H1N1 Influenza (swine flu) pandemic in 2009 to 2010. There are now studies to see if this pattern develops during a coronavirus pandemic. Small studies have not shown a negative impact at this time.

Furthermore, it is important to look at the impact of gender and risk factors on health outcomes such as smoking and vaping (including nicotine and cannabis) as well as when healthcare is delivered and whether men may present with more advanced disease. In most countries, men are more likely to smoke, and it’s possible that men may also leave it longer to seek help when they are severely ill.

Understanding how men and women develop immune responses will be important to saving lives. On the positive side, perhaps sex differences in female immune response may enable women and girls to receive smaller amounts of vaccines and other therapeutics which will enable more to be available to the world.

Dr Saralyn Mark, MD, is the former SR Medical/Policy Advisor to the White House, NASA and HHS. She is also the Founder/President of the nonprofit, iGIANT® (impact of Gender/Sex on Innovation and Novel Technologies) and author of ‘Stellar Medicine: A Journey Through the Universe of Women’s Health’