By Professor Sabra Klein, from the Johns Hopkins Bloomberg School of Public Health
COVID-19, the respiratory illness that has become a world-wide pandemic, has been said to affect men and women differently. Men are thought to be more likely to become severely ill and die from the disease.
According to data from around the world, including China, Italy, the European Union and preliminary data from the UK, roughly an equal number of males and females contract the disease. However, in terms of severity, men fare worse than women. Data from Italy and China suggest that more men die from the disease, but it’s possible that this is because the groups of people in these groups are older. We do not yet know if this discrepancy holds up in the younger demographic.
To understand why males might be responding differently, we need to look at what happens when the virus enters our body. In order to survive, the virus needs to enter our cells where it can hijack our machinery to replicate. Once inside the cell, the virus tries to replicate itself. Estrogen in women is thought to make this harder, meaning that the virus can’t make as many copies of itself in women.
When the immune system realises the virus has infiltrated its cells, it launches an attack to try and clear out the infection. Generally speaking, women tend to mount a more robust immune response. This can be beneficial for initially recognising and initiating the clearance of a virus. However, in the long-term, if this is not properly regulated, you can get excessive immune responses. This can contribute to long-term inflammation and that in and of itself can cause some tissue damage.
In addition to these sex differences in physiology, there are also important behavioural differences. Men are less likely to go to hospital until later in their disease. However, as healthcare workers are often women, we may still see a shift away from the male bias of the disease as the pandemic progresses.