Gender difference in COVID 19
Since the beginning of pandemic, it has been noted that men tend to be more susceptible to infection, and the severity of their disease is much more. Though many recent studies have shown that women are infected as frequently as men, but it is the severity of disease in men which is perplexing.
It is commonly known that men have a higher incidence of co-morbidities like Hypertension, Diabetes and Heart disease. Also, there is an increase trend towards smoking, also, possibly, men seek medical attention much later as compared to women. While these common observations do help in understanding the incidence of infection, it does not explain the severity. The data from India also shows that there is almost 65%:35% ratio (Male: Female) death rate disparity due to COVID-19.
Medically there are various theories which have been discussed to be the reason for this gender bias; the three top theories being (1) Angiotensin Converting Enzyme-2 (ACE-2) receptor, (2) Oestrogen &Testosterone which affects the immune system and (3) genetic predisposition. Let’s understand these better:
– ATTACHMENT TO ACE-2 RECEPTORS:
It is now clearly understood that the ‘spike protein’ on the corona viruses like COVID, SARS (Severe Acute Respiratory Syndrome), MERS (Middle East Respiratory Syndrome) have an affinity for the ACE-2 receptors; it is almost like the ACE-2 receptor is the gateway for these viruses. The concentration of ACE-2 receptors is present in abundance in males as compared to females. They are found in high concentration in the Lungs, Heart, Intestine and Gonads.
– UNDERSTANDING THE OESTROGEN AND TESTOSTERONE CONNECTION:
Female is a stronger sex with respect to immune response and resilience. The female hormone Oestrogen stimulates the immune response rapidly and also supresses COVID-19 virus replication. Whereas the male hormone Testosterone inhibits the body’s own immune response, hence making males more prone to severe infection. This quality of Oestrogen is not only seen in COVID -19 cases, but also in other viral illnesses like Influenza.
– THE GENETIC PREDISPOSITION:
The possible third reason for this phenomenon is that the genes which are responsible for identifying a pathogen in body and mount a response to them, are present on the X chromosome. Since females have 2 X chromosomes, they are more likely to have a rapid immune response to a pathogen and offer better protection. On the other hand, because of Oestrogen and rapid response to immune system, women tend to have more auto immune problems as compared to men!
In a recent Sero survey conducted in city of Mumbai, it was found that more women had developed antibodies to COVID-19, which affirms the fact that women probably had a very minor illness which went un-noticed as compared to men, hence while more men went on to develop symptoms, women probably remained largely protected due to their immune response.