Why does Covid-19 hit men harder than women? The immune system reveals some clues

  • Men appear to experience Covid-19 more severely than women
  • Several studies have shown that Covid-19 deaths occur more frequently in men
  • New research analysed the immune response of both sexes to find clues 

One of the things that researchers are observing in Covid-19 is that it seems to affect men more severely than women. There are several theories, including research suggesting that oestrogen may protect women against Covid-19.

A team of researchers recently analysed factors like viral loads, antibodies and immune response in both sexes to find clues as to why men seem to be more susceptible to Covid-19.

Key differences in immune response

The team investigated SARS-CoV-2 in Covid-19 positive patients in the Yale-New Haven Hospital between 18 March and 9 May 2020.

They made use of several samples including blood, nasal swabs, saliva, urine and stool in order to isolate the virus and determine the viral load, as well as antibodies.

The team also performed two sets of data analysis to determine if there were any immune differences between the sexes. Their results, published in the journal Nature, reveal that the men and women showed different immune responses, affecting Covid-19 outcomes.

First of all, the analyses showed that levels of certain chemokines and cytokines were higher in males, which could explain severe Covid-19 symptoms in line with the so-called cytokine storm phenomenon in some patients.

The researchers also found that females tended to produce more disease-fighting T-cells, leading to milder Covid-19 symptoms. In older male patients, T-cell levels appeared to decline even further – but not in female patients.

Lifestyle factors in men seem to matter more

The researchers also looked at various correlations between age, body mass index (BMI) and the different viral loads and immune responses produced.

While age and BMI seemed to clearly impact the severity of Covid-19 in men, as well as the level of disease-fighting T-cells, the correlation wasn’t as strong in women.

Clues to treatment methods

The researchers stated that this study could offer a strong basis for further investigation into how Covid-19 affects the individual sexes, but also mentioned that study limitations should be taken into account.

They added that any vaccines and therapies that will help elevate a T-cell immune response would be more beneficial for men, while female patients would benefit from any therapies that help suppress the innate immune response (such as cytokines).

While there is still more to be unpacked about Covid-19’s effect on males versus females, this study shows a clear difference in immune response, which could be used in future vaccine development and treatment plans.

READ | Covid-19 continues to strike men harder than women

READ | Covid-19: Understanding immunity and what it means for a vaccine 

READ | How effective should a Covid-19 vaccine be for the world to return 'back to normal'? 

Image credit: Getty Images

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