COVID-19 more deadly for men, finds global meta-analysis

The group of researchers, who usually specialise in understanding why autoimmune diseases like lupus are more common in women, reviewed existing data from 47 countries and 44 US states, which included more than three million cases of COVID-19.

Their findings, published today in the journal Nature Communications, support growing evidence that the disease COVID-19 may have more severe outcomes in men than women. Although the reasons for this remain untested, women are generally thought to have stronger immune responses to viral infections, which may help them to clear the infection more effectively.

“We found that roughly equal numbers of men and women were infected with coronavirus, but men had over two and a half times higher odds of needing intensive care and were 40 per cent more likely to die of COVID-19 than women,” says study co-author Dr Elizabeth C. Rosser, a Senior Research Fellow from UCL’s Centre for Adolescent Rheumatology Versus Arthritis, who is part-funded by the Medical Research Foundation.

“Our lupus research has shown that women tend to have a stronger immune response than men. Specifically, there are more immune-related genes on the X chromosome, which boosts the general response to infection, including boosting antibody production. Oestrogen could also be an important factor in boosting immunity.

“On the flip side this heightened response, when the immune system ends up attacking the body, is also what makes women more likely to develop autoimmune diseases like lupus, which is the focus of my own Foundation-funded work.”

Dr Elizabeth Rosser

Although the researchers could not gather consistent data on some important factors, including age, ethnicity, lifestyle and the existence of other underlying health problems, their study reveals an important trend in the epidemiology of COVID-19. Collecting this information alongside data on sex differences may reveal more about why COVID-19 leads to severe disease in some people and not in others.

Dr Rosser concludes: “Our study has important clinical implications for how COVID-19 is treated in men and women, as they are likely to respond differently. It also highlights the importance of recording and reporting the sex of Covid-19 patients in communities and hospitals, so that scientists can investigate patterns in data being collected across the world.”

This work was funded by a Centre of Excellence (Centre for Adolescent Rheumatology Versus Arthritis) grant, as well as grants from the Medical Research Foundation, Medical Research Council, NIHR, and the Great Ormond Street Hospital Children’s Charity (GOSH Charity).

Read the full Nature Communications research paper.

In her Foundation-funded project, Dr Rosser is looking at differences between young men and women with lupus, specifically in relation to the breakdown of cholesterol, and how this affects immune cell function. It is thought that sex hormones such as oestrogen may affect the onset and severity of lupus and might also explain why women are much more likely to develop the illness. Find out more.