Women are much more likely than men to suffer from long Covid – where a host of debilitating symptoms last beyond four weeks, sometimes for more than a year. But the reason why this is the case hasn’t been made clear.
Data from the Office for National Statistics (ONS) has repeatedly shown women tend to fare less well than men. And now, two new studies have shed more light on the gender disparities between those blighted by long-term symptoms of the virus and those who recover fairly quickly.
The first looked at the long-term effects of Covid-19 after hospital admission – 327 patients were discharged and followed up on to see how they recovered. Women under 50 had higher odds of worse long-term health outcomes when compared to men and older study participants.
Dr Janet Scott, lead author of the pre-print study, from the University of Glasgow-MRC Centre for Virus Research, said the finding could have “profound implications” for pandemic policy decision, as well as vaccination strategy.
Females under the age of 50 were five times less likely to report feeling fully recovered. They were twice as likely to report worse fatigue, seven times more likely to be breathless and more likely to have worsening difficulties or new disabilities than men of the same age.
A separate pre-print study looking at the impact of coronavirus on physical and mental health in adults discharged from hospital after having Covid-19 also found women were more impacted.
Patients were assessed between two and seven months later to see how they’d recovered. Factors associated with failure to recover included: being female, middle-aged, white ethnicity, having two or more underlying health issues, and having more severe acute illness from Covid.
Gender differences have been apparent since the start of the pandemic, when men were found to have more severe outcomes from Covid-19. They’re more likely to be hospitalised by the virus and end up in intensive care, and also twice as likely to die from the virus as women.
“We’ve appreciated throughout that there are gender differences in immunity to this virus,” Professor Daniel Altmann, of the Department of Immunology and Inflammation at Imperial College London, tells HuffPost UK.
“In our data, women tend to have higher levels of antibody, while men tend to have higher levels of T-cell mediated immunity. As is now well appreciated, men tend to fare worse during severe, acute infection. That leaves the question of why women should be more susceptible to long Covid.”
The answer might lie in differences in how our immune systems work – or that’s what scientists hypothesise, anyway. Research is needed to look into this.
Dr Louise Newson, a GP and menopause specialist, previously said during a webinar that women have “a stronger response to infections, but especially to viruses, compared to men”. This is because women have different immune systems. She added that “frustratingly, so much research on immunity and in general is done in men and not in women”.
In a 2016 review on the differences in immune responses between males and females, professor Sabra Klein, of The Johns Hopkins Bloomberg School of Public Health, and professor Katie Flanagan, of Monash University, said females’ strong immune responses result in faster clearance of pathogens and greater vaccine efficacy compared to males. But it also contributes to females’ increased susceptibility to inflammatory and autoimmune diseases.
The sex hormone oestrogen could also play a role. A study by King’s College London (KCL) found post-menopausal women with lower levels of oestrogen appeared to be at higher risk of developing serious complications of Covid.
The hormone, which declines in women as they age, interacts with the immune system in various ways, including influencing how many immune cells are produced and how they respond to infection.
Prof Altmann and others are looking at underpinning immune mechanisms that might explain the differences in how people recover from the virus – including the role of sex hormones. He points out women are more impacted by autoimmune diseases such as lupus and multiple sclerosis, which was “always taken to indicate interaction between sex hormones and the immune system”.
The interaction between sex hormones and the immune system now needs to feed into our thinking about long Covid, adds Prof Altmann.