Omicron v Delta: Women more susceptible than men to long Covid

Women are more susceptible than men to long Covid, it has been revealed. Here’s what you need to know.

Women are far more likely than men to suffer from long Covid than males and will experience substantially different symptoms, according to a broad new research review.

Long Covid is a syndrome in which complications persist more than four weeks after the initial coronavirus infection, sometimes for many months.

The review, published in the peer-reviewed journal Current Medical Research and Opinion on Tuesday, included 1.3 million patients, and revealed women were 22 per cent more likely to develop persistent symptoms contracting Covid.

For women, lingering symptoms after a Covid infection included fatigue; ear, nose and throat issues; as well as mood disorders like depression. They also had respiratory symptoms, and neurological, skin, gastrointestinal and rheumatic disorders.

In contrast, men with long Covid were more likely to have endocrine disorders, including diabetes and kidney issues.

“Knowledge about fundamental sex differences underpinning the clinical manifestations, disease progression, and health outcomes of Covid-19 is crucial for the identification and rational design of effective therapies and public health interventions that are inclusive of and sensitive to the potential differential treatment needs of both sexes,” the authors said in a journal news release.

Shirley Sylvester, senior medical director for women’s health at Johnson & Johnson in New Brunswick, N.J., and her team of researchers noted that differences in how men’s and women’s immune systems function could be a key factor.

“Females mount more rapid and robust innate and adaptive immune responses, which can protect them from initial infection and severity,” Sylvester and colleagues wrote.

“However, this same difference can render females more vulnerable to prolonged autoimmune-related diseases.”

Covid-19 symptoms can sometimes persist for months. Picture: Supplied

Infection with the Omicron strain of Covid is less likely to lead to long Covid than the Delta strain, another study has found.

The researchers, who published their world-first findings in the medical journal The Lancet, revealed just under five per cent of people infected with Omicron went on to develop long Covid, compared to almost 11 per cent of Delta cases.

The Omicron variant spread quickly across the world after it was first detected in November, 2021. And while Omicron appears to cause less severe acute illness than previous variants, at least in vaccinated populations, the potential for people to experience long-term symptoms was a major concern, the researchers wrote.

“We believe this is the first peer-reviewed study to report on long Covid risk associated with infection by the Omicron variant, highlighting that health surveillance using smartphone apps can produce rapid insights, which we have consistently shown are accurate and subsequently replicated,” they wrote.

The researchers collected data from patients who had new or ongoing symptoms four weeks or more after the start of acute Covid-19 in the UK during the Omicron period and compared it with the Delta period. They used self-reported data from the UK’s Covid Symptom Study app

They identified 56,003 UK adults who first tested positive between December 20, 2021, and March 9, 2022, and satisfied the inclusion criteria for the Omicron strain.

Using identical selection criteria, 41,361 adult cases of the Delta were identified between June 1, 2021, and November 27, 2021.

Among Omicron cases, 2501 (4·5 per cent) of people experienced long Covid and, among Delta cases, 4469 (10·8 per cent) experienced long Covid.

Dr David Strain, Clinical Senior Lecturer and Honorary Consultant, University of Exeter Medical School, said the results were “very reassuring for people who caught Covid in that (the Omicron) period.” However he said it might not apply to all strains of the Omicron variant.

“It is important to say however that these data come from the omicron BA. 1 period,” he said.

“The Office for National Statistics suggested that the BA. 2 variant that has caused much of the recent wave, did cause long Covid in triple-vaccinated people at approximately the same rate as the Delta.”

Dr Strain said it was impossible to comment on the longer term impact of these variants as it was still early days.

“However even 4.4 per cent of the very large number who experienced Covid as protections were eased, creates a significant public health burden of this disease with no known treatment, or even reliable diagnostic test,” he said.