New research has found that women are "significantly" more likely to suffer from long COVID syndrome compared to men.
The study, conducted by researchers from the Johnson & Johnson Office of the Chief Medical Officer Health of Women Team, found the odds of females developing long COVID is 22 per cent higher than males.
The findings were published Monday, in peer-reviewed journal Current Medical Research and Opinion.
Also known as post-acute COVID-19 syndrome, or PACS for short, long COVID occurs when symptoms linger at least four weeks after the initial recovery period, with some even lasting for months.
While understanding of long COVID is limited, the syndrome can be debilitating and is believed to affect between 10 per cent to one third of those who have been infected.
Previous studies have shown that women are less prone to developing severe disease than men in the acute phase of COVID-19, however, researchers note few studies have assessed sex-differences related to long COVID.
"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 study's authors wrote.
The latest study found that women with long COVID showed a variety of symptoms including respiratory issues of the ear, nose, and throat, mood and neurological disorders, skin rashes, musculoskeletal pain and fatigue, as well as gastrointestinal and rheumatic disorders.
In comparison, researchers found the men studied were more likely to experience endocrine disorders, such as diabetes and kidney problems.
The study's authors say the findings underscore a "critical need" for sex-disaggregated research, saying the difference in immune system function between females and male "could be an important driver" in developing long COVID.
"Females mount more rapid and robust innate and adaptive immune responses, which can protect them from initial infection and severity. However, this same difference can render females more vulnerable to prolonged autoimmune-related diseases," they wrote.
Researchers analyzed data from about 1.3 million patients compiled from previous studies published between Dec. 2019 and Aug. 2020 on COVID-19, as well as long COVID studies conducted from Jan. 2020 to June 2021.
Of the 640,634 total articles studied, researchers say only 35 provided enough sex-disaggregated data of COVID-19 to examine how females and males differently experience the disease.
While previous studies have looked at sex differences in hospitalizations, ICU admissions and deaths, researchers say the conditions caused by COVID-19 and its long-term impact on the body have been understudied when it comes to females and males.
The study authors note that sex differences in the outcomes of previous coronavirus outbreaks have been reported. Because of this they say the difference between women and men infected with COVID-19 "could have been anticipated."
"Unfortunately, most studies did not evaluate or report granular data by sex, which limited sex-specific clinical insights that may be impacting treatment," they wrote.
Researchers say they hope others build off their findings, looking at additional factors than may impact sex disaggregated data when it comes to COVID-19, such as gender-based disparities in access to care and employment. For example, the study noted that women may be at greater risk of exposure to the virus in certain professions, including nursing and education.
The study's authors say these factors "could affect the natural history of the disease, leading to more complications and sequela," thus more research is needed.
Researchers say having sex disaggregated data is "imperative if we are to ensure that disparate outcomes in disease course are addressed."