Two studies published today in European respiratory diary report the results of a long COVID study, one showing signs of autoimmune disease in 41% of blood samples taken one year after recovery, and the other showing that 23% of patients were still exercise intolerance one year after discharge from hospital.
41% had symptoms of an autoimmune disease after 1 year
In the first study, a team led by researchers at McMaster University in Canada obtained blood samples from 106 people who tested positive for COVID-19 between August 2020 and September 2021. They also asked participants about symptoms of long-term COVID in period 3, 6 and 12 months. after recovery.
Twenty-two healthy volunteers and 34 who recovered from non-COVID respiratory infections were used as comparison groups.
After 3 and 6 months, nearly 80% of COVID-19 survivors had at least two antibodies that target healthy cells and tissues and contribute to autoimmune disease, dropping to 41% after 1 year. By comparison, most healthy volunteers had no evidence of these antibodies, while those who recovered from a disease other than COVID had relatively low levels.
Between 21% and 30% of COVID-19 patients – the majority who still had shortness of breath and fatigue – had specific antibodies (called anti-U1-snRNP and anti-SS-B / La autoantibodies) and inflammatory proteins (TNFα cytokines) after 1 year.
Autoimmune disease occurs when the immune system mistakenly attacks healthy parts of the body instead of defending it against the disease. It causes conditions such as rheumatoid arthritis and lupus.
“These results demonstrate the need to test for symptoms of autoimmune disease in patients with symptoms of long-term COVID that last for a year or more,” senior author Manali Mukherjee of McMaster University said in a press release from the European Lung Foundation.
In a press release, McMaster Mukherjee added: “Overall, don’t worry if he feels unwell immediately after infection as the chances of recovery within 12 months are very high and only because you have the typical long COVID symptoms within three months. does not mean that they will stay forever.
“However, the study highlights that after 12 months, if you are still feeling unwell and your symptoms persist or worsen, you should definitely seek medical attention.”
23% exercise intolerance
In the second study, Norwegian researchers assessed the results of the cardiopulmonary exercise test in 210 patients with COVID-19 12 months after their discharge from the hospital, as well as changes in cardiopulmonary function from 3 to 12 months.
The results were compared with the results of the matched uninfected controls. The mean age of the patients was 58.1 years.
After 12 months, 23% of participants showed exercise intolerance related to circulation (28%), ventilation (17%), and other factors such as rehab and dysfunctional breathing (55%). Significant increases in peak oxygen uptake and aerobic capacity occurred from 3 to 12 months, although controls still had higher aerobic capacity than those with long COVID.
“Deconditioning appeared to be the most common exercise restriction, but other unknown mechanisms may have contributed to exercise intolerance,” the authors concluded.