Three out of four people (75%) who became ill due to coronavirus have fully recovered after 12 months, regardless of the severity of their illness. But the remaining 25% – one in four – still have at least one symptom such as cough, fatigue and shortness of breath. These people with persistent symptoms have antibodies in their bodies associated with autoimmune diseases, a new Canadian scientific study shows
The research found that blood samples from long-term Covid-19 patients, who still suffer from fatigue and shortness of breath a year after the initial infection, show clear traces of the autoimmune disease. This discovery may lead to improved diagnosis and treatment of the relatively common long-term Covid-19.
The researchers, led by Assistant Professor Manali Mukherjee of McMaster University in Ontario and Professor Chris Carlsten of the University of British Columbia in Vancouver, who published the relevant publication in the European Respiratory Journal, studied 106 people who had passed Covid-19 in the two years 2020-21 and had been hospitalized for this reason, as well as for comparison hills 22 healthy people and another 34 who had fallen ill with another respiratory infection (not from coronavirus).
Autoimmune diseases occur when the immune system mistakenly attacks healthy parts of the body, causing diseases such as rheumatoid arthritis and systemic lupus erythematosus. In autoimmune disorders the body produces auto-antibodies that do not target harmful viruses and bacteria, but healthy cells and tissues.
The scientists analyzed blood samples and found that almost 80% of patients with long-standing Covid-19 (none had been diagnosed with an autoimmune condition before the pandemic) had two or more such autoantibodies three to six months after the initial infection, with this percentage dropping to 41% (four out of ten people) after one year. On the other hand, almost all healthy volunteers did not have such “boomerang” antibodies in their blood, while also the levels of autoantibodies were relatively low in those who had a non-Covid respiratory infection months ago.
The researchers found that two specific autoantibodies in particular (U1snRNP and SSb-Las), along with other proteins and cytokines that cause inflammation, were present in 30% of patients with prolonged Covid-19 after one year, especially in those who suffered from shortness of breath and persistent fatigue.
“For the majority of patients in our study, even if they had autoantibodies shortly after the initial infection, they were gone by 12 months,” Mukherjee said. But in some patients the autoantibodies persist, and it is precisely these patients who are most likely to continue to suffer symptoms and require medical attention. Our findings highlight the need to screen for signs of autoimmune disease in patients with prolonged Covid-19 lasting a year or more.” As he said, people with symptoms of Covid-19 after one year should see a rheumatologist or other specialist in autoimmune diseases and no longer necessarily a pathologist, pulmonologist or infectious disease specialist.
The researchers will next study patients with very long-lasting Covid-19 of up to two years to see how auto-antibodies change over a longer period of time.