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Canadian study builds on link between long COVID and autoimmune diseases

Abnormal antibodies known to cause autoimmune disease, persisted in patients a year after infection

Some long COVID patients suffering symptoms including fatigue and shortness of breath are showing signs of autoimmune diseases like rheumatoid arthritis and lupus, suggests a Canadian study that builds on similar findings elsewhere.

Manali Mukherjee, who led the study and is a respiratory researcher at McMaster University in Hamilton,said two specific abnormal antibodies, or autoantibodies, which attack healthy tissues and are known to cause autoimmune disease, persisted in about 30 per cent of patients a year after they became infected.

The research was based on blood samples from patients who were diagnosed with COVID-19 between August 2020 and September 2021 and received care at two hospitals in Vancouver and another in Hamilton.

The persistence of autoantibodies for a year or longer points to the need for patients to see a specialist who could test for signs of autoimmune disease, she said of conditions that also include Type 1 diabetes and multiple sclerosis.

“If you are having long COVID symptoms, even 12 months after getting COVID, please consider getting a rheumatological checkup, just to make sure that there is no trajectory towards systemic disease,” Mukherjee said.

The study, which also involved Dr. Chris Carlsten, from the University of British Columbia’s division of respiratory medicine, was published Thursday in the European Respiratory Journal and involved 106 patients.

The work supports emerging research on long COVID, which mostly affects women, Mukherjee said.

A study of 300 patients published earlier this year in the journal Cell by researchers in the United States was the first to show that autoantibodies among those infected with the virus can lead to long COVID symptoms, but it was limited to three to four months after recovery, Mukherjee said.

A Swiss study of 90 patients published last April in the journal Allergy suggested autoantibodies can be present a year following infection in 40 per cent of patients.

“But this study confirms the presence of specific autoantibodies and is further associated with persistence of fatigue and breathlessness, two core long COVID symptoms, at 12 months,” she said.

Mukherjee, who contracted long COVID herself in January 2021 after starting her research on the illness, said she experienced fatigue, shortness of breath, headaches and brain fog.

“The headaches used to be so bad, and it relapses. You’ll be fine, and then suddenly, you relapse,” she said, adding she is back to about 75 per cent of her usual energy level but has learned to prioritize her health over working long hours and ensures she gets enough sleep.

Mukherjee is now studying long COVID patients over two years to see how their levels of autoantibodies change in the longer term.

Calgary resident Sarah Olson said long COVID has prevented her from returning to her job as a kindergarten teacher since she contracted the illness in January 2021.

“There’s no such thing as pushing through. You just get sicker and sicker in new ways,” said Olson, who has a nine-year-old son and an 11-year-old daughter and deals with brain fog, fatigue, shortness of breath and other symptoms.

“Until this spring, I couldn’t stand still for long but I could walk at a moderate pace. Now, I can’t do that anymore. I need a walker. I’ll be 41 this Saturday, and I need a walker.”

Olson said she has also been diagnosed with myalgic encephalomyelitis, or chronic fatigue syndrome, though Mukherjee said a definitive link between that debilitating, long-term condition and long COVID has not been established.

Olson said the main concern is that she will never recover from long COVID.

“If I’m not able to manage my symptoms by resting and pacing as much as I need to without ever getting stressed out, then I have every reason to believe that I would continue to get worse,” she said through tears.

“The research needs to hit some breakthrough because they’re still trying to understand what the underlying cause is,” Olson said, adding that could mean treatment options are far off.

“We’re nearly three years in and we’re still in the dark in a lot of ways.”

—Camille Bains, The Canadian Press

Calgary resident Sarah Olson is seen in an undated handout photo. Olson, a kindergarten teacher, hopes the findings of a study linking long COVID to autoimmune disease will lead to treatment for people like her, so they no longer have to struggle with debilitating symptoms. THE CANADIAN PRESS/HO-Sarah Olson