McMaster researchers investigate causes of long COVID

McMaster University scientists are conducting research on the long-term illness suffered by some patients after they’ve recovered from COVID-19, which may be caused by immune dysfunction.

The Government of Canada is investing $500,000 in this study through the COVID-19 Immunity Task Force (CITF).

Manali Mukherjee, PhD, assistant professor of McMaster’s Department of Medicine, who herself is suffering from what has been called “long COVID”, is the lead investigator.

Along with fellow assistant professors of medicine Konstantinos Tselios, PhD, and Sarah Svenningsen, PhD, she will recruit and track 120 patients with long-haul symptoms.

The funding will allow them to understand if COVID-19 triggers immune responses that cause chronic symptoms and potentially increase the risk of future autoimmune diseases such as lupus.

Mukherjee says up to 15 per cent of Canada’s 1.4 million COVID-19 survivors continue to suffer symptoms, such as breathlessness and brain fog, six months after they are deemed recovered from infection under public health guidelines. Tests on a previous cohort of 40 patients revealed autoantibodies that may cause ongoing illness.

“In contrast to the acute-phase of the disease where increasing age is a risk factor for severe COVID-19 symptoms, for the long COVID syndrome, it’s the younger adults – especially women between 25 and 55 – who are more prone to these long-haul symptoms,” said Mukherjee.

“It may be because younger adults have a more robust immune system. They have the internal resources to go full throttle in killing the virus, but this may actually increase the risk that their immune defenses will go rogue, mounting an attack on the body’s own cells and organs and possibly leading to a full-blown autoimmune condition,” she added.

“Put simply, the soldiers defending your body’s immune system wipe out the COVID-19 intruders, but your own civilians become collateral damage in the process. Also, in general, women are linked to higher risk for developing autoimmune diseases.”

Mukherjee added that the mere presence of rogue antibodies does not always lead to full-blown autoimmune diseases or to long COVID symptoms after an infection. There might be many processes involved – and the funding will allow the team to investigate that.

“The New England Journal of Medicine says the long-term impacts of COVID-19 will be the next big national disaster in the United States. We are looking at a similar situation north of the border,” said Mukherjee.

“Indeed, the long-term effects of COVID-19 disease are not yet clear, and this is one of several studies we are funding on the topic to better understand the causes and impacts of what the World Health Organisation defines as post-COVID condition,” said Catherine Hankins, MD, CITF Co-Chair.

“The prevalence of post-COVID condition may end up being the long tail of the pandemic, with psychosocial and economic impacts felt long after transmission declines.”