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Understanding Long Covid

When COVID-19 first emerged as a global health threat, great attention was given to the acute phase of the disease. The immediate, short-term effects were devastating for many, and led to wave after wave of increased hospital pressures.

But with each successive wave, more and more of those who became ill started to realize that their symptoms were lasting much longer compared to others who had fully recovered. Brain fog, dizziness, headaches, fatigue, and loss of smell – for some patients, these symptoms lingered well after they were no longer infectious.

As patients shared their experiences with physicians and support groups, the term “Long Covid” became the unofficial name of this emerging syndrome. Researchers now speculate that Long Covid could lead to further complications that include respiratory, neurocognitive, and cardiovascular disorders, among others. Various studies estimate the prevalence of Long Covid to be anywhere from 10 to 50 percent of those infected with COVID-19.

While research on the treatment of acute COVID-19 is still ongoing, others are turning their attention to Long Covid and the complications it brings.

Dr. Manali Mukherjee is an affiliate scientist at The Research Institute of St. Joe’s Hamilton

Dr. Manali Mukherjee was among those who fell ill with COVID-19 in early 2021. Like so many others, Dr. Mukherjee’s symptoms persisted well beyond the acute phase of the disease. For a while, her sense of smell was gone, but then she often started to smell smoke. She also experienced changes in blood pressure, fatigue, and brain fog – an inability to concentrate or think clearly for long periods.

“There were good weeks, and then bad weeks,” says Dr. Mukherjee. “I just kept thinking, ‘I’m a trained immunologist, I know what might be happening to me, and I’m getting this anxious. What’s happening to other people who don’t know about it?’”

Schooled in cell biology, immunology, and pharmacology, Dr. Mukherjee came to St. Joe’s Firestone Institute for Respiratory Health as a post-doctoral fellow working with Dr. Parameswaran Nair in 2014. Dr. Nair is a world-renowned clinician-scientist whose lab studies airway immunity and eosinophilic asthma using novel imaging methods, sputum cytology, and other innovative techniques.

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Brain fog is not a medical term, but it has been used frequently to describe the inability to concentrate or think clearly. Those experiencing Long Covid have noted their thinking is sluggish and their memory is not as sharp as before.

Now, Dr. Mukherjee leads a team of researchers as a St. Joe’s affiliate scientist and assistant professor of medicine at McMaster.

In the midst of her Long Covid symptoms, Dr. Mukherjee’s years of training sparked an idea – what if COVID-19 caused an overactive autoimmune response? After all, other viruses can act as triggers for autoimmune diseases.

This hypothesis led to some initial research and ultimately a grant application to the Canadian Institutes of Health Research (CIHR) to study autoimmune post-acute COVID-19 syndrome, or AI-PACS.

At Dr. Mukherjee’s lab within the Firestone Institute for Respiratory Health, researchers are uncovering the auto-immune mysteries of COVID-19

In July 2021, The Research Institute was excited to announce that Dr. Mukherjee and her team had been awarded a $500,000 CIHR grant to study AI-PACS. The grant was awarded under CIHR’s Emerging COVID-19 Research Gaps and Priorities grant, part of the COVID-19 Immunity Task Force. Participating St. Joe’s researchers include Dr. Sarah Svenningsen, Dr. Dawn Bowdish, Dr. Parameswaran Nair, Dr. Zain Chagla, Dr. Terence Ho, and many others from the Firestone Institute and other disciplines.

As part of the ongoing study, Dr. Mukherjee and her team are looking at blood, lung-function tests, and patient-reported outcomes. Participants will be assessed at three, six, nine, and twelve months after their initial COVID-19 illness.

Ultimately, the goal of this ongoing research is to better understand the virus and how it affects the body and the immune system, and to identify various treatment pathways.

“We need to do studies in bigger numbers, in collaborations, over time,” says Dr. Mukherjee. “And the people who are fighting this, who are going through this, need to come and get themselves enrolled in studies, and stick to the study, so that we can understand this disease.”

Dr. Mukherjee and her team are currently preparing a manuscript that details the association of key inflammatory cytokines (proteins used in cellular signalling) with specific Long Covid symptoms. It is expected to be published in the fall of 2022.

Update: Long Covid Patients Show Signs of Autoimmune Disease a Year After Infection posted Sept. 22, 2022

For the latest updates on Long Covid research from St. Joe’s, follow The Research Institute on Twitter and Instagram.