Canadian research could lead to simple test, possible treatment, for long COVID

The researchers are now working on a first-of-its kind blood test that could diagnose long COVID.

Dr. Douglas Fraser lead researcher in London, Ont., team that has identified unique biomarkers connected with long COVID. Photo by Handout

Researchers in London, Ont., have identified unique biomarkers that they hope will lead to a simple diagnostic blood test for long COVID and, possibly, eventual treatments.

Scientists at Lawson Health Research Institute found that patients with long COVID had 14 elevated biomarkers associated with their blood vessels. Two of those biomarkers could be used to identify long COVID in patients with 96 per cent accuracy, based on the study.

The finding could be game-changing at a time when there are increasingly dire warnings about the impact of long COVID on individuals and on society.

Some people who have been infected with the virus experience long-term effects, ranging from brain fog and fatigue, to respiratory and heart symptoms, to neurological symptoms. Women are more likely than men to have the condition, as are those who were hospitalized with severe COVID-19.

It is estimated 30 to 40 per cent or more of people who get acute COVID infections will have some form of prolonged symptoms lasting weeks and months. For some people, long COVID symptoms are so severe that they can no longer work or resume regular functions of daily life.

Tedros Adhanom Ghebreyesus, director general of the World Health Organization, recently called for immediate action to tackle long COVID, saying tens of millions of people, and perhaps more, had been affected: 15 per cent of those for more than a year.

Dr. Douglas Fraser, Lawson Health scientist and critical care physician at London Health Sciences Centre, who is lead researcher of the paper published this past week in Molecular Medicine, cited statistics from the United States showing that an estimated 110,000 people were being diagnosed with long COVID every day and 15 per cent of the workforce was currently off with long COVID.

Fraser said his team’s research was an important step toward better understanding, quickly diagnosing and possibly treating long COVID.

“Physicians currently rely on symptoms alone to diagnose the condition, but our research offers a unique profile of blood biomarkers that could be used in a clinical test,” he said.

A simple way to diagnose long COVID is crucial to patients, who are sometimes treated as if their symptoms are psychosomatic, he said. For doctors, he said, it can also be difficult to know how to understand a patient’s symptoms because symptoms can be so diffuse, often leading to multiple tests.

Fraser and his team’s work focused on the blood vessels, which he calls the common denominator among organ systems affected in long COVID. Fraser’s team were among the first researchers to demonstrate that the coronavirus causing COVID-19 could directly infect the cells lining the blood vessels, adding to the understanding that COVID-19 is a disease of the blood vessels.

The London researchers studied 140 blood samples from participants, including those with presumed long COVID, hospital patients with acute COVID-19 and healthy control subjects. They identified 14 elevated biomarkers associated with blood vessels. With the help of machine learning, they discovered that two of those biomarkers — ANG-1 and P-SEL — could be used to classify long COVID with 96 per cent accuracy.

The researchers are now working on a first-of-its kind blood test that could diagnose long COVID.

Fraser said the test, using a drop of blood, could come up with a diagnosis in 10 to 20 minutes. He said the diagnosis could tell patients whether they have had COVID-19 as well as whether they have long COVID.

By identifying the biomarkers involving blood vessels, Fraser said his team had also provided insight into possible treatments. They are now trying to develop therapeutics to treat long COVID, looking at repurposing already-existing drugs that affect blood vessel growth.

Fraser said patients should know that damage to their blood vessels would improve with time. He also said knowing there was a potential diagnostic tool should give them hope.

Dr. Michael Nicholson, associate scientist at Lawton, a respirologist at St. Joseph’s and associate professor at Schulich Medicine and Dentistry, said the research advanced the understanding of long COVID with the potential to improve diagnosis and patient care.

“Long COVID is a relatively new condition and we have much to learn about it.”

The research was supported by funding from the London Health Sciences Foundation, the London Community Foundation and provincial innovation funding.