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What Causes Long COVID? Canadian Researchers Think They’ve Found a Key Clue

Teresa Wright wrote . . . . . . . . .

Olympic gold medallist Alex Kopacz may be used to being out of breath when pushing a bobsled, but last year after he was hospitalized for COVID-19, he experienced a very different kind of breathlessness.

He was put on oxygen for two months and experienced a number of other health setbacks in the months following his COVID-19 infection, including blood clots in his lungs and throughout his body.

“It was hard to breathe and pretty much it was just going to be a matter of time to see if my body was going to heal from it,” Kopacz said.

It took him almost four months before he was back on his feet and breathing normally again. But without even an official diagnosis of so-called long COVID, the then-31-year-old didn’t have answers about what was happening to him.

That’s how he became involved in a new Canadian research trial looking at patients suffering from post-COVID syndrome — a study that has identified a potential key culprit causing some people to continue experiencing breathing issues months after contracting COVID-19.

A team of researchers based at five centres across Ontario have zeroed in on a microscopic abnormality in the way oxygen moves from the lungs and into the blood vessels of long COVID patients in their trial.

This abnormality could explain why these patients feel breathless and are unable to perform strenuous activities, says lead researcher Grace Parraga, Tier 1 Canada research chair in lung imaging at Western University’s Schulich School of Medicine & Dentistry.

“Those feelings of breathlessness are completely consistent with our finding that we’re not moving the oxygen as efficiently as we should,” she said.

Many long COVID sufferers have been stumping doctors as to what’s wrong with them, because routine clinical tests and chest exams come back with normal readings.

“It’s very exciting for us to actually find something that’s wrong — that it’s in the patient’s lungs and not in their head,” Parraga said.

The study, which was funded by the Ontario COVID-19 Rapid Research Fund, looked at 34 patients — 12 who had been hospitalized with COVID-19 and 22 others who had not been hospitalized.

The patients were evaluated about nine months after their infection started and were still experiencing a number of debilitating symptoms.

Using an MRI technique developed by Western University that is five times as sensitive and has five times the spatial resolution of a CT scan, the researchers were able to see how tiny branches of air tubes in the lungs were moving oxygen into the red blood cells of their patients.

Red blood cells are responsible for transporting oxygen from the lungs to the rest of the body. Any disruption in the flow of this oxygen to red blood cells will trigger the brain to say, ‘breathe more’ — resulting in a feeling of breathlessness, Parraga explained.

All 34 of the patients who participated in the study were experiencing problems in the level of oxygen being absorbed by their red blood cells.

And they all had the same result, regardless of the severity of their symptoms or whether they had been hospitalized for COVID-19 — another key find, Parraga said.

“All these patients had this abnormality. They all had really serious symptoms, so their exercise scores were low, they were breathless when they exercised and when we measured the oxygen levels in their blood in the tips of their fingers after exercise, that was also low.”

And these external measurements corresponded to the abnormality the researchers found in their MRI measurement of the lungs, she said.

“The takeaway is that now we know what’s wrong.”

The reason why this anomaly is happening is not yet known. But identifying this as a possible trigger for these patients’ symptoms is an important step in trying to learn more, Parraga said.

“I think now that we know what’s going on, we can move on to why. And I think the important part is why some people and why not others? How can we predict who is going there and who isn’t? So, that’s going to take a little bit more time for us to get there.”

Dr. Michael Nicholson, a respirologist with the post-acute COVID-19 program at St. Joseph’s Hospital in London, Ont., who co-authored the study, says the findings give patients an identifiable reason why they are still experiencing symptoms months after getting COVID-19.

Up until now, normal tests performed on these patients have not picked up what’s happening to them, so they’re often left to feel as if they’re imagining their illness, he said.

“There’s nothing that’s absolutely obvious. And so these individuals are now given an answer that actually there is something at this very particular site down the pathway that is abnormal,” Nicholson said.

“For these other individuals, that now we can say, ‘I understand your symptoms, I think we have a better appreciation of what’s happening. We don’t necessarily know it completely.’… That’s a positive for them.”

The research team acknowledges the sample size of this study, which has been peer-reviewed, is small and therefore that results should be considered “exploratory and hypothesis-generating.”

But that hasn’t tempered their excitement at the prospect of making headway in understanding long COVID and taking one step closer to understanding how to treat it.

“I think it’s a nice, scientific Pandora’s box, so to speak, of opening up and saying, ‘OK, now we have to focus on why this is happening,’” Nicholson said.


Source : Global News


Read also at Western News

Innovative lung-imaging technique shows cause of long-COVID symptoms . . . . .

Omicron Amps Up Concerns About Long COVID and Its Causes

Laura Ungar and Lindsey Tanner wrote . . . . . . . . .

More than a year after a bout with COVID-19, Rebekah Hogan still suffers from severe brain fog, pain and fatigue that leave her unable to do her nursing job or handle household activities.

Long COVID has her questioning her worth as a wife and mother.

“Is this permanent? Is this the new norm?” said the 41-year-old Latham, New York, woman, whose three children and husband also have signs of the condition. “I want my life back.’’

More than a third of COVID-19 survivors by some estimates will develop such lingering problems. Now, with omicron sweeping across the globe, scientists are racing to pinpoint the cause of the bedeviling condition and find treatments before a potential explosion in long COVID cases.

Could it be an autoimmune disorder? That could help explain why long COVID-19 disproportionately affects women, who are more likely than men to develop autoimmune diseases. Could microclots be the cause of symptoms ranging from memory lapses to discolored toes? That could make sense, since abnormal blood clotting can occur in COVID-19.

As these theories and others are tested, there is fresh evidence that vaccination may reduce the chances of developing long COVID.

It’s too soon to know whether people infected with the highly contagious omicron variant will develop the mysterious constellation of symptoms, usually diagnosed many weeks after the initial illness. But some experts think a wave of long COVID is likely and say doctors need to be prepared for it.

With $1 billion from Congress, the National Institutes of Health is funding a vast array of research on the condition. And clinics devoted to studying and treating it are popping up around the world, affiliated with places such as Stanford University in California and University College London.

WHY DOES IT HAPPEN?

Momentum is building around a few key theories.

One is that the infection or remnants of the virus persist past the initial illness, triggering inflammation that leads to long COVID.

Another is that latent viruses in the body, such as the Epstein-Barr virus that causes mononucleosis, are reactivated. A recent study in the journal Cell pointed to Epstein-Barr in the blood as one of four possible risk factors, which also include pre-existing Type 2 diabetes and the levels of coronavirus RNA and certain antibodies in the blood. Those findings must be confirmed with more research.

A third theory is that autoimmune responses develop after acute COVID-19.

In a normal immune response, viral infections activate antibodies that fight invading virus proteins. But sometimes in the aftermath, antibodies remain revved up and mistakenly attack normal cells. That phenomenon is thought to play a role in autoimmune diseases such as lupus and multiple sclerosis.

Justyna Fert-Bober and Dr. Susan Cheng were among researchers at Cedars-Sinai Medical Center in Los Angeles who found that some people who have had COVID-19, including cases without symptoms, have a variety of these elevated “autoantibodies” up to six months after recovering. Some are the same ones found in people with autoimmune diseases.

Another possibility is that tiny clots play a role in long COVID. Many COVID-19 patients develop elevated levels of inflammatory molecules that promote abnormal clotting. That can lead to blood clots throughout the body that can cause strokes, heart attacks and dangerous blockages in the legs and arms.

In her lab at Stellenbosch University in South Africa, scientist Resia Pretorius has found microclots in blood samples from patients with COVID-19 and in those who later developed long COVID. She also found elevated levels of proteins in blood plasma that prevented the normal breakdown of these clots.

She believes that these clotting abnormalities persist in many patients after an initial coronavirus infection and that they reduce oxygen distribution to cells and tissue throughout the body, leading to most if not all symptoms that have been linked to long COVID.

IT CAN HIT NEARLY ANYONE

While there’s no firm list of symptoms that define the condition, the most common include fatigue, problems with memory and thinking, loss of taste and smell, shortness of breath, insomnia, anxiety and depression.

Some of these symptoms may first appear during an initial infection but linger or recur a month or more later. Or new ones may develop, lasting for weeks, months or over a year.

Because so many of the symptoms occur with other illnesses, some scientists question whether the coronavirus is always the trigger. Researchers hope their work will provide definitive answers.

Long COVID affects adults of all ages as well as children. Research shows it is more prevalent among those who were hospitalized, but also strikes a significant portion who weren’t.

Retired flight attendant Jacki Graham’s bout with COVID-19 at the beginning of the pandemic wasn’t bad enough to put her in the hospital. But months later, she experienced breathlessness and a racing heart. She couldn’t taste or smell. Her blood pressure shot up.

In the fall of 2020, she became so fatigued that her morning yoga would send her back to bed.

“I’m an early riser, so I’d get up and push myself, but then I was done for the day,” said Graham, 64, of Studio City, California. “Six months ago, I would have told you COVID has ruined my life.”

Hogan, the New York nurse, also wasn’t hospitalized with COVID-19 but has been debilitated since her diagnosis. Her husband, a disabled veteran, and children ages 9, 13 and 15 fell ill soon after and were sick with fever, stomach pains and weakness for about a month. Then all seemed to get a little better until new symptoms appeared.

Hogan’s doctors think autoimmune abnormalities and a pre-existing connective tissue disorder that causes joint pain may have made her prone to developing the condition.

POTENTIAL ANSWERS

There are no treatments specifically approved for long COVID, though some patients get relief from painkillers, drugs used for other conditions, and physical therapy. But more help may be on the horizon.

Immunobiologist Akiko Iwasaki is studying the tantalizing possibility that COVID-19 vaccination might reduce long COVID symptoms. Her team at Yale University is collaborating with a patient group called Survivor Corps on a study that involves vaccinating previously unvaccinated long COVID patients as a possible treatment.

Iwasaki, who is also an investigator with the Howard Hughes Medical Institute, which supports The Associated Press’ Health and Science Department, said she is doing this study because patient groups have reported improvement in some people’s long COVID symptoms after they got their shots.

Study participant Nancy Rose, 67, of Port Jefferson, New York, said many of her symptoms waned after she got vaccinated, though she still has bouts of fatigue and memory loss.

Two recently released studies, one from the U.S. and one from Israel, offer preliminary evidence that being vaccinated before getting COVID-19 could help prevent the lingering illness or at least reduce its severity. Both were done before omicron emerged.

Neither has been published in a peer-reviewed journal, but outside experts say the results are encouraging.

In the Israeli study, about two-thirds of participants received one or two Pfizer shots; the others were unvaccinated. Those who had received two shots were at least half as likely to report fatigue, headache, muscle weakness or pain and other common long COVID symptoms as the unvaccinated group.

UNCERTAIN FUTURE

With few clear answers yet, the future is murky for patients.

Many, like Graham, see improvement over time. She sought help through a long COVID program at Cedars-Sinai, enrolled in a study there in April 2021, and was vaccinated and boosted.

Today, she said, her blood pressure is normal, and her sense of smell and energy level are getting closer to pre-COVID levels. Still, she wound up retiring early because of her ordeal.

Hogan still struggles with symptoms that include agonizing nerve pain and “spaghetti legs,” or limbs that suddenly become limp and unable to bear weight, a condition that also affects her 13-year-old son.

Some scientists worry that long COVID in certain patients might become a form of chronic fatigue syndrome, a poorly understood, long-lasting condition that has no cure or approved treatment.

One thing’s for sure, some experts say: Long COVID will have a huge effect on individuals, health care systems and economies around the world, costing many billions of dollars.

Even with insurance, patients can be out thousands of dollars at a time when they’re too sick to work. Graham, for example, said she paid about $6,000 out of pocket for things like scans, labs, doctor visits and chiropractic care.

Pretorius, the scientist in South Africa, said there is real worry things could get worse.

“So many people are losing their livelihoods, their homes. They can’t work anymore,” she said. “Long COVID will probably have a more severe impact on our economy than acute COVID.”

Source: AP


Read also:

Can you get long COVID after an infection with omicron? . . . . .

Over One Million People Reporting Long COVID in the UK

Source : Statista