There was an article dated 6/16/22 posted on Scien
Post# of 148279
https://www.science.org/content/article/what-...g-theories
CLUES TO LONG COVID
Scientists strive to unravel what is driving disabling symptoms
They span three continents, but a trio of researchers who’ve never met share a singular focus made vital by the still-raging pandemic: deciphering the causes of Long Covid and figuring out how to treat it.
Almost 2 years ago in Italy, pediatric infectious disease doctor Danilo Buonsenso, who works at Gemelli University Hospital, started to see children who, months after mild infections with SARS-CoV-2, were still short of breath and had crushing fatigue and other symptoms. He now suspects that, in some of them, the cells and tissues that control blood flow are damaged and the blood’s tendency to clot is amplified. Minute blood clots, leftover from the viral assault or fueled by its aftermath, might be gumming up the body’s circulation, to disastrous effect from the brain to joints. “In some patients we have specific areas where no blood flow comes in” or the flow is reduced, Buonsenso says. Is that driving their lingering symptoms? “I can’t say this is the truth, of course. But this makes sense.”
Meanwhile, in the United States, microbiologist Amy Proal can’t stop thinking about a second leading Long Covid theory: that the coronavirus keeps hurting people by stubbornly enduring in the body, even after acute infection passes. Studies have shown “the virus is capable of persistence in a wide range of body sites,” especially nerves and other tissues, says Proal, who works at the PolyBio Research Foundation, a nonprofit in Washington state. She recently caught COVID-19 for the third time.
Down under in Australia, immunologist Chansavath Phetsouphanh of the University of New South Wales, Sydney, is chasing a third lead, motivated by what the blood of Long Covid patients has divulged: an immune system gone haywire even 8 months after they’d first tested positive. He had assumed that immune cells galvanized to fight off infection would have calmed down over that time span. So, “It was a surprise that these cells did not recover,” says Phetsouphanh, who is working to set up an international Long Covid collaboration.
For each of these researchers—and many others exploring the causes of Long Covid—untangling the complex syndrome, with a still-evolving definition, is a laborious, step-wise process. First, they must show that a possible contributor—such as minuscule clots, lingering virus, or immune abnormalities—crops up disproportionately in people with Long Covid. Then comes the hard part: proving that each of these traits, alone or in combination, explains why the coronavirus has rendered millions of people shadows of their former selves.
All agree that solo operators are unlikely. Lingering virus, for example, could attack the circulatory system, triggering blood clots or chronic inflammation. “I see this as a triangle,” Buonsenso says, with each trigger potentially explaining, or even amplifying, the others.
A final challenge is identifying treatments that ease or reverse these abnormalities and help patients feel better. In the United Kingdom, home to a widely praised effort to identify immediate COVID-19 treatments, researchers are launching a clinical trial that will be among the largest worldwide to test potential Long Covid therapies in a randomized, statistically robust manner. But more such studies are needed—and time is of the essence. In May, the U.S. Centers for Disease Control and Prevention reported that a review of the medical records of nearly 2 million people suggested at least one in five of those diagnosed with COVID-19 had developed conditions characteristic of Long Covid. Other studies have found roughly similar rates. Some recent research suggests the risk for vaccinated people is somewhat lower, but vaccination’s power to head off the syndrome remains uncertain.