What might cause long Covid and ME/CFS? Persistent virus, immune dysregulation and microclots
Nobody knows yet why some infections leave people ill for years. Scientists have several hypotheses, and none is settled.
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What might cause long Covid and ME/CFS? Nobody knows for certain. The causes of long Covid are not understood, and no single blood biomarker has been shown to reliably identify it. The cause of ME/CFS is unknown too. What exists is a list of , each with some evidence and none settled. They include lasting damage to organs and blood vessels, problems with blood clotting, neurological dysfunction, persistent virus or reactivation of , and autoimmunity.
Why look at the two together? Between 15% and 50% of people with long Covid also meet the diagnostic criteria for ME/CFS. For ME/CFS, studies find impairment in the nervous and immune systems, as well as in energy production, and how viral infections cause it is unclear: it could be via viral persistence or via a "hit and run" mechanism, in which infections dysregulate the immune system or cause autoimmunity.
Three of the show how the evidence looks. Persistent virus: in a subset of people with long Covid there is evidence that SARS-CoV-2 remains in the body after the acute infection, but persistent virus has also been found in people without long Covid, at a lower rate. Autoimmunity: some studies report , antibodies aimed at the body's own proteins, but not all do. : issues with blood clotting can include hyperactive platelets and microclots, which may induce oxygen shortage in tissues.
Organ damage from the acute infection can explain a part of the symptoms, but long Covid is also observed in people where organ damage seems to be absent. These are to be tested, and more than one could turn out to be true.
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Recap
Long Covid and ME/CFS may share causes, and the leading ideas are hypotheses, not facts.
💡 A trick to remember it · A detective story with several suspects: each has some evidence, none has been convicted.
Surprising fact · Persistent virus has been found in some people with long Covid, but at a lower rate in people without it too.
Sources (3)
No source, no claim. Every fact in this lesson (15 claims) cites at least one of these.