Long Covid

So far there are more theories than clear answers for what's going on, and there is good reason to think the varied constellation of symptoms could have different causes in different people. Maybe the virus is still hiding in the body somewhere, in some, directly damaging nerves or other parts of the body. Maybe the chronic presence of the virus, or remnants of the virus, keeps the immune system kind of simmering at a low boil, causing the symptoms. Maybe the virus is gone, but left the immune system out of whack, so it's now attacking the body. Or maybe there's another cause.

"It's still early days. But we believe that long COVID is not caused by one thing. That there are multiple diseases that are happening," says Akiko Iwasaki, a professor of immunobiology at Yale University who is also studying long COVID.

[...]

"We are finding elevated cytokines in long-COVID patients and we're trying to decode what those cytokines mean. We're also seeing some distinct auto-antibody reactivity and are trying to find out what those antibodies are doing and whether they are causing harm," Iwasaki says.

[...]

Yet another clue found in one subgroup of patients is an unusual pattern of activity by key immune system cells, such as as T-cells, which may support the idea that the virus is hiding in the body.

"That's a signature or pattern which could be consistent with a low-level, but persistent, infection in the long-COVID syndrome patient," says Dr. Igor Koralnik at Northwestern Feinberg School of Medicine.

[...]

Yet another clue found in one subgroup of patients is an unusual pattern of activity by key immune system cells, such as as T-cells, which may support the idea that the virus is hiding in the body.

"That's a signature or pattern which could be consistent with a low-level, but persistent, infection in the long-COVID syndrome patient," says Dr. Igor Koralnik at Northwestern Feinberg School of Medicine.

  NPR

...but hey, do what you want...you will anyway.