[abnry]

Another similar example is EBV, commonly known as mono, which is often associated with chronic fatigue syndrome and fibromyalgia. Viral infection occurs, followed by a prolonged period (sometime years and years) of flu symptoms.

I would guess there is nothing special about the virus aside from it being "high intensity". My best hypothesis is that the symptoms are the result of a maladaptive "freeze response" which results in the symptoms. Viruses don't actually cause pain, it is your body's response to it.

If you want to avoid this scenario with COVID, probably the best thing you can do is to reduce your stress level as much as possible, as I think that is a key risk factor. Exercise is good, but overdoing it is a form of stress!

[PaulKeeble]

Just to point out ME/Chronic Fatigue Syndrome and Fibromylgia are not flu like sysmptoms, at their worst they are more debitating than MS. They both carry a hallmark problem not seen in anything else called Post Exterion Malaise, where the body will crash if mentally or physically overexerted often leaving the patient unable to lift their own body to eat for months along with a raft of significant systemic problems. They have extremely limited total energy. Flu doesn't work like that at all, CFS and Fibro are really bad and its a disgrace of the medical community that they have failed to research it and gaslight the sufferers for 70 years.

[beebmam]

Viruses can absolutely damage and destroy human cells. That alone can trigger a pain response.

[rurban]

But not influenza viri. They are harmless. What is problematic is the immunosystem overreaction, the T-cells destroying everything around. Called cykotine storm.

Also the bacterial infections caused by such rampage. Like pneumonia.