I get the sense that covid is “where the light is” in terms of the search for after-effects of sickness - I had a non-covid cold (at least several at home 15 minute tests were negative) in 2022 that had long symptoms, my sinuses and ear canals still feel different than before.
It may be that covid does unique physiological damage, but it could also be that most severe sicknesses do some sort of permanent damage.
I wonder how much of this is unique to covid, is my point.
Blood vessel/nerve damage is likely specific to COVID, the more general energy utilisation disorders seemingly aren't, and are triggered by any kind of ongoing inflammation, and often seem to last after any sufficiently severe immune events, though it's possible that this is related to e.g. herpesviral reactivation.
Energy utilization disorders inevitably cause nerve damage if left untreated. It can be a slow process, it can be fast, but the end result is nerve and tissue damage leading to a plethora of symptoms and secondary diseases.
Nerve damage does not necessarily mean irreversible consequences, depending on the degree. E.g. any amount of sleep deprivation, both in terms of quantity and quality, causes (minuscule) brain damage, but even people with severe sleep apnea mostly recover with treatment.
Likewise, PDE5 inhibitors and presumably other med classes seem capable of nearly reversing mild-to-moderate nerve damage through local NGF release secondary to improved endothelial function and nerve blood supply.
It may be that covid does unique physiological damage, but it could also be that most severe sicknesses do some sort of permanent damage.
I wonder how much of this is unique to covid, is my point.