How much pain is caused by infection fallout?

A study of patients killed by COVID-19 shows that there was probably no direct viral invasion of their inflamed muscle and nerve tissue by SARS-CoV-2. Instead, the inflammation was “likely due to circulating cytokines” — a consequence of systemic inflammation, a friendly-fire complication of other viral infections, and not just the coronavirus.

“Muscle inflammation and necrosis are known features of viral myositis, which has been associated with many viruses.”

The significance of this probably goes beyond Covid.

Although this was a study of the effects of acute infections — pathological bonfires, not smouldering coals — it’s likely or at least plausible that the same thing at least partially explains the symptoms of long Covid. And since this nonsense is not limited to Covid…

Just how much puzzling pain, fatigue, and malaise could this phenomenon explain? How often do we humans suffer from muscle pain due to prolonged systemic inflammation in the aftermath of miscellaneous infections? And probably other diverse causes, most of which we aren’t even aware of? How many people with chronic pain/fatigue are basically just afflicted with the long-term fallout from the immune system’s weird reactions to various and sundry threats, reactions that are clearly optimized for long-term survival and not our comfort? (And let’s not forget that some viruses are known to hack our immune responses for their benefit.)

Lots of unanswerable questions with obvious, plausible answers.