I know too. May I...?

The vagus nerve is part of the autonomic nervous system. That system, as opposed to the central nervous system, is largely concerned with stuff that we don't have to think much about, such as heart rate and not forgetting to breathe. It connects many major organs with parasympathetic motor fibres. Because its branches reach many body parts and because many body parts are implicated in long covid, the nerve has been studied in samples of patients with long covid, and it's been found that observable vagus nerve abnormalities occur in some of those patients. At present, the evidence is observational only but it does look significant.

Fact-checking and corrections welcome. I'm a botanist really. Snarky remarks and accusations of thread-bossing are not welcome.