I think this idea that a direct vagus nerve infection produces an amplified sickness response is a fascinating hypothesis.
I'm not sure how you could prove it without finding the site of infection, which I imagine could be anywhere in the vagus nerve and quite small, but it's still very intriguing.
It's also interesting that, in some cases, ME/CFS seems to begin with something like a vaso-vagal attack. Dr. Ramsay's definition of ME mentions onset (in some cases) with a sudden attack of "vertigo," which is the main feature of a vaso-vagal episode.
Quite a few patients (myself included) also report a low resting pulse rate. I was also told that I have marked respiratory sinus arrhythmia - a benign condition in which the heart speeds up when inhaling and slows down when exhaling. My blood pressure is also noticeably higher when inhaling than when exhaling. These all appear to be features of high vagal tone.
As I recall, in otherwise healthy people high vagal tone is associated with lower mortality from cardiovascular events. Indeed, early in my illness, my doctor assumed I was an athlete due to my low resting pulse rate. Following a treadmill test, his view altered by 180 degrees and he assumed I was deconditioned. Frankly, I wouldn't say I was a athlete, but, as an active young man, neither was I deconditioned. It was an oddity of the illness that made it appear that I was both.
I'm not quite sure from the interview whether an alteration of vagal tone is a feature of the hypothesis, but the idea that there is some kind of effect on the vagus nerve - be it direct infection or a response to circulating cytokines from some other immune response - could (perhaps) be mucking with vagal tone while at the same time be signaling an exaggerated sickness response to the brain is interesting stuff.
[I do wonder if some kind of low level chronic infection in the lining of the intestine could produce this effect if it were in close contact with the vagus nerve in that location. The gut is certainly high on the suspect list in this disease.]
How this might relate to B-cells, autoimmunity and the rituximab effect is over my head, but I'm definitely intrigued by this idea.