Potentially it might be helpful to reduce inflammation and neuroinflammation in ME/CFS, especially if you subscribe to the vagus nerve infection hypothesis of ME/CFS.
But note that they are working with the surgically implanted electrode form of vagus nerve stimulation, rather than the external TENS machine-type vagus nerve stimulation devices.
I am not sure if their setup could be adapted for use with external vagus nerve stimulation.
The concept seems interesting: with their setup, using a kilohertz frequency sine wave electrical stimulation of the vagus, they block the incoming (afferent) vagus nerve signals from the body to the brain (signals which trigger inflammatory processes), but they don't block the outgoing (efferent) vagus nerve signals from the brain to the body (which are important for various bodily functions).
If I understand correctly, this kilohertz frequency blocks the incoming (afferent) signals, but not the outgoing (efferent) signals in the vagus nerve. So it is a selective block.
In
the study, they say that the inflammatory processes triggered by the incoming vagus nerve signals lead to activation of the hypothalamic-pituitary-adrenal (HPA) axis, activation of the sympathetic nervous, and an increase in pro-inflammatory cytokines. So you can block all these effects by blocking the incoming vagus nerve signals with their system.