Prions are mis-folded proteins which cause a cascade of mis-folding in proteins of the same structure which are already present in the body. The mis-folding affects their biological activity.
The “proteins of the same structure” we are talking about here are virus spike proteins. Assuming that there is a pathway that leads to the misfolded form propagating to begin with, the damage is that other spike proteins don’t work. These proteins, however, were never intended to perform any function whatsoever.
