"immunity" in the medical sense always meant "some resistance to" (as opposed to none at all) and never "total protection". Some other colloquial uses of the wo

"immunity" in the medical sense always meant "some resistance to" (as opposed to none at all) and never "total protection". Some other colloquial uses of the word (e.g. in legal) have always made this a bit difficult to understand outside the medical community. Cf. the "immune system" being a very active thing and not binary in practice.