[xorcist]

There absolutely is. You just think the word immunity means something else.

After vaccination or a passed infection the immune response is there. When a sufficient immune resopnse from a large enough portion if the population is enough to lower the critical cases below some threshold, we call that type of immunity herd immunity.

It's not binary, but a useful concept nonetheless, and one that some people devote their professional lives to. It can be observed every flu season.