what is "Herd Immunity"?

[Zenaan Harkness]

Had a friend annoyed at masks the other day, complaining heavily "muh
human right to shop at the supermarket without wearing a mask!"


Interlocutor: So you'd prefer herd immunity?

Complainer: Of course! Weren't you even listening?!

I: Well, do you know what herd immunity means? What is it?

C: Ah, may be not? What is herd immunity?

I: If you survive, you survive; those who die, are left to die, the
rest of the herd is immune…

C: <silence>

I: So you've heard a little about the Spanish flu and the Black Death, right?

C: Yeah..

I: Well, we're the survivors - we are that part of the herd that did not die.