There is a concept called herd immunity. When enough people have taken vaccination against a disease it stops spreading because if cannot infect more people. If

There is a concept called herd immunity. When enough people have taken vaccination against a disease it stops spreading because if cannot infect more people. If people then stop taking vaccines herd immunity does not work. Herd immunity https://en.wikipedia.org/wiki/Herd_immunity https://en.wikipedia.org/wiki/Herd_immunity