What is immunity?

Immunity is the capacity of the human body to defend itself against substances or infections…

… such as parasites, bacteria or viruses that can make us ill.

When we say someone is “immunized” against a disease, that means they can’t catch it any more.

But how do you become “immunized”?

From birth, our body defends itself against intruders: it stops them from getting in, destroys them or gets rid of them.