When the human body gets a disease, it learns how to fight that disease. It creates “antibodies” that are specially made just to fight that disease. If the disease ever tries to come back, the antibodies are there, ready to fight it. The body is now “immune” to the disease.
The only problem is, you have to suffer through the disease to become immune to it. That’s no fun.
Scientists figured out that if they gave the human body just a weak, tiny bit of the thing that causes the disease, they could “teach” the body how to fight the disease without ever having to suffer through it.
That’s what a vaccine is – a special medicine that trains the human body in how to fight a disease. It’s a way to become immune without ever having to get sick. And it also means that a person is less likely to give the disease to someone else.
Some vaccines are given as a shot, some can be swallowed, and some can even be breathed in through the nose.
When someone is given a vaccine, it is called “getting a vaccination” or “getting vaccinated”.