Answer:
building up antibodies in the immune system of those who get a vaccine
Explanation:
A vaccine is a small amount of the live virus being fought, given in such a small amount that is will not get you too sick for your body to fight it off. By inserting that small amount of the virus into the body it can build up its immunity to that virus. This means if the immunized body gets exposed to the virus later it already has its antibodies built up to fight off the virus in full. think of it as a set of instructions on how to get rid of this thing that is attacking you. when mass quantities of the vaccines are spread through a population, the virus has a lesser probability of making lots of people badly sick. But the vaccine will only do its job if a lot of people get it.
