Vaccines help in developing immunity. A vaccine for a particular disease is made of killed or weakened germs (or its parts) of the same disease; for instance, the polio vaccine is made from polio virus. Vaccine is administered with the help of an injection. The vaccine triggers the body's immune system to produce antibodies against the killed or weakened germs introduced inside the body. This way, a memory immune response is created, just like a training exercise. This developed memory immunity can help the body fight against the actual germs when they infect an individual. Thus, vaccines for different diseases can protect us against those diseases.