How vaccines work with the immune system. Vaccines provide active immunity to disease. Vaccines do not make you sick, but they can trick your body into believing it has a disease, so it can fight the disease.

What is active and passive immunization?

Active immunization is when we give you a vaccine and your immune system kicks into high gear, and sets up a series of reactions in your body to trick your body into thinking that you've actually had the disease. Passive immunization is when you get those pre-formed antibodies.

What are examples of passive immunity?

Passive immunity can occur naturally, such as when an infant receives a mother's antibodies through the placenta or breast milk, or artificially, such as when a person receives antibodies in the form of an injection (gamma globulin injection).