What is the difference between vaccination and immunization?

Dr. Darria Gillespie, MD
Emergency Medicine Specialist

In most ways that we discuss them, they’re the same thing, but there’s a slight nuance. Immunization refers to building immunity to a certain infectious disease—such as chicken pox, the flu or polio. That can be built two ways. The first is by getting sick from the disease. For instance, if you catch the chicken pox, it will make you sick, but after you recover, you’ll be immune to it. The second way is by receiving a vaccine. With a vaccine, you’re still exposed to the illness, but in either an extremely small amount or in a form that has been inactivated or killed, so it can’t actually make you sick.

In both ways, your body is exposed to the illness, or what we call the antigen, and it makes immune cells against that disease, so your body can fight it off if you’re ever exposed to it again.

Vaccines are the products that produce immunity from a disease and can be administered orally, via injection or through an aerosol spray. There are two types of vaccines, inactivated and live, and these present different indications after administration. Vaccinations are the act of administering the vaccine that produces immunity in the body against the organism. Immunization is the process by which one becomes protected from a disease. Vaccines cause immunization, and sometimes diseases can also trigger immunization after the individual recovers from the disease.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.