What is the difference between vaccination and immunization?

Dr. Darria Long Gillespie, MD
Emergency Medicine
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.
Marijan Gospodnetic, MD
OBGYN (Obstetrics & Gynecology)
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.

This content originally appeared on the HCA Virginia Physicians blog. 
Anthony L. Komaroff, MD
Internal Medicine
Strictly speaking, vaccination is the giving of vaccines to prevent disease. Immunization means acquiring immunity against disease, that is, protection against getting sick. Successful vaccination results in immunization. Sometimes these distinctions are fuzzy; you may see vaccination and immunization used synonymously. The term inoculation is also commonly used to mean vaccination.

Continue Learning about Vaccines & Immunizations

Vaccines & Immunizations

Vaccines & Immunizations

Vaccines are commonly given to children in the form of a shot to help prevent serious diseases like measles and mumps. Vaccines are developed using either dead strains of a disease, weakened strains, or strains of a different dise...

ase. As adults, we receive flu vaccines or may need a booster of childhood vaccines to retain immunity. Travelers may receive vaccines either as a condition of entry to a country, or on recommendation of health officials. Generally there is little or no reaction to a vaccine, but in some cases the vaccine may cause an allergic reaction or a temporary, mild illness. Some vaccines are not safe for pregnant women, so it’s important to check with a healthcare professional.

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.