immunization
Americannoun
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the fact or process of becoming immune, as against a disease.
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Finance. a method of protection against fluctuating bond interest rates by investing in securities having different yields and terms.
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The process of inducing immunity to an infectious organism or agent in an individual or animal through vaccination.
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A vaccination that induces immunity. A recommended schedule of immunizations for infants and young children includes vaccines against diphtheria, polio, tetanus, measles, mumps, and rubella.
Usage
What’s the difference between immunization, vaccination, and inoculation? In the context of medicine, the words immunization, vaccination, and inoculation are often used in overlapping ways, and for good reason—they all involve the process of introducing a substance (especially a vaccine) into a person’s body with the goal of preventing them from getting a particular disease. Vaccination is the most specific of the three terms, because it always involves introducing a vaccine, which usually consists of a small amount of a killed, weakened, or otherwise modified version of a disease (such as a virus or bacterium). While inoculation has other meanings outside the context of medicine, in modern healthcare it’s typically used interchangeably with vaccination (though it’s used less commonly). Immunization is slightly different—it refers to the process of providing immunity from a specific disease. While the goal of vaccinating someone is often to immunize them, not all vaccines provide permanent immunity. Some vaccines provide what amounts to long-term immunity, while others only lead to a temporary protection, after which the body “forgets” how to make certain antibodies. In these cases, a booster shot or dose is often required, consisting of a follow-up vaccination to boost or renew the protection gained from the earlier vaccination. Both vaccination and inoculation can refer to a shot or dose, as opposed to the process of providing or receiving such doses, as in I’m scheduled to get a vaccination on Friday. The word immunization can be used in the same way to refer to such a vaccination when it’s one that provides immunity, as in Have you received all of your immunizations?Want to learn more? Read the full breakdown of the difference between immunize, vaccinate, and inoculate.
Discover More
Frequently, schoolchildren are required by state law to be immunized against certain diseases. Because of such widespread immunization, many diseases that used to be fairly common, including smallpox, tetanus, and whooping cough, have become rare.
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Origin of immunization
Compare meaning
How does immunization compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
Immunization is the process of getting a shot that boosts your body's defenses against a certain disease. Before international travel, you may need to get additional immunizations. Strictly speaking, immunization is action of stimulating your immune system to fight off infection, with the help of a vaccine. You can also use immunization interchangeably with vaccination or inoculation, so you might say, "While I was at the doctor, I went ahead and got my flu immunization." The word comes from immune, "exempt from disease," and its Latin root, which means "exempt."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The combination of reduced immunization and poor nutrition build on each other.
From Los Angeles Times ● Jul. 3, 2026
Neither Inovio or Novavax appear to be as central to hantavirus immunization efforts as Moderna, however.
From Barron's ● May 11, 2026
They called the medical groups’ request to block the vaccine panel from meeting publicly, and the HHS from disseminating information about immunization recommendations, “an extraordinarily unusual advice-banning” proposal.
From The Wall Street Journal ● Mar. 16, 2026
They are likely to recommend further changes to the childhood immunization schedule.
From Salon ● Mar. 11, 2026
She opens up the folder and examines the immunization record, the birth certificate.
From "The Namesake" by Jhumpa Lahiri
I focus our conversation on their specific concerns, and I’m open about specific side effects that different immunizations can have.
From Los Angeles Times ● Jul. 28, 2026
Other diseases on the AAP’s recommended schedule for immunizations include chickenpox, measles and polio.
From The Wall Street Journal ● Jan. 26, 2026
Now 11 vaccines are recommended for all children, while immunizations against influenza, hepatitis A and B, rotavirus, meningococcal disease, COVID-19 and RSV pushed into “high-risk” or “shared clinical decision-making” categories.
From MarketWatch ● Jan. 6, 2026
"At a time when parents, pediatricians and the public are looking for clear guidance and accurate information, this ill-considered decision will sow further chaos and confusion and erode confidence in immunizations," Dr. Racine added.
From BBC ● Jan. 5, 2026
When she takes him in his pram for his immunizations at the pediatrician’s, she stands outside the room and plugs up her ears.
From "The Namesake" by Jhumpa Lahiri
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
