immunize

American  

[im-yuh-nahyz, ih-myoo-nahyz] / ˈɪm jəˌnaɪz, ɪˈmju naɪz /

especially British, immunise

verb (used with object)

• immunizes,
  present (3rd person singular)
• immunized,
  past participle,  past
• immunizing
  present participle

1. to make immune, or protected from a disease or the like.

   They are organizing a massive health campaign to immunize millions of children.

   George Washington's army immunized its soldiers against smallpox.

2. to shield, exempt, or protect.

   There is no moral or legal basis for immunizing victorious nations from scrutiny over their actions in a war.

3. Law. to grant (a witness) exemption from criminal prosecution, legal liability, or punishment on certain conditions.

   In exchange for her testimony, the court agreed to immunize the witness against prosecution for criminal activities committed during the relevant period.

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immunize British  

/ ˈɪmjʊˌnaɪz /

verb

1. to make immune, esp by inoculation

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Usage

What’s the difference between immunize, vaccinate, and inoculate? In the context of medicine, immunize, inoculate, and vaccinate are often used in overlapping ways, and for good reason—they all involve introducing a substance (especially a vaccine) into a person’s body with the goal of preventing them from getting a particular disease. Vaccinate 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 inoculate has other meanings outside the context of medicine, in modern healthcare it’s typically used interchangeably with vaccinate (though it’s used less commonly). Immunize is slightly different—it means to provide 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 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. Want to learn more? Read the full breakdown of the difference between immunize, vaccinate, and inoculate.

Other Word Forms

Derived Forms

• immunization
  noun
• immunizer
  noun
• hyperimmunize
  verb (used with object)
• overimmunize
  verb (used with object)

Inflected Forms

Participles

• immunizing
  present
• immunized
  past

Conjugated Forms

Present

• immunize
  simple
• immunizes
  simple
• have immunized
  perfect
• has immunized
  perfect
• am immunizing
  progressive
• are immunizing
  progressive
• is immunizing
  progressive
• have been immunizing
  perfect progressive
• has been immunizing
  perfect progressive

Past

• immunized
  simple
• had immunized
  perfect
• was immunizing
  progressive
• were immunizing
  progressive
• had been immunizing
  perfect progressive

Future

• will immunize
  simple
• will have immunized
  perfect
• will be immunizing
  progressive
• will have been immunizing
  perfect progressive

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Etymology

Origin of immunize

First recorded in 1890–95; immune + -ize

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Explanation

To immunize someone is to give them a vaccine that protects them against disease. A child's pediatrician can immunize her against measles, polio, and mumps, among many other illnesses. Vaccines work by arming your immune system against being infected — in other words, they produce immunity, or immunize you. In some cases, being exposed to a disease can also immunize you; if you've had chicken pox, you are most likely immune to it and won't get it again. There is also a legal meaning of immunize, "To make legally immune," or "to protect from being prosecuted in court." The Latin root, immunis, means "exempt" or "free."

Example Sentences

See Examples For:

immunize immunizes immunized immunizing

Unfortunately for the bulls, robust projected earnings growth doesn’t immunize the market from major declines.

From MarketWatch ● Jan. 13, 2026

You can think of many areas where merely sitting abroad is not going to immunize you from the reach of American prosecution.

From Slate ● Jan. 7, 2026

After Epstein’s death, the men used their executor roles—controlling both victims’ compensation and access to records—to try to immunize themselves from personal lawsuits, according to court filings.

From The Wall Street Journal ● Nov. 23, 2025

But RSV, the leading cause of infant hospitalization nationwide, presents particular risk for the youngest babies, a major reason health experts recommend pregnant women either get vaccinated near their delivery date or immunize their newborns.

From Los Angeles Times ● Oct. 30, 2025

I knew what a photograph was, and I had been examined by a doctor once, an African doctor, but I didn’t know what the word immunize meant.

From "Taking Flight: From War Orphan to Star Ballerina" by Michaela DePrince

But her efforts to hold the prosecutor accountable have run into a roadblock at the state’s highest court, which says longstanding court doctrine immunizes prosecutors from civil liability.

From Seattle Times ● Jun. 21, 2023

He has argued that the Constitution’s “speech or debate” clause, which shields members of Congress from reprisals for legislative conduct, immunizes him against testifying because the vice president serves as president of the Senate.

From Los Angeles Times ● Mar. 30, 2023

Tech companies argue they are protected by Section 230 of the Communications Decency Act, which in general immunizes them from liability for content someone else has posted.

From Washington Times ● Feb. 17, 2023

If Omicron safely immunizes people and similarly recombines with and tames more pathogenic SARS-CoV-2 variant, that would be “a best-case scenario,” she says.

From Science Magazine ● Feb. 4, 2022

In some we observe that the carrier results from a low-level, incomplete infection with the disease which immunizes him but does not kill the bugs.

From Highways in Hiding by George Oliver Smith

To achieve herd immunity, a level of vaccination that protects those who can’t get shots, a community needs around 95% of people to be immunized.

From The Wall Street Journal ● Sep. 4, 2026

Norway, by contrast, after the discovery of North Sea oil in the 1970s, set up a sovereign-wealth fund through a trust structure independent of central government and thus immunized against political manipulation.

From MarketWatch ● Jul. 6, 2026

Those who are not immunized or are unsure of their status should monitor themselves closely for signs of infection.

From Los Angeles Times ● Feb. 19, 2026

People who aren’t fully immunized should contact a healthcare provider if exposure happened less than a week ago, according to the release.

From Los Angeles Times ● Feb. 2, 2026

I thought maybe my age, or the presence of the Red Cross, immunized me against the terrors I knew existed in the camp.

From "Internment" by Samira Ahmed

Public-health experts have warned against delaying the vaccine or only immunizing the babies of infected women at birth.

From The Wall Street Journal ● Dec. 5, 2025

But immunizing cows would curb the risk to farm workers, and to other cows, and limit the opportunities for the virus to keep spreading and evolving, experts said.

From New York Times ● Jun. 17, 2024

Healing, renewing, and then immunizing American democracy against such forces will be a decades-long social and political project.

From Salon ● Dec. 20, 2023

The CDC also recommends the Abrysvo vaccine for pregnant people and immunizing babies against RSV with an antibody known as nirsevimab, also known by the trademarked name Beyfortus.

From Los Angeles Times ● Dec. 16, 2023

She is given a list of pediatricians, and coundess brochures on breast-feeding, and bonding, and immunizing, and samples of baby shampoos and Q-Tips and creams.

From "The Namesake" by Jhumpa Lahiri

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Related Words

• inoculate
• protect
• vaccinate

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