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

Etymology

Origin of immunize

First recorded in 1890–95; immune + -ize

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

It suggests that no other irreversible power to immunize lurks in the Constitution’s silences.

From Slate ● May 26, 2026

Per the researchers’ formula, therefore, holding this ETF for between 10 and 11 years should immunize it from interest rate hikes.

From MarketWatch ● May 22, 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

And I volunteer at the clinic, where a Guinean doctor comes once a week from Coquilhatville to immunize and diagnose babies.

From "The Poisonwood Bible" by Barbara Kingsolver

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

This means that even minor factual differences between the case at issue and prior cases effectively immunizes the officer from accountability.

From Washington Post ● Mar. 20, 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 Smith, George Oliver

“It’s a virus that mutates and against which people must be immunized over and over again.”

From The Wall Street Journal ● Jul. 8, 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

And very significantly, even if the president is fully immunized against damages, his associates are not.

From Slate ● May 21, 2025

“Measles is so infectious,” said Dr. Chad Vercio, division chief of general pediatrics at Loma Linda University Children’s Health in San Bernardino County, where about 93.5% of kindergarten students were immunized against measles last year.

From Los Angeles Times ● Mar. 19, 2025

It immunized your body and your soul, and that was why she ignored us kids when we cried.

From "The Glass Castle" by Jeannette Walls

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

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

The contracts specify that the vaccines can only be used for immunizing humans and violations in theory could create liability issues for the companies.

From Science Magazine ● May 30, 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

Related Words

• inoculate
• protect
• vaccinate