vaccinate

American  

[vak-suh-neyt] / ˈvæk səˌneɪt /

verb (used with object)

vaccinated, vaccinating

1. to inoculate with the vaccine of cowpox so as to render the subject immune to smallpox.

2. to inoculate with the modified virus of any of various other diseases, as a preventive measure.

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verb (used without object)

vaccinated, vaccinating

1. to perform or practice vaccination.

vaccinate British  

/ ˈvæksɪˌneɪt /

verb

1. to inoculate (a person) with a vaccine so as to produce immunity against a specific disease

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Usage

What’s the difference between vaccinate, inoculate, and immunize? In the context of medicine, vaccinate, inoculate, and immunize 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 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. Want to learn more? Read the full breakdown of the difference between vaccinate, inoculate, and immunize.

Other Word Forms

• prevaccinate verb (used with object)
• revaccinate verb (used with object)
• unvaccinated adjective
• vaccinator noun

Etymology

Origin of vaccinate

First recorded in 1800–10; back formation from vaccination

Explanation

To vaccinate is to immunize someone against a disease. Babies are usually vaccinated against many diseases soon after birth. A vaccine is a type of medicine that makes you resistant (immune) to a disease like polio. To give someone such a medicine is to vaccinate them. You can use this word in a few ways. A doctor is usually the person who vaccinates a child (or older person) by administering a vaccine. You can also say the parents have vaccinated their children by making the decision to do so. Animals can be vaccinated too, like dogs are vaccinated against rabies.

Example Sentences

In February, an outbreak of measles in some schools in north London prompted health authorities to remind parents to vaccinate their children.

From BBC • Apr. 6, 2026

South Africa in January rolled out a 10-year drive to vaccinate 20 million cattle against the disease in an outbreak Steenhuisen described as the "worst ever".

From Barron's • Feb. 4, 2026

Centers for Disease Control and Prevention spoke with a single voice when advising the nation’s families on when to vaccinate their children.

From Los Angeles Times • Jan. 26, 2026

“All of our best studies and decades of experience point to continuing to vaccinate all newborns to protect them against hep B.”

From Salon • Dec. 12, 2025

We imagined them liberating Angola and marching right on up the Congo River to vaccinate us all!

From "The Poisonwood Bible" by Barbara Kingsolver

Related Words

• immunize
• inject
• inoculate
• protect
• treat