noun

vaccine

/vækˈsiːn/ · say it: vak·SEEN

a preparation that trains the immune system against a disease

In Medicine & Health

In more detail

1. (noun) a substance given to people or animals to help their body fight a disease by building immunity to it

2. (noun) an injection or dose of this substance

Examples

1. The vaccine protects children from measles and mumps.
2. She received her first vaccine against COVID-19 last month.

How to use vaccine

Vaccine is a neutral, technical term used in medical and public health contexts to refer to preparations that trigger immune responses. It is more formal than informal alternatives like jab or shot, though all are widely used. The term emphasizes the biological substance itself, while vaccination emphasizes the act of administering it.

Common phrases

administer a vaccine
receive a vaccine
vaccine rollout
vaccine efficacy
vaccine hesitancy
vaccine mandate

Synonyms

immunization · inoculation · jab · shot · dose

Word family

vaccinate (verb) · vaccination (noun) · vaccinated (adjective) · vaccine-preventable (adjective)

A common mistake

Learners sometimes confuse vaccine (the substance) with vaccination (the process of giving the vaccine), or use them interchangeably when precision matters.

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