A shot you get that is intended to make you immune to catching the measles is an example of a vaccine.
Origin of vaccine
- From Latin vaccīnus of cows from vacca cow
From American Heritage Dictionary of the English Language, 5th Edition
- From Latin vaccinus, from vacca (“cow") (because of early use of the cowpox virus against smallpox). Cf. New or Scientific Latin (variola) vaccÄ«na, or "cowpox".