Vaccine (noun)

1. A substance or treatment that stimulates the production of immunity to a disease, typically by introducing a small quantity of the disease agent into the body.
2. A preparation of dead or weakened microorganisms or toxins, or of antibodies or antiserum, introduced into the body to produce immunity to a specific disease.

Origin:

Late 17th century: from latin vaccīnus, from vaccīna "cow pox", from vacca "cow".

Examples:

1. The vaccine against the new virus is being distributed around the world.
2. Due to the low vaccine coverage, the disease spread quickly.
3. My grandma went to the doctor to get a flu vaccine.
4. The vaccine is considered one of the most important medical discoveries of all time.
5. Vaccination has greatly reduced the number of cases of many diseases.