Definition of vaccine
: a preparation that is administered (as by injection) to stimulate the body's immune response against a specific infectious disease:
a
: an antigenic preparation of a typically inactivated or attenuated (see attenuated sense 2) pathogenic agent (such as a bacterium or virus) or one of its components or products (such as a protein or toxin)
b
: a preparation of genetic material (such as a strand of synthesized messenger RNA) that is used by the cells of the body to produce an antigenic substance (such as a fragment of virus spike protein)
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Merriam-Webster unabridged
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Time Traveler for vaccine
The first known use of vaccine was in 1882
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