Webster old definition: “A preparation of killed microorganisms, living attenuated organisms or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease’”

Webster new definition:” ‘a preparation that is administered (as by injection) to stimulate the body’s immune responses against a specific infectious agent or disease: such as a: an antigenic preparation of a typically inactivated or attenuated pathogenic agent (such as a bacterium or virus) or one of its components or products (such as a protein or toxin)’

: 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) … Moderna's coronavirus vaccine … works by injecting a small piece of mRNA from the coronavirus that codes for the virus' spike protein. … mRNA vaccine spurs the body to produce the spike protein internally. That, in turn, triggers an immune response.