|a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.|
|the offspring of a zebra and a donkey.|
|1.||a suspension of dead, attenuated, or otherwise modified microorganisms (viruses, bacteria, or rickettsiae) for inoculation to produce immunity to a disease by stimulating the production of antibodies|
|2.||(originally) a preparation of the virus of cowpox taken from infected cows and inoculated in humans to produce immunity to smallpox|
|3.||(modifier) of or relating to vaccination or vaccinia|
|4.||computing a piece of software designed to detect and remove computer viruses from a system|
|[C18: from New Latin variolae vaccīnae cowpox, title of medical treatise (1798) by Edward Jenner, from Latin vacca a cow]|
vaccine vac·cine (vāk-sēn' vāk'sēn')
A preparation of a weakened or killed pathogen, such as a bacterium or virus, or of a portion of the pathogen's structure that upon administration stimulates antibody production against the pathogen but is incapable of causing severe infection.
A vaccine prepared from the cowpox virus and inoculated against smallpox.
|vaccine (vāk-sēn') Pronunciation Key
A preparation of a weakened or killed pathogen, such as a bacterium or virus, or of a portion of the pathogen's structure, that stimulates immune cells to recognize and attack it, especially through antibody production. Most vaccines are given orally or by intramuscular or subcutaneous injection. See Note at Jenner.
Our Living Language : In the 1950s, polio epidemics left thousands of children with permanent physical disabilities. Today, infants are given a vaccine to prevent infection with the polio virus. That vaccine, like most others, works by stimulating the body's immune system to produce antibodies that destroy pathogens. Scientists usually prepare vaccines by taking a sample of the pathogen and destroying or weakening it with heat or chemicals. The inactivated or attenuated pathogen loses its ability to cause serious illness but is still able to stimulate antibody production, thereby conferring immunity. The Salk polio vaccine contains "killed" virus, while the Sabin polio vaccine contains weakened "live" poliovirus. (Many scientists no longer consider viruses to be living organisms) Scientists are also able to change the structure of viruses and bacteria at the molecular level, altering DNA so that the potential of the vaccine to cause disease is decreased. New vaccines containing harmless bits of DNA have also been developed.