vaccine

vaccine

Preparation containing either killed or weakened live microorganisms or their toxins, introduced by mouth, by injection, or by nasal spray to stimulate production of antibodies against an infectious agent. This confers immunity to that agent, since the B lymphocytes remain sensitized to it and respond to later infection by producing more antibodies. The first vaccine, against smallpox, was introduced by Edward Jenner in 1798. Vaccines have been developed against diseases caused by bacteria (e.g., typhoid, whooping cough, tuberculosis) and by viruses (e.g., measles, influenza, rabies, poliomyelitis). Effectiveness varies, and a small percentage of people have adverse reactions. Those with immunodeficiency disorders should not receive live vaccines.

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vaccine Med

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. of or relating to vaccination or vaccinia

4. Computing a piece of software designed to detect and remove computer viruses from a system

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vaccine [vak′sēn]

(immunology)

A suspension of killed or attenuated bacteria or viruses or fractions thereof, injected to produce active immunity.