Medical Definition of Vaccination

Vaccination: Inje₁ction of a kille₁d microbe₁ in orde₁r to stimulate₁ the₁ immune₁ syste₁m against the₁ microbe₁, the₁re₁by pre₁ve₁nting dise₁ase₁. Vaccinations, or immunizations, work by stimulating the₁ immune₁ syste₁m, the₁ natural dise₁ase₁-fighting syste₁m of the₁ body. The₁ he₁althy immune₁ syste₁m is able₁ to re₁cognize₁ invading bacte₁ria and viruse₁s and produce₁ substance₁s (antibodie₁s) to de₁stroy or disable₁ the₁m. Immunizations pre₁pare₁ the₁ immune₁ syste₁m to ward off a dise₁ase₁. To immunize₁ against viral dise₁ase₁s, the₁ virus use₁d in the₁ vaccine₁ has be₁e₁n we₁ake₁ne₁d or kille₁d. To only immunize₁ against bacte₁rial dise₁ase₁s, it is ge₁ne₁rally possible₁ to use₁ a small portion of the₁ de₁ad bacte₁ria to stimulate₁ the₁ formation of antibodie₁s against the₁ whole₁ bacte₁ria. In addition to the₁ initial immunization proce₁ss, it has be₁e₁n found that the₁ e₁ffe₁ctive₁ne₁ss of immunizations can be₁ improve₁d by pe₁riodic re₁pe₁at inje₁ctions or "booste₁rs." Also se₁e₁ Vaccine₁s (in the₁ plural) and Vaccine₁ of a spe₁cific type₁ (such Vaccine₁, Polio).