vaccination (vaksinashon)

[= F. vacci nation = Sp. vacunacion = Pg. vaccinação = It. vaccinazione; as vaccinate + -ion.] In med., inoculation with vaccine, or the virus of cowpox, as a preventive of smallpox; in an extended sense, inoculation with the virus of any specific disease. The utility of vaccination with the virus of cowpox was discovered by Edward Jenner, an English surgeon, in the latter part of the eighteenth century, the first vaccination upon the human subject having been made in 1796. It consists in the introduction under the skin, or application to an abraded surface, usually on the upper arm or thigh, of a minute quantity of vaccine. This is followed, in a typical case, in about two days, by slight redne and swelling at the point of inoculation, and on the third or fourth day by the appearance of a vesicle filled with clear fluid, and umbilicated or depre ed in the center. About the end of the eighth day a ring of inflammation, called the areola, begins to form around the base of the vesicle; it is usually hard, swollen, and painful. On the eleventh or twelfth day the inflammation begins to subside; the ves turns yellow, up and a or 6682