n. a means of producing immunity to a disease by using a *vaccine, or a special preparation of antigenic material, to stimulate the formation of appropriate antibodies. The name was applied originally only to treatment with vaccinia (cowpox) virus, which gives protection not only against cowpox itself but also against the related smallpox. However, it is now used synonymously with inoculation as a method of *immunization against any disease. Vaccination is often carried out in two or three stages, as separate doses are less likely to cause unpleasant side-effects. A vaccine is usually given by injection but may be introduced into the skin through light scratches; for some diseases (such as polio), oral vaccines are available.
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