Substance used to stimulate the production of antibodies and provide immunity against one or several diseases,agent of a disease, its products, or a synthetic substitute
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. Wikipedia