Inoculation of a substance (
vaccine) into the body for the purpose of producing active
immunity against a disease. The
vaccine is usually a weakened culture of the agent causing the disease; the use of vaccines is a cornerstone of preventive medicine. Vaccination was used in ancient times in China, India and Persia, and was introduced to the West in the late 18th century by E. Jenner. Vaccinations have eradicated smallpox and are used today to prevent diphtheria, poliomyelitis, rabies and typhoid. Experimental vaccines for certain cancers have been developed for laboratory mice. See also
Inoculation.