Active immunization is the induction of immunity after exposure to an antigen. Antibodies are created by the recipient and may be stored permanently.
Active immunization can occur naturally when a microbe or other antigen is received by a person who has not yet come into contact with the microbe and has no pre-made antibodies for defense. The immune system will eventually create antibodies for the microbe, but this is a slow process and, if the microbe is deadly, there may not be enough time for the antibodies to begin being used.
Artificial active immunization is where the microbe is injected into the person before they are able to take it in naturally. The microbe is treated, so that it will not harm the infected person. Depending on the type of disease, this technique also works with dead microbes, parts of the microbe, or treated toxins from the microbe.
Famous quotes containing the word active:
“There is not enough exercise in this way of life. I try to make up by active gymnastics before I dress when I get up, by walking rapidly in the lower hall and the greenhouse after each meal for perhaps five to ten minutes, and a good hand rubbing before going to bed. I eat moderately; drink one cup of coffee at breakfast and one cup of tea at lunch and no other stimulant. My health is now, and usually, excellent.”
—Rutherford Birchard Hayes (1822–1893)