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Vaccine Definition

VACCINE A vaccine is a toxic substance consisting of live or dead bacteria or viruses or of the toxic products of bacteria or viruses, which if inoculated in a person will immunize that person against a particular disease. A vaccine, when inoculated, will usually cause some reaction in the inoculated or vaccinated person, but this mild reaction produces enough antibodies in his blood to protect him from the disease.

The immunity conferred by a vaccination is of much longer duration than that produced by the injection of an anti serum or antitoxin. Smallpox vaccination is an example of vaccine inoculation. Serum globulin injection against measles or tetanus antitoxin against lockjaw is an example of the latter.

The toxic substance of a bacterium or virus is called antigen. When antigens get into the blood they call forth anti bodies which fight and neutralize the toxic antigens, thus helping the white blood cells to destroy the bacteria.

Vaccines are sometimes made of live bacteria which have become "attenuated" or weakened by repeated culturing under unfavorable conditions. These resulting generations of bacteria lose their virulence or become inactive—half dead, so to speak—and will not produce the disease they were wont to produce.

But while they cannot cause the disease, they do call forth antibodies when inoculated into an animal or human being. Vaccines are sometimes prepared from the bacteria taken from a patient suffering from an infectious disease for the purpose of inoculating him and thus stimulating antibody formation against his disease.

A vaccine so made is called an autogenous vaccine, i.e., "self-produced." Vaccines made of attenuated bacteria are not always safe because when bacteria find themselves in new and favorable conditions (and the human body seems a favorite with them) they take on new life and virulence, and the vaccine may aggravate the patient instead of doing him good.

When the American people will be educated to it and will have the means to live under the best hygienic and sanitary conditions, there will be no need of vaccines and vaccinations

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