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© 1986, The Board of Regents of the University of Nebraska on behalf of the University of Nebraska–Lincoln Extension. All rights reserved.


This NebGuide discusses reasons why vaccinations fail to provide immunity against disease, and how to prevent this from happening.

To comprehend the many reasons for vaccine failure, it is important to understand how animals and humans have the ability to resist infectious diseases. It is also important to know what a disease is and how it affects the animal.

According to Stedman's Dictionary, disease is an interruption, cessation or disorder of body functions, systems or organs. Diseases may be obvious even to the untrained eye, or detectable only by sophisticated testing procedures (subclinical disease). Serious irreversible damage may be done even at the subclinical level if therapeutic or preventive measures are not taken early.