Causes of Vaccination-Immunization Failures in Livestock
This NebGuide discusses reasons why vaccinations fail to provide immunity
against disease, and how to prevent this from happening.
Duane Rice, DVM, Extension Veterinarian
E. Denis Erickson, DVM, Veterinary Microbiologist
Dale Grotelueschen, DVM, Extension Veterinarian
a.. The Causes of Disease
b.. Resistance to Infectious Agents
c.. Factors Associated with the Animal
d.. Factors Associated with the Antigen (Vaccine)
e.. Factors Associated with Handling Vaccine
f.. Other Factors
g.. Vaccination in the Face of an Outbreak
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
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.
The Causes of Disease
These may be categorized in two types:
1.. Nonliving, such as chemical poisons (toxins), or excessive heat or
2.. Living, which includes infectious agents (pathogens), viruses,
bacteria (which may themselves produce toxins), and large parasites such as
lice and worms.
Resistance to Infectious Agents
Resistance can also be divided into two types:
1.. Nonspecific or innate resistance--resistance that is present in the
normal animal prior to infection.
2.. Specific immune resistance--resistance that arises only after repeated
exposure to the agent.
This type includes natural barriers such as the skin, the washing effect by
secretions such as tears, and certain normal responses such as coughing.
Each is a part of the individual from birth, but may be significantly
affected by hereditary, nutritional, and environmental influences.
Specific "Immune" Resistance
This type usually arises following exposure of the animal (particularly the
white blood cells in the animal) to the infectious agent (an antigen). This
exposure can come about during an actual (natural) infection, or
artificially by inoculation of the animal with the infectious agent, which
has been killed or made nonpathogenic. This procedure is called vaccination.
In most cases the animal will respond to the vaccine (antigen) by producing
immune bodies called antibodies, and will stimulate production of more white
blood cells that react specifically with the inciting agent (vaccine).
Occasionally an animal does not respond sufficiently to provide protection.
Such animals, in spite of vaccination, have failed to become immune--they
are not immunized. Many factors can affect the development of immunity in
the individual, and contribute to apparent failures in vaccine protection.
The remainder of this NebGuide provides some reasons for such failure.
Factors Associated with the Animal
The very young animal has not had time to develop a competent immune system.
On the other hand, the very old animal may have various deficiencies in
Young animals that have received colostrum have also received large
quantities of antibodies from their dam. High levels of these passively
acquired antibodies can interfere with the development of the young animal's
own immune response to vaccines for 1 to 2 months or longer.
Some animals, due to heritable traits, respond less than the normal
population does to antigens either through vaccination or natural infection.
Even though they have been inoculated with the vaccine, they may not become
Animals deficient in nutrients may respond poorly to vaccines, as well as
being below their genetic production potential.
Interference Due to Concurrent Disease
Certain diseases, if present at the time of vaccination, may prevent an
adequate immune response to the vaccine.
Protection against infection of newborn animals is best obtained by passive
transfer of antibodies from the dam. Some vaccines are given to the dam in
anticipation that she will transfer specific preformed antibodies to her
young. These are passively acquired antibodies that are effective for only
one to two months in the offspring. However, if she does not respond with
adequate antibody levels, or if her offspring do not suckle adequately in
the first 12 hours of life, there may be a failure to transfer antibodies to
When the antibody level within an animal is present due to maternal or other
passive immunity, the antigenic properties of vaccine can be neutralized and
no immunity develops. As the passive antibody levels wane, the animal may
then have no protection because the vaccine used earlier was inhibited by
the very antibody that is now depleted.
Poor nutrition, shipping, crowding, and other stressful events may produce
hormonal or chemical imbalances in the animal that suppress the immune
system and its response to vaccines.
Factors Associated with the Antigen (Vaccine)
The immune response is very specific. A vaccine may contain organisms of the
same family as those involved in a disease outbreak, but if they are not of
the same serotype (type within the family), the results may be
Potency and Purity
Vaccines must have adequate antigenic mass to properly stimulate an immune
response. Vaccines not made under strict controls may not have this
capability. Purity is also an important factor as contamination may render
the vaccine worthless by destroying antigenic properties. Other adverse
effects may include abscess development at the site of inoculation, or the
introduction of an entirely different disease problem.
Outdated vaccine may not contain the required antigenic properties due to
deterioration or other factors. It is not worth taking a chance that it may
work. The investment to obtain fresh, quality vaccine far outweighs the
possibility of losing just one animal due to poor vaccine.
All vaccines have limitations. Some vaccines for certain diseases
occasionally do not cause production of enough immunity at both the local
and systemic levels to give adequate protection against that disease.
Alternate routes of administration and/or boosters are sometimes used to
help alleviate this problem. We must not expect more than the vaccine
Factors Associated with Handling Vaccine
It is imperative that vaccines be stored and used exactly as directed by the
manufacturer. Exposure to sunlight, chemicals, drugs, and adverse
temperatures may destroy the vaccine's effectiveness. Vaccine that requires
mixing should always be used promptly. Sources of purchase of vaccine should
be evaluated to help determine if proper care was provided before purchase.
Mixing vaccines properly is a "must" as the "antigenic mass," or dosage, is
calibrated to produce antibody levels that are protective. Modified live
virus (MLV) vaccines must be reconstituted properly, using the diluent
supplied for that vaccine in the correct quantity. Administer vaccine only
from sterile syringes that have been sterilized without the use of
chemicals. Never mix other vaccine types together when not specifically
recommended by the manufacturer, as chemical incompatibility is possible.
Timing of Vaccinations
The correct timing of vaccine administration is absolutely necessary to
expect a reasonable immune response. Time to build protection, time in
relation to animal age, and the time when most resistance to the disease is
needed are some of the factors you must consider.
Waning of Immune Status
Immune status can wane to the point of susceptibility when exposure to
antigenic material is minimal or absent. For this reason, some manufacturers
recommend using a booster vaccination to build a higher antibody level. When
the manufacturer's directions recommend a booster, it is necessary that it
be done at the recommended intervals. Frequently the first dose only
sensitizes the immune system; the second dose is necessary to develop a high
This can occur when excessive animal stress combines with entrance of
extremely large numbers of virulent disease-causing organisms. This
overwhelming infection can overcome even a relatively strong immune
Mechanics of Vaccination
At the time the vaccine is administered, strict attention to details is very
important to prevent "misses." Animals can be missed at vaccination time
when too many jobs are being done simultaneously. Organization is very
important. Escape-proof pens or corrals and other methods to reduce the
"missed ones" are also very important.
Route of Administration
Companies that produce vaccine will specifically label the route of
administration and which site of inoculation is preferred. Research by the
manufacturer has proven which route is best. If injection in the muscle is
specified, the vaccine should not be given by any other route. Your
veterinarian should be involved to ensure proper vaccine selection and use.
Precautions should be taken to ensure the physical well-being of the animal.
In addition to vaccine recommendations, precautions should be followed so as
not to mechanically damage nerves, joints, or other body parts with the
needle. This includes paying attention not only to the area of the animal
injected, but also such things as length and gauge of the needle.
Vaccination in the Face of an Outbreak
All commercially manufactured vaccines are formulated and labelled to be
used only on healthy animals. Vaccinating animals in the face of an outbreak
would generally be unadvisable as relatively high numbers of these animals
would be sick, under stress, and would not be "healthy" at that time. These
conditions contribute to vaccine failure.
The causes of vaccine failure are numerous, but if precautions are taken as
described in this NebGuide, the "vaccine failures" that occur can be greatly
reduced and disappointing livestock losses can be avoided. The best
procedure in using vaccines is to CONSULT YOUR VETERINARIAN AND FOLLOW THE
File G797 under: ANIMAL DISEASES
F-4, General Livestock
Issued May 1986; 12,000 printed.
Electronic version issued January 1997
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June
30, 1914, in cooperation with the U.S. Department of Agriculture. Kenneth R.
Bolen, Director of Cooperative Extension, University of Nebraska, Institute
of Agriculture and Natural Resources.