COBTA concluded that evidence shows that some vaccines provide immunity beyond one year. While annual vaccinations have been highly
successful in curbing disease, the one-year revaccination frequency recommendation found on many vaccine labels is based on historical
precedent, not scientific data. Even in cases where scientific data were submitted to qualify a label claim, the data generated generally
represent a minimum duration of immunity and don't resolve the question about average or maximum duration of immunity.
Vaccination Principles
The one-year revaccination recommendation found on many vaccine labels is often based on historical precedent and was allowed by USDA
regulation since it was based on the best scientific knowledge available at that time, which did not necessarily include product specific
data. Even in those cases where scientific data were submitted to qualify a revaccination label claim, the data generally targeted a
minimum duration of immunity and did not necessarily resolve the question regarding average or maximum duration of immunity ...
Vaccination is a potent medical procedure with both risks and benefits. While there is evidence that some vaccines provide immunity
beyond one year, revaccination of patients with sufficient immunity does not necessarily add to their disease protection and may increase
the potential risk of post-vaccination adverse events ... Adverse events may be associated with the antigen, adjuvant, carrier,
preservative, or a combination thereof. Possible adverse events include, but are not necessarily limited to, failure to immunize,
anaphylaxis, immuno-suppression, autoimmune disorders, transient infections, long-term infected carrier states, and local development of
tumors. The role of genetic predisposition to adverse events needs further exploration and definition ... Vaccine program goals include
providing optimal immunity against clinically relevant diseases the patient is at-risk to contract, while minimizing the potential for
adverse events ... Unnecessary stimulation of the immune system does not necessarily result in enhanced disease resistance, and may increase
the potential risk of post-vaccination adverse events Š.. Disease carriers, including animals that shed infectious agents but do not necessarily
show signs of illness, are sources of infection for susceptible animals. Sufficient immunity within a population of animals is an important
component of preventing disease prevalence. Programs targeting immunization of susceptible animals are critical to disease control ...
Vaccination protects a population of animals by providing a level of resistance to a disease in those individual patients that are able to
respond. Vaccination does not protect every individual patient even when they are properly vaccinated.
There is a critical need for more fully developed, scientifically based, and statistically valid evaluation of vaccine products to provide
practitioners with a basis for developing vaccination programs that maximize benefits and minimize associated risks for the patients under
their care.
Vaccination is a potent medical procedure associated with both benefits and risks for the patient. Adverse events, including some that are
potentially severe, can be unintended consequences of vaccination.
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