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Lately, much controversy concerning
vaccination
and over-vaccination has been in the news. This
has been due to a fairly recent discovery relating vaccine
administration in cats to subsequent occurrence of tumor
at the site of the vaccination.
The incidence of occurrence of tumors in cats from
vaccine is low; less than 5 percent of the cat population
vaccinated develop tumor at the site of vaccination.
The tumor known as Fibrosarcoma, is a malignant
tumor, meaning it grows uncontrollably and spreads fairly
rapidly. Usually, this tumor does not metastasize,
meaning that it does not spread to distant sites from
its original location. However, it is very aggressive
locally, and unless caught early, and surgically removed
completely, regrowth will occur with a vengeance.
It is now thought that the part of the vaccine which
acts to promote the affect of the virus being vaccinated
for, known as the adjuvant, may be the cause of tumor
formation. Still much controversy and study into
this matter is underway, trying to determine if one
cause or more than one cause for the tumor formation
exists.
Cats appear to be the only species to date affected
by this abnormal tumor reaction from vaccination; none
has yet to be reported to occur in other species.
Two vaccines have been implicated in the cause of fibrosarcoma
formation in the cat: the leukemia virus vaccine, and
the rabies vaccine. Some vaccine manufacturers
have developed rabies vaccine which will create immunity
over a 3 year period. This decreases then the
annual frequency of vaccine administration for the rabies
vaccine, thus decreasing the chance of tumor formation
by reducing the frequency of vaccination.
Cats who normally are inside only, with little contact
with outdoors or patios, and no contact with other cats
even through screen enclosures, are usually protected
from feline leukemia and rabies viruses. However,
by law in most states, rabies vaccine must be administered
to all pets in a household.
Recently, a vaccine known as Purevax has been
manufactured for rabies which contains no adjuvant.
Frequency of administration is annually, yet the risk
of vaccine induced tumor from an adjuvant has been removed.
Check with your veterinarian, or submit your request
to Questions
for the vet to determine what may be the
best recommendation for vaccination protocol for your
pet.
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