The concern relates to the overuse of vaccines in these immunologically naive
youngsters and adult dogs and cats, as well as to vaccines given to aged pets
and those with already compromised immune systems. This is when you, as your
companion animal’s trusted guardian, should understand what is appropriate and
put the breaks on giving unnecessary vaccines.
Let’s take a look at the two types of vaccines – modified live-virus vaccines
(MLV) and killed vaccines – and their potential effects on your pet’s
health.
MLV vaccines[/b]
As the name suggests, MLV vaccines use a modified, but weakened, form of the
live microorganism. When the virus is injected into the body, it multiplies
many-fold and stimulates the immune system’s production of antibodies, creating
an immune response that protects the body against future exposure to the
disease.
For dogs: Distemper virus, adenovirus-2 (hepatitis, canine respiratory virus)
and parvovirus are all MLV canine vaccines, as are intranasal bordetella,
intranasal coronavirus (not recommended by 2011 AAHA* Canine Vaccine
Guidelines), and parainfluenza virus. The first three vaccines plus rabies
vaccine are the so-called “core” vaccines for dogs. (Note: a recombinant canine
distemper virus vaccine is also available.)
[color=darkred] MLV vaccines have been associated with
the development of temporary seizures in both puppies and adult dogs of breeds
or crossbreeds susceptible to immune-mediated diseases – especially those
involving hematologic or endocrine tissues such as immune-mediated/autoimmune
hemolytic anemia (IMHA/AIHA), immune/idiopathic thyrombocytopenic purpura (ITP),
a low platelet count and autoimmune thyroiditis. MLV vaccines – given singly or
in combination – are also increasingly recognized contributors (albeit rarely)
to immune-mediated blood disease, bone marrow failure and organ
dysfunction. When MLV vaccines are given to pets with
compromised immune systems, the animal is actually at risk of contracting a
weakened form of the virus from the vaccine. [/color]
The introduction of MLV vaccines more than 20 years ago is linked to
increasing allergic problems and immunological disease in companion animals.
Dogs with pre-existing inhalant allergies (atopy) to pollens display an
increased risk of vaccinosis (an adverse vaccine response).
Killed vaccines[/b]
Killed vaccines use an inactivated “ dead” form of the virus (previously live
microorganisms that have been killed with chemicals or heat), along with an
adjuvant (a substance added to a vaccine to enhance its effectiveness without
itself causing an immune response).
For dogs: Killed vaccines include all rabies vaccines, canine leptospirosis,
Lyme, canine influenza, injectable bordetella, injectable coronavirus (not
recommended by 2011 AAHA* Canine Vaccine Guidelines) and diamondback rattlesnake
toxoid (does not protect equally against all types of rattlesnakes, including
Mohave green variety).
For cats: Unlike canine vaccines, most vaccines for cats come in MLV (not
recommended for pregnant queens or very young kittens), killed and intranasal
versions. Vaccines for feline panleukopenia virus (a parvovirus, often
incorrectly called feline distemper), feline viral respiratory disease complex
(feline herpes virus and calicivirus) plus rabies vaccine are considered as
“core” feline vaccines. Killed and so-called ‘lifestyle’ (see below) vaccines
also include those for feline leukemia virus (a recombinant version is also
available), feline immunodeficiency virus, chlamydia and intranasal bordetella
(these latter two are not recommended for routine use).
[color=darkred] As with MLV vaccines, killed vaccines can
trigger both immediate and delayed adverse reactions. Of highest concern are the
vaccine injection-site sarcomas most commonly seen after rabies vaccination in
cats, but also seen occasionally in dogs.[/color] Genetic predisposition
to these disorders in humans has been linked to the leucocyte antigen D-related
gene locus of the major histocompatibility complex, and is likely to have
parallel associations in domestic animals. Killed vaccines can at worst
aggravate an already existing autoimmune disease and may prove ineffective.
Although all dogs are susceptible to vaccine-related side effects, breeds at
highest-risk of vaccinosis (in alphabetical order) are:
• Akita
• American Cocker Spaniel
• German Shepherd
• Golden
Retriever
• Irish Setter
• Great Dane
• Kerry Blue Terrier
•
Dachshunds (all varieties, but especially the long-haired)
• Poodles (all
varieties, but especially the Standard Poodle
• Old English Sheepdog
•
Scottish Terrier
• Shetland Sheepdog
• Shih Tzu
• Vizsla
•
Weimaraner
Breeds with white or predominantly white coats, as well as those with coat
color and pigment dilution such as fawn (Isabella) or blue Dobermans, the merle
coat color, blue Yorkshire Terriers, grey Collies, harlequin Great Danes, and
Australian Shepherds are also more susceptible.
Note: Breed-susceptibility data are generally unavailable for vaccinosis in
cats.
People often ask me about the non-core vaccines, such as leptospirosis, Lyme
disease, bordetella (a component of kennel cough) and canine influenza. These
vaccines are considered “lifestyle” vaccines and should be assessed according to
your dog’s individual risk factors. Does your dog play at a dog park with other
animals? Is he boarded in a kennel? Does he attend doggy daycare? Does your
geographic location have increasing outbreaks or incidences of a particular
disease? All of these factors should come into play when deciding whether to
vaccinate your pet against the lifestyle vaccines. Most non-core vaccines
require annual revaccination to maintain immunity, so be sure that your dog
really needs them.