Dr. Jean Dodds' Pet Health Resource Blog | A Pilot Study: 1/2 Dose Vaccines for Small Dogs
For the past two years, I have conducted a pilot study on whether or not a half-dose distemper and parvovirus vaccine elicited enough immunity to these viruses in adult dogs weighing less than 12 pounds. I thank the
American Holistic Veterinary Medical Foundation for supporting this study and am pleased to share the results with you. The full study results are published in the
Journal of American Holistic Veterinary Medical Association and
Animal Wellness. The Basic Foundation: What you need to know What is Parvovirus?
The canine parvovirus (CPV) infection is a highly contagious, ubiquitous viral illness that affects dogs, and the parallel ubiquitous feline parvovirus (named feline panleukopenia virus, FPV) affects cats. These viruses manifest in different forms. The more common form is the intestinal form, which is characterized by vomiting, diarrhea, weight loss, and lack of appetite (anorexia). The less common form is the cardiac form, which attacks the heart muscles of very young puppies, often leading to death. The majority of cases are seen in puppies that are between six weeks and six months old. –
PetMd.com
In kittens infected
in utero from their asymptomatic or mildly ill dams, cerebellar hypoplasia, stillbirths and neonatal death occur. For those that survive, the small cerebellum leaves them ataxic and uncoordinated.
What is Distemper?
Canine distemper (CDV) is a contagious and serious viral illness, usually with no known true cure. The virus, which is spread through the air and by direct or indirect (i.e. utensils, bedding) contact with an infected animal, initially attacks a dog’s tonsils and lymph nodes and replicates itself there for about one week. It then attacks the respiratory, urogenital, gastrointestinal, and nervous systems. In the initial stages of distemper, the major symptoms include high fever, reddened eyes, and a watery discharge from the nose and eyes. An infected dog will become lethargic and tired, and will usually become anorexic. Persistent coughing, vomiting, and diarrhea may also occur. In the later stages of the disease, the virus starts attacking the other systems of the dog’s body, particularly the nervous system. The brain and spinal cord are affected and the dog may start having fits, seizures, paralysis, and attacks of hysteria. –
PetMd.com
What is a titer test?
A titer test is a simple blood serum test that measures the presence of antibodies to vaccine or naturally exposed viruses or other infectious agents.
Immunizing against parvovirus and distemper.
According to the American Animal Hospital Association’s (AAHA) 2011 vaccination guidelines, distemper and parvovirus vaccines are part of the necessary “core” vaccines that every dog should have along with adenovirus-2 (protects against infectious canine hepatitis and part of the kennel cough complex) and rabies.
In the United States, rabies is governed by state and municipal laws. I will be
disregarding the rabies topic in this article as clinical trials to change rabies laws are currently underway and rabies titers are performed at Kansas State University. I do not condone or recommend giving half-doses of the rabies vaccine as the law currently states the whole vial must be administered – regardless of size of dog – for the dog to be considered vaccinated. The same applies to cats where rabies vaccine is mandated.
Regarding distemper, adenovirus-2, and parvovirus vaccines, AAHA recommends vaccinating puppies every three to four weeks between the ages of 6 and 16 weeks. The final dose should be administered at 14 to 16 weeks of age to reduce maternal antibody interference. Additionally, the association suggests vaccinating again at one year of age against these diseases, then every three years moving forward.
I applaud the AAHA guidelines committee for changing its recommendation of annual distemper, parvovirus and adenovirus vaccinations to every three years. This is a big leap forward! However, I respectfully disagree with part of this protocol:
Most importantly, it has been found through titer testing that the initial puppy vaccinations generally provide lifelong (
NOT lifetime) immunity in the majority of dogs. By the time a dog may have reduced antibody levels that warrant revaccination, he is generally 10 years of age or older and the vaccination can be more risky and elicit adverse events at that age. The senior dog is also more than likely not in situations that would necessitate it.
I do not recommend the adenovirus-2 vaccine for hepatitis because until just recently in some dogs from one litter, there have been no documented clinical cases of infectious canine hepatitis in North America for at least 15 years. If an outbreak occurs regionally, then I will likely change my mind based on the situation and only for the affected region. Further, a published study showed that combining adenovirus with CDV in modified live vaccines (MLV) vaccines causes cell-mediated immune suppression for up to 10 days afterwards at an age when young pups are going through the changes of new homes, diets, and environment.
I generally do not recommend vaccinating puppies against these clinically important infectious diseases before the age of 9 weeks due to the partial neutralizing effect of residual maternal antibodies that are provided in the colostrum of mother’s milk. The exception would be an endemic local parvovirus outbreak where giving a single monovalent CPV vaccine may be needed as early as 5-6 weeks of age.
If the first distemper and parvovirus vaccine is properly timed between the 9-10 weeks of age mark, a second vaccine given at the age of 14-16 weeks should immunize them effectively.
The type of vaccine administered.
Distemper, parvovirus and adenovirus are MLV. As the name suggests, MLV vaccines use a modified, but weakened, form of the live microorganism(s). 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 these 3 viruses and FPV of cats, true immunization prevents further infection, a process known as “sterile immunity”.
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. When MLV vaccines are given to pets with compromised immune systems, the animal is actually at some risk of contracting a weakened form of the virus from the vaccine.