Pet Health Community

Most of it deals with the actual law present in your area. In the U.S., rabies is still present in wild and feral animals and can be spread to humans, meaning states are very concerned about public safety. A good chunk have moved to allowing a three-year vaccine to be used as long as the first and initial booster are within a year apart. Some states are very specific about this and regulate that the vaccines must be given no later than 365 days after the first vaccine. 366 days is legally not covered according to them and you can fall under fines or penalties if he is considered unvaccinated after a year. Based on what your state or area allows, a titer may not be good enough for them unless a significant vaccine reaction has already occurred and medical professionals lean against re-vaccinating unless absolutely necessary. If your state allows the titer and it shows that your pet is not protected, you will have to vaccinate anyways.

Vaccines typically work differently than other medications like antibiotics as well so weight based doses are considered very rare. Some doctors, however, will only give a half dose for very small animals though these are typically under 5 pounds. Vaccine associated sarcomas are much more common in cats, some of which are genetically predisposed to them. A reaction to a vaccine is often waived by the veterinarian who did the procedure and usually consists of a steroid and antihistamine injection.

As always though, call your vet with your concerns and discuss it with them.

Hi An_240886,

I'm not a vet nor tech, but my "hobby" is listening to recordings of talks given at vet continuing education conferences by some of the top experts and researchers. I have a particular interest in vaccinology and have gotten to know one of the leading experts, Dr Richard Ford, at NC State Univ who is a co-author of both the official Canine and Feline Vaccination Guidelines. You are lucky that only a few weeks ago, NEW AAHA 2011 Canine Vaccination Guidelines were just published. If you want to read them, you can see them at:
https://www.aahanet.org/PublicDocuments/CanineVaccineGuidelines.pdf

The question of volume of dose for small breed dogs is one that is frequently asked, by vets as well as owners. It is based on immunology. Vaccines are not drugs which are given based on weight. Vaccines are a biological product and they need to stimulate the immune system to respond and produce protective immunity (e.g. by stimulating the production of antibodies and/or cell mediated immunity).

The analogy that Dr Ford often uses is that of bowling. If the bowling ball represents the vaccine and a strike represents the immunizing response ... the question is, what size ball is needed to be able to get that immunizing strike. If one uses a baseball size ball, will that be enough to get all the pins down? It doesn't have anything to do with the size of the dog (or cat) but rather what is needed to stimulate the immune system to produce immunity.

The fact is, the researchers don't know exactly what the minimum dose is that is needed to immunize. The companies choose a dosage amount to use in their challenge studies and all they can say is that they know that amount will produce immunity but they don't know if a lesser amount will. But it is not based on the size of the dog.

Here is one quote from the new Guidelines in its Q&A section:

"5. Should the large dog (e.g., Great Dane) be injected with the
same volume of vaccine as the small dog (e.g., Chihuahua)?

Unlike pharmaceuticals (the dose of which is usually based on
weight), a vaccine dose is not based on volume per body mass
(size), but rather on the minimum immunizing dose (inactivated
vaccine) or the minimum infectious dose (attenuated
vaccine). Therefore, the entire dose should be administered as
directed by the manufacturer. Administering less than the
prescribed dose may not induce a protective immune response"

The Guidelines also make the point that dogs that have a hypersensitivity to a vaccine may react just as strongly to a smaller amount as well, so reducing the volume may not reduce the risk of an adverse reaction and may end up not immunizing the dog.

Dr Ford (who stays current on the legal aspects of vaccinations) has said repeatedly that no states in the US will accept a Rabies titer test as proof of immunity. So save your money on titer testing. If a dog is sick (e.g. with an immune related disease) or has had a previous life-threatening vaccine reaction, some (not all) states will give the vet waiver authority ... but not based (as far as I know) on titers. If your dogs have had vaccinations before without bad reactions, there is little risk that boosters will be a problem.

You can also lessen the risk of reactions by using modified live virus vaccines for the other core vaccinations. For dogs, all Rabies vaccines are Killed Virus vaccines which tend to be more reactive. So, you can give the Rabies at a separate vet visit (minimum 2 weeks after any other vaccination). Also, avoid the Ft Dodge Rabies vaccine (now sold by Boehringer Ingelheim) which Dr Ford has said is over represented in post vaccination adverse events. Use a 3 year labeled vaccine so that you don't have to booster every year. The most reactive vaccines are the bacterial ones for Lepto, Lyme, Bordetella, etc which are non-core vaccines. If there is low risk of exposure you can avoid those.

Hope that helps.

Stephanie in Montreal