Is it Possible to Over-Vaccinate Dogs?

Owners are increasingly concerned about over-vaccinating their dogs. As a responsible pet owner, it’s natural to question what’s best for your dog’s health. Recent research indicates that vaccinating dogs every year is unnecessary and could potentially harm our pets.

Studies now show that vaccinating adult dogs every three years is sufficient. However, some veterinary practices still recommend annual vaccinations.

It may be possible to over-vaccinate dogs. The American Animal Hospital Association (AAHA) recommends that vets vaccinate adult dogs every three years. This is in contrast to older guidelines, which state that pets should receive vaccinations annually. Despite this new information, some veterinary practices continue to vaccinate dogs annually.

Dog over-vaccination has been controversial in the veterinary industry for many years. As far back as 1995, studies were held to investigate the effects of revaccination. The article, titled “Are we vaccinating too much?” highlighted concerns about the lack of scientific documentation to back up label claims that call for annual revaccination. This article was the catalyst for changing outdated revaccination protocols.

All dog vaccines were originally licensed by the USDA. The vaccines were marketed based on short-term studies. These studies were complete only a few weeks or months after the initial vaccination. Due to this, all vaccines included the disclaimer “annual revaccination recommended” without in-depth knowledge of whether the duration of immunity (DOI) was one year or a lifetime. Now, veterinarians have more insight into the DOI of vaccines.

Risks of Over-Vaccinating Dogs

The main risk associated with over-vaccinating dogs is exposure to adverse side effects. With each dose, a dog is at risk of contracting side effects, so it’s best to only vaccinate your dog as necessary to reduce the risks.

Some studies suggest that the risk of adverse reaction significantly increases as the number of doses increases. In addition, the risk for dogs weighing less than 5kg is at 4 times more risk than dogs weighing over 45kg. This claim backs up other studies. The risk of adverse reaction is inversely related to the dog’s weight. This means that smaller breeds have significantly more adverse reactions than others. Young, small breed dogs who receive multiple vaccines per vet visit are at greatest risk of side effects, particularly within 72 hours of vaccination.

But what are the adverse reactions? In the worst-case scenario, a routine vaccination could incite any of these reactions: a lump or swelling at the vaccination site, facial swelling, generalized urticaria, fever, vomiting, diarrhea, anaphylaxis, shock or collapse. The most common adverse reactions are pain, soreness, and stiffness at the injection site. Fortunately, severe adverse effects are rare.

Core Vaccines

Core vaccines protect our pets against life-threatening diseases with a global distribution. The diseases have a significant mortality rate without vaccines. In general, vaccination results in good protection from these diseases. According to the AAHA, the core vaccines are necessary for every puppy between 8 – 16 weeks of age.

The four core vaccines are for canine distemper, canine parvovirus, canine adenovirus, and canine parainfluenza. These vaccines make up the DHPP vaccine. For initial puppy vaccination (<16 weeks of age), one DHPP dose is recommended every 3-4 weeks, with a final booster given at around 16 weeks of age. After this, the vaccine is only necessary every 3 years.

The rabies vaccine is another core vaccine. Rabies vaccines are the only vaccines that must be given by law. Some states of the USA require rabies vaccinations more frequently than every three years due to its prevalence.

Non-Core Vaccines for Dogs

Non-core vaccines for dogs are optional or only necessary in specific circumstances. A vet will use a non-core vaccine depending on the exposure risk of the dog. The risk is based on the dog’s lifestyle and geographic distribution of the disease. In addition, several of the diseases involved in non-core vaccines are self-limiting or respond well to treatment.

Vaccines considered to be non-core include the canine influenza virus (H3N8), canine distemper-measles combination and Bordetella bronchiseptica, and Borrelia burgodorferi. These vaccinations are generally less effective than core vaccines. Canine parainfluenza is not always considered a core vaccine. Regardless, it is included in most combination vaccines like DHPP.

A prominent example of a non-core vaccine is the canine influenza virus vaccine. Canine influenza virus (H3N8) emerged in the USA in 2003. The virus is enzootic in Florida, Colorado, New Jersey, New York, and Pennsylvania. Another strain, H3N2, emerged in 2015 in Illinois and spread to several other states. Vaccinations are commercially available for both of these strains. A combination of H3N8 and H3N2 is also available. This non-core vaccine may be necessary for some dogs who are in close contact with others on a regular basis, such as those who board in kennels. While these vaccines do not prevent the disease entirely, they may reduce clinical signs and shedding of the virus.

Titer Test

The titer test is a laboratory test that measures the level of antibodies in the blood. Antibodies are produced by plasma cells. The immune system uses antibodies to neutralize pathogens. The antibody works by recognizing antigens. An antigen is a unique molecule belonging to a pathogen. Using a binding mechanism, an antibody tags a pathogen for attack by other parts of the immune system. This immune response can come from vaccination or natural exposure. For those who worry about over-vaccinating their dogs, a titer test can help. It provides evidence as to whether your pet still has antibodies against a specific disease from previous vaccination.

Advantages of the titer test

American Animal Hospital Association (AAHA) vaccine guidelines say that a titer test in pets is an appropriate way to check for immunity to parvovirus, distemper, and adenovirus. However, it is not recommended for canine leptospirosis, bordetella, or Lyme disease because these vaccines only provide short-term protection. 

Rabies vaccines do provide long-term protection, and the titer tests for rabies are also considered to be a very accurate measure of immunity. However, vaccination against rabies is mandated by law, and unfortunately no state in the U.S. accepts titer test results in lieu of vaccination history. So, if your dog bites someone, they will still need to be quarantined, even if a titer test shows they have immunity. 

How long does a titer test last? 

Most veterinarians recommend repeating a titer test for a specific illness every one to three years, although many vaccinations protect dogs from illness for three years or longer. Some studies have even shown that a majority of dogs (over 90 percent) have enough antibodies from a vaccination to protect them for seven to nine years. If you can’t titer test for some of your yearly dog vaccinations for any reason, don’t hesitate to take your pup in for their boosters.

Costs

The cost of a titer test for dogs varies depending on the location and the type of test. The average cost of a titer test ranges from $40 to $60.  

NJ and Titer

Currently NJ does not accept Titer test in leu of a rabies vaccination unless there is a medical reason.  If your vet believes your pet should not receive a rabies vaccination, your veterinarian must fill out a form annually.