Over-Vaccinating Dogs – When Is It Too Much, And What Are The Risks?

Over-Vaccinating Dogs – When Is It Too Much, And What Are The Risks?

Over-vaccinating dogs is a growing concern for owners. You want what’s best for your pet, so it’s natural for you to question what’s right for their health. More recent research suggests that the annual revaccination of dogs is unnecessary, and could actually expose our pets to a greater risk of adverse effects.

Instead, studies now show that vaccination every three years is more appropriate for adult dogs. Despite this new information, some veterinary practices continue to vaccinate dogs annually.

effects of revaccination
Revaccination is unnecessary and could expose our pup to greater risks.

Is it Possible to Over-Vaccinate Dogs?

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 informtion, 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 This article was the catalyst for changing outdated revaccination protocols.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.

Core Vaccines for Dogs

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, but not all countries deem it necessary. This is because rabies is not a threat in countries like the UK. In the USA, 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, so check your local laws.

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.

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.

change in a dogs resistance levels
Your pup’s resistance levels can change due to stress.

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

The most recommended titer test examines antibodies for parvovirus, distemper, and rabies. For most dogs, tests for other diseases are not necessary. In theory, the titer test helps to determine whether your dog requires additional vaccination. It’s also useful when making a decision about vaccinating a dog with an unknown vaccination history.

Disadvantages of the titer test

On the negative side, titer tests are not always accurate. There is no way to reliably predict antibody levels three or six months down the line. A dog’s resistance levels can also change due to several factors. These include stress, medication, and disease. As such, antibody levels might not be consistent over time. Furthermore, some boarding kennels won’t accept a titer test as proof of immunity. There is also no titer test for diseases like Bordetella.

Where the Law Comes In

Even if a titer test tells you that your dog doesn’t need a rabies vaccine, you will still need to get one in accordance with your local laws. No state will accept a rabies titer test as a measure of immunity in place of full vaccination. As such, it’s important to keep up to date with your pet’s rabies vaccination regardless of their titer test results. Failure to vaccinate your pet against rabies is illegal in the USA. The frequency of this vaccination varies by state so it’s vital that you check how often you must vaccinate your pet.

Over-Vaccinating Dogs – FAQs

Got any more questions about over-vaccinating dogs? Feel free to consult our Frequently Asked Questions section for more details.

At What Age Should You Stop Vaccinating Your Dog?

Your veterinarian will need to discuss this with you. Ultimately, your vet knows the complete medical history of your dog. They can decide whether it is still safe for your senior pet to receive vaccines or not. Typically, senior pets receive most vaccines every three years unless it is no longer safe to do so. Regardless of your pet’s age, they will still require a rabies vaccine in accordance with local laws unless they are exempt for other reasons.

Do Dogs Need Vaccines Every Year?

Dogs do not require annual vaccinations. Instead, the recommendation is that a dog should receive vaccines every three years. Revaccination should include the four core vaccines: canine distemper, canine parvovirus, canine adenovirus, and canine parainfluenza. DHPP is the name given to this combination of core vaccines.

For initial puppy vaccination (<16 weeks of age), one dose is recommended every 3-4 weeks, with a final booster given at around 16 weeks of age. A booster is necessary at 6 months of age to one year. After this, core vaccines are only necessary every 3 years.

Your pet’s rabies vaccination should be given according to your local laws. Some states ask that you vaccinate for rabies yearly. Others only ask that you vaccinate every three years.

What Vaccines Does my Dog Really Need?

What your dog needs as an individual might vary depending on their medical history and location. However, core vaccines are the recommendation for all dogs. This applies unless a medical condition renders them unable to receive a vaccine. The core vaccines are for canine distemper, canine parvovirus, and canine adenovirus (CAV). Canine parainfluenza is also sometimes an inclusion in core combination vaccines. Rabies vaccines are core in some countries, but in others, they are deemed unnecessary. This is because rabies is not common in some countries like the UK.

parvovirus is deadly
Puppies are more at risk of getting Parvovirus.

Is the DHPP Vaccine Necessary?

The DHPP vaccine is paramount for protecting your dog from life-threatening diseases. This vaccine protects your dog from canine distemper, infectious hepatitis, parainfluenza, and parvovirus. Protection from these illnesses is vital for your pet’s health. At the same time, some veterinarians do not consider parainfluenza to be a core vaccine because of its low mortality rate.

In order to appreciate the necessity of the DHPP vaccine, it’s important to understand what diseases it protects your pet from.

  • The D in DHPP stands for distemper. Distemper is a disease from viruses of the Paramyoviridae family. Prior to the vaccine becoming available, distemper was the leading cause of infectious disease death in dogs
  • The H in DHPP stands for infectious canine hepatitis. This is a very serious condition with a mortality rate between 10 and 30 percent. Mortality is typically highest in young dogs
  • The first P in DHPP stands for the parainfluenza virus. While this virus is not as deadly as the others, it is still highly contagious. The disease spreads rapidly in shelters and kennels. The parainfluenza vaccine is not always considered a core vaccine. Even so, it is used in the majority of combination vaccines. Inclusion of this vaccine is debatable amongst veterinarians
  • The final P in DHPP stands for parvovirus. This viral disease is deadly if not treated. While 85 to 90 percent of treated dogs survive parvovirus, untreated dogs face a mortality rate exceeding 90 percent. Puppies are the most at risk of death from parvovirus This makes it even more vital that you vaccinate your pet as early as possible

Why Shouldn't You Vaccinate Your Dog?

The only time you should not vaccinate your pet is if the vaccine would cause life-threatening adverse effects if given. It is especially important that your pet receives the necessary core vaccines. This ensures that they have protection from some fatal diseases.

In some circumstances, your dog might be exempt from the rabies vaccine. Exemption circumstances include an anaphylactic reaction soon after a rabies vaccine, immune-mediated hemolytic anemia, polyradiculoneuropathy, if your dog is currently on immunosuppressive therapy, or if your dog has a terminal prognosis. It is only in these circumstances that your dog should not receive the rabies vaccine.

In conclusion, over-vaccinating dogs may expose dogs to adverse side effects. While core vaccines are undoubtedly important, it’s also important to evaluate how often they should be given due to the risks involved. Current research suggests that annual revaccination is unnecessary. Instead, the revaccination every three years is more appropriate and safer for our pets.