Raise your hand if each year, when the reminder on your calendar pops up, you diligently schedule an appointment to take your pet to the vet for his annual vaccinations. Many pet owners believe they're doing the best thing for their pet by making those appointments. However, the truth is dogs and cats don't need annual vaccinations, and the trip could be doing more harm than good.

The problem with over-vaccination

With new medical insights available about the duration of immunity provided by vaccines, most veterinarians have updated their recommendation from the traditional once-a-year schedule to once every three years, or even less frequently depending on the individual animal. Ronald D. Schultz of the University of Wisconsin-Madison — one of the most respected experts on animal vaccinations — was a leading researcher behind this change. He proved over a decade ago that many vaccinations last beyond seven years and can even last the lifetime of the pet.

So, in the best-case scenario, pet owners still continuing the annual vaccination schedule are incurring an unnecessary expense.

In the worst-case scenario, annual vaccinations could be exposing your pet to potential side effects and chronic health problems. Serious adverse reactions to vaccinations include persistent vomiting or diarrhea, skin rash, swelling around the face, severe coughing, difficulty breathing, collapse and autoimmune disease.

Among cats, the reaction to rabies or feline leukemia vaccinations can sometimes, though rarely, include sarcomas. "Reports of a sarcoma (a cancerous mass arising from bone, cartilage, fat or muscle) developing at the site of vaccine injection sites in some animals have led to the suspicion of a link between the vaccine and a disposition in some animals to this type of reaction," reports PetMD.

Vaccinating your pet is a necessary and responsible step in pet ownership, but it should happen at the right frequency for your pet. How do you know what that frequency is? Well, there's at least one tool that can help you decide. It's called a titer test.

What is a titer test?

kitten being held by vetYour veterinarian can do tests to determine your pet's resistance to disease. (Photo: Lubava/Shutterstock)

This is a solution to preventing over-vaccination while still monitoring your pet's resistance levels.

"A titer test (pronounced TIGHT er) is a laboratory test measuring the existence and level of antibodies to disease in blood. Antibodies are produced when an antigen (like a virus or bacteria) provokes a response from the immune system. This response can come from natural exposure or from vaccination," explains Jan Rasmusen in Dogs Naturally Magazine.

Titer tests look for antibodies for parvovirus and distemper. Titers can also look for rabies, but it would be a waste of money to test for it because rabies is a vaccination required by law to be administered periodically anyway. Titer tests show whether or not your pet has the antibodies for a certain disease. However, this isn't the same as testing your pet's immunity level.

Our bodies may stop making antibodies for a disease when that disease hasn't been present for awhile. But when the disease does pop up again, our immune system remembers that disease and often can start churning out the antibodies. A titer test only shows how many antibodies are present for a particular disease, not if your pet's immune system can function against that disease.

So, even if a titer test shows your pet has a low number of antibodies, or even no antibodies,that doesn't necessarily mean your pet is unprotected. But it does raise an important question about whether or not to re-vaccinate. Pet owners have to make the decision — do they want to trust that the pet's immune system is working just fine or to re-vaccinate anyway?

Schultz says owners should definitely re-vaccinate. “The risks of contracting the disease are far greater than the risk posed by vaccines — particularly in a very infrequently vaccinated animal.”

Vaccinate every 3 years or less

Shelters have enough animals waiting for homes. Indoor cats have less risk of exposure to diseases than outdoor cats, so they may be able to have fewer vaccinations compared to their outdoor peers. (Photo: Ilya Marchenko/Shutterstock)

Titer tests can help pet owners stretch out the frequency of vaccination and help sort out which vaccines should be considered, helping pet owners avoid over-vaccination while keeping a certain level of peace of mind. The AAHA recommends that adult dogs get tested every three years to check for antibodies for the most worrying diseases: parvovirus, distemper and canine hepatitis.

Nancy Kerns at Whole Dog Journal says it best: "The truth is, there is no single vaccination protocol that will protect all dogs for all things, without over-vaccinating most of them. Vaccination really ought to be determined on a case-by-case basis, because each dog’s risk factors are unique, based on his age, genetic inheritance, current health, geographic location, and lifestyle." This of course goes for cats as well.

Which vaccines your pet needs and how often he should receive them depends on a variety of factors including age, activity level, exposure to potential diseases and even genetic predisposition to particular diseases.

For instance, indoor cats have little risk of exposure to many diseases compared to outside cats, so they can be safe receiving fewer types of vaccinations less frequently than their outdoor peers. Owners of active dogs that are often out playing in dog parks with many other dogs, including unfamiliar ones, will likely need to take a more diligent look at their dog's vaccination schedule, whereas owners of senior dogs or a dog with a compromised immune system may want to go with only the bare essentials. Location is also a factor. For instance, are you in a part of the country where Lyme disease is prevalent such as on the East Coast, or is that a rarity, such as on the West Coast?

There aren't a lot of vets who will tell you that you only need to vaccinate your pet once and that's it. There are too many questions and variables for this to be the case. However, a good vet is not going to tell you that you need every type of vaccination every year.

A savvy vet will tell you that you only need to vaccinate your pet once every three years, or less frequently depending on specific factors unique to your pet, and the vet should discuss those factors with you. The vet should also discuss what vaccines are necessary, and which can be avoided.

It's important to continue to make annual visits to the vet for checkups on the overall health of your pet. However, vaccination shots do not need to be part of the visit. The next time you're at the vet, make a point of discussing your pet's vaccination needs and the best way to balance minimal vaccinations with maximum protection. Sort out what factors affect your pet, both for potential exposure to disease and also sensitivity to over-vaccination. You can then work together to come up with a plan that suits your pet's individual needs.

Jaymi Heimbuch ( @jaymiheimbuch ) focuses on wildlife conservation and animal news from her home base in San Francisco.

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