Vaccine Reactions in Dogs and Cats

vaccine reactions in dogs and cats boulder holistic vet angie krause

Many people are concerned about over vaccinating their pets. It can be difficult for some pet parents to have honest conversations with their veterinarian about vaccines. Many fear the label of ‘anti-vaxxer’ but also need help making an educated decision about vaccines. Some people suspect that their pet has had a vaccine reaction but don’t feel supported by their veterinarian.  In this article I am going to discuss vaccine reactions, how to identify them and how they can be prevented. I support the judicious use of vaccines and believe that pet parents should make informed decisions when vaccinating their animals.

There is an inherent risk to almost every medical treatment. Sometimes simple medical interventions go wrong. Over that past 10 years of practice I have seen a number of adverse reactions to vaccines. Thankfully, many are not life threatening. It is my belief that these reactions occur more than our profession would like to admit. Identifying vaccine reactions can be tricky in some cases. There are a spectrum of reactions. The timing of these reactions can also be variable, making correlation difficult.

I classify vaccine reactions into immediate and delayed reactions.

Immediate Reactions

These are the easiest to correlate with a vaccine because the happen within minutes to hours after the vaccine is given. These include hives, swelling of the body or face, closing of airways and vomiting/diarrhea. These can be the most life threatening and may require antihistamines and steroids.

Delayed Reactions

These happen in the days or weeks following a disease. I generally cut these off at 2 weeks post vaccination. Although I have heard other veterinarians correlating symptoms to a vaccine as late a six weeks. Delayed reactions can be vomiting, diarrhea, ear infections, itchy skin, rash, lethargy, inflammation of the spinal cord or fever. I have seen bladder inflammation, autoimmune disease and polyarthritis (inflammation of many joints).

What causes vaccine reactions?

We really don’t know why some animals have reactions and others don’t. There are so many variables including breed of dog or cat, how many vaccines are given, and the genetics of the animal.

What should I do if I suspect my pet has a vaccine reaction?

Please report it to your veterinarian. Ensure that they report this incident to the vaccine manufacturer. We need to report even suspect reactions. In many cases the vaccine manufacturer will help cover the medical bills necessary to treat the vaccine related injury.

If your pet has swelling of the central nervous system or other neurological symptoms, please don’t be afraid to treat with steroids. This can be life saving and very helpful for recovery. Seek out an integrative or holistic veterinarian that can help you use herbs and homeopathics to speed recovery.

Next, it is time to make a plan with a veterinarian you trust on how you will vaccinate in the future. If the reaction was life threatening, your veterinarian will not recommend vaccinating any further. For the rabies vaccine, it is possible to get an exemption for vaccines to show your local jurisdiction. Unfortunately many vaccine reactions only become more severe upon subsequent vaccination.

So, how do we prevent vaccine reactions?

Here is the strategy I use to minimize vaccine reactions.

  • Necessary vaccines only. There is a trend in some corporate owned hospitals to recommend every vaccine that a pet may need to live in every region of the country. This is inappropriate, in my opinion. For example, it is unnecessary to give a dog in Colorado a vaccine to prevent Lyme Disease. Discuss each vaccine with your veterinarian, and decide together which vaccines are appropriate for the lifestyle of your pet,
  • Use vaccine titers when possible. For certain vaccines, we can test blood to see if your pet has a protective level of resistance. At this time, this is not a suitable replacement for Rabies in most jurisdictions,
  • Give one vaccine at time. While this can mean a few more visits to the vet, it can help identify which vaccines are problematic for your pet. In my opinion, I see less reactions when animals are only given one vaccine at a time. This is anecdotal and there are no studies to support this opinion,
  • Only vaccinate a healthy animal. This might be the most important criteria. All vaccines are labelled for healthy animals. Not animals with ear infections, parasites, diarrhea, vomiting etc. My only exception to this rule is vaccinating puppies in and kittens in a high risk area. For example, a puppy that lives in area with a high risk of contracting parvovirus should be vaccinated. This could be a matter of life or death.

Vaccines can be confusing. It is important to educate yourself when deciding on vaccines for your pet. It is important that you can have an open and honest conversation with your veterinarian. You deserve to have a health care provider for your pet that will listen and validate your concerns.

I would love to hear from you! Has your pet had an adverse vaccine reaction?

With love,
dr. angie signature boulder holistic vet

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Claire Primo, Veterinary Nurse for BHVArianaRenee Recent comment authors
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Yes my cat Jinky has had a delayed reaction- he was throwing up and I thought it was a hairball but it wasn’t that he was getting itchy ears with a lot of wax and I had to take him to the vet and have him get antihistamine and then anti-inflammatory and then some ear cream so hoping he gets better

Does the vaccine manufactures really reimburse you for treatment due to vaccine reactions!? I have no clue who the manufacturer was-

Claire Primo, Veterinary Nurse for BHV

Hi Renee,

Yes, often the manufacturer will reimburse you for treatment or supportive care related to the vaccine reaction.

Your veterinary team can help you with filing a claim to the manufacturer, and I hope they will support you through this process!



Im so heartbroken. I brought my pomeranian to the vet for possible anal gland extraction. Since I wasnt up to date with some vaccines, (rabies was done 2 years ago and he was an indoor dog), I was told I should bring him up to date. I complied thinking I was doing the right thing. Vet extracted anal glands and said he had no issue, but took blood work and vaccinated. Within 3 weeks time, his health declined. From constipation, to lethargy, to low blood sugar, weight loss, to loss of appetite to dehydration. It took 4 trips to get… Read more »

Claire Primo, Veterinary Nurse for BHV

Hi Ariana,

I am so deeply sorry for your loss. This is so devastating and traumatic.

When vaccine reactions occur, it can be hard to know which vaccine caused them if multiple vaccines are administered at once.

Have you expressed your concerns to your pup’s veterinarian? Would they be willing to file a claim to the vaccine manufacturer on your behalf?

I am sending you such a massive hug.


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