Vaccine reactions in dogs are thankfully rare, but it is important for dog owners to be aware of the symptoms just in case their dog does have a reaction. Vaccine reactions can occur with any vaccine but are most commonly seen during puppy vaccine series. Symptoms of a vaccine reaction can vary from mild (pain or swelling at the injection site) to severe (facial swelling, hives, and vomiting). In this blog post, we'll discuss the symptoms of a vaccine reaction in dogs, and what you should do if you think your dog has had a reaction.
What are vaccine reactions in dogs?
There are different types of vaccine reactions in dogs and depend on the type of immune response. These include non-allergic vaccine reactions, hypersensitivity, and anaphylaxis reactions.
Non-allergic vaccine reactions: These vaccine reactions are caused by the vaccine and injection itself and not by the dog's immune system. They are more common with certain types of vaccines, such as live virus vaccines. Non-allergic vaccine reactions in dogs can occur at any age.
Hypersensitivity reactions: These vaccine reactions are caused by the dog's immune system and are more severe than non-allergic vaccine reactions. They are more common with certain types of vaccines, such as those containing adjuvants. Hypersensitivity reactions can also be caused by vaccine components, such as preservatives. Hypersensitivity reactions typically occur in puppies after the second or third booster.
Anaphylaxis vaccine reactions: These vaccine reactions are the most severe and can be life-threatening. Anaphylaxis vaccine reactions occur when the dog's immune system overreacts to the vaccine. They are more common with certain types of vaccines, such as those containing adjuvants or preservatives. Anaphylaxis vaccine reactions typically occur in puppies after the second or third booster.
Symptoms of vaccine reactions in dogs
The symptoms of vaccine reactions in dogs will vary depending on the type of reaction.
Non-allergic vaccine reactions: This is the mildest form of a vaccine reaction and symptoms often include pain or swelling at the injection site, transient fever, and lethargy. The pain experienced following vaccination is unrelated to the viral antigen but is caused by the injection itself. Injection sites can become inflamed for up to a week following the vaccination.
Hypersensitivity vaccine reactions: This is a more severe vaccine reaction and symptoms include facial swelling, hives, vomiting, and lethargy. Symptoms can develop after the vaccine in as little as a few minutes, but it can take up to 48 hours for symptoms to appear.
Anaphylactic vaccine reactions: This rare severe type of vaccine reaction in dogs usually occurs within minutes of the vaccination. Clinical signs include collapse, pallor, and in some cases difficulty breathing. Fortunately, as this reaction often occurs at the animal hospital, quick therapy can be implemented.
Treatment for vaccine reactions in dogs
The treatment for vaccine reactions in dogs will depend on the severity of the reaction. Treatment is frequently reserved for hypersensitivity responses, although it can be used at any time that clinical symptoms are present.
Mild vaccine reactions: No treatment is necessary for mild vaccine reactions and symptoms will resolve on their own. This is usually mild discomfort around the injection site. Benadryl® dosed at 2mg/kg of body weight can be safely administered and may help.
Moderate to severe vaccine reactions (hypersensitivity reactions): If your dog has a moderate to severe vaccine reaction with facial swelling, hives, and/or vomiting, they will need to be seen by a veterinarian as soon as possible. Treatment for hypersensitivity reactions usually includes antihistamines and/or steroids. Medications are typically used for 2-3 days to prevent and treat late-phase reactions.
How can vaccine reactions in dogs be prevented?
If a dog has had a vaccine reaction before, pre-treatment with antihistamines and corticosteroids can reduce the likelihood it'll have another. These medications can be administered by your veterinarian at the beginning of the vaccine appointment or orally 1-2 hours prior to vaccination. The only true prevention however is to not vaccinate them at all.
The more vaccines administered at the same time, the more likely an adverse reaction is to occur. If you have a high-risk dog or one that has had a previous minor vaccine adverse reaction, having your veterinarian separate the injections by 2 weeks may be helpful.
Are there particular or specific vaccines that increase the risk of vaccine reactions in dogs?
There is some evidence that rabies vaccines, killed vaccines such as leptospirosis, and adjuvanted vaccines are more likely to cause adverse reactions than modified live vaccines. Talk to your veterinarian and inquire as to what types of vaccines they use in their animal hospital.
What breeds are susceptible to a vaccine reaction?
One study found that Dachshunds, Pugs, Boston Terriers, Miniature Pinschers, and Chihuahuas were more likely to experience reactions to vaccines than other breeds, and is likely due to a genetic predisposition. There is some evidence that modified-live distemper vaccines may be linked with hypertrophic osteodystrophy (HOD) in Weimaraners. HOD is a developmental disease that affects the growth plates in growing dogs. However, there are conflicting studies on this issue, so it's not clear whether vaccination plays a role in Weimaraner HOD.
Frequently asked questions
If my dog has had a vaccine reaction previously, can my veterinarian only give half the dose next time?
A smaller dose of a vaccine will not prevent or reduce the risk of a hypersensitivity reaction. With vaccines such as rabies vaccines, administering a smaller dose could be illegal in some areas, as it could leave the patient unprotected.
In these circumstances, your veterinarian will recommend spacing the vaccine vaccines out over a longer period of time or, in some cases, forego vaccination altogether.
What are the side effects of the distemper vaccine in dogs?
The distemper vaccine is very well tolerated by puppies and adult dogs. In most cases, there are no side effects with the distemper vaccine. There are some risks, as with all immunizations, that a reaction may occur.
Why is my dog itchy after vaccination?
This could be either pure coincidence or signs of a hypersensitivity vaccine reaction. If your dog's itching persists for longer than 2-3 days, you should visit your veterinarian.
Why is my dog shaking after vaccination?
If shaking is the only symptom present, it could be due to a mild vaccine reaction. Mild fever and discomfort from the vaccination could result in shaking and will be self-limiting in most cases.
Vaccine reactions in dogs are fortunately not common but can range from mild to severe. If your dog has had a vaccine reaction, talk to your veterinarian about the best way to proceed with future vaccinations. Vaccinating your dog is important for their health, but their safety is also paramount. Work with your veterinarian to ensure that your dog is getting the best possible care.