Side Effects of Vaccine on Dogs (By Vaccine): Our Vets Explain

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German Shepherd Getting a Vaccine

This article was updated on September 5th, 2023

We all want to keep out canine companions healthy and happy. One of the best and easiest ways to do this is by getting them vaccinated. Vaccines help protect our pups against many contagious and fatal diseases with just one small stick of a needle. However, vaccines aren’t all reward with no risk. Vaccines do have some side effects, though often mild and very rarely serious. Here is what to expect from vaccinating your dog.

Why we should vaccinate our dogs

Vaccinating your dog is in your dog’s best interest to protect them from serious and potentially deadly diseases. Like humans, dogs are susceptible to a variety of infectious diseases that can spread quickly and cause serious health problems. Vaccines can help prevent sickness from these diseases, or at least reduce the severity of the illness.

The most common and dangerous diseases that dogs can be vaccinated against include rabies, distemper, parvovirus, and hepatitis. These diseases are dangerous and expensive to treat, but they’re preventable with common vaccines. Vaccinating your dog is also important for public health. Rabies, especially, is a human health concern and every animal in a home should be vaccinated.

What are common side effects of vaccines on dogs?

Like with any medical procedure, vaccinations can potentially cause side effects in dogs. However, it’s important to note that the vast majority of dogs have no or only mild adverse reactions to vaccines. Very few have even moderate to severe issues, we’re talking even less than 1% here. Most of the side effects of vaccines last only a short time, and the benefits of vaccination far outweigh the risks. Here are some of the most common side effects:

  • Mild lethargy (common)
  • Mild fever (common)
  • Localized swelling or soreness (common)
  • Decreased appetite (common)
  • Runny nose or sneezing following an intranasal vaccine
  • Allergic reactions (uncommon)
  • Anaphylaxis: a severe, life-threatening allergic reaction (rare)

How severe these side effects are on dogs

Most vaccine side effects are mild, short-lived, and not of major concern. Other more serious reactions, while rare, are possible and should be taken into account. Here is more information by side effect:

1) Mild lethargy: This can be a normal response and is usually mild and resolves on its own within 24 hours. Severe lethargy is unlikely but should be reported to your veterinarian immediately.

2) Mild fever: Some dogs will develop a mild fever (about 102.5° to 104.0° F) after being vaccinated. Mild fever may resolve on its own within 24 hours. Contact your veterinarian if a fever is noted for advice on how to manage it.

3) Localized swelling or soreness: Sometimes, owners note swelling or soreness at the site of the injection (read our article about vaccine lumps). This is usually mild and goes away on its own within a few days; a cold compress gently held against the site can help relieve discomfort.

4) Allergic reactions: While rare, some dogs may have an allergic reaction to a vaccine. Again, this is rare, only happening in less than 1% of dogs vaccinated. Symptoms of an can include swelling of the face or legs, difficulty breathing, hives, or vomiting. If you notice any of these symptoms in your dog after a vaccination, you should contact your veterinarian immediately as an allergic reaction is concerning and needs treatment.

5) Anaphylaxis: This is one of the rarer vaccine side effects. Anaphylaxis is a severe, life-threatening allergic reaction. It is extremely rare but can cause difficulty breathing, collapse, and shock. If you suspect your dog is experiencing anaphylaxis after a vaccination, seek emergency veterinary care immediately.

It’s important to note that the vast majority of dogs do not experience any adverse reactions to vaccines.

In most cases, any side effects that do occur are mild and short-lived. If you have any concerns about dog vaccines or side effects, be sure to contact your veterinarian.

Most common vaccines

When it comes to deciding which vaccines to give your dog, your veterinarian will have the best advice. There is a group of vaccines called the core vaccines that every dog regardless of lifestyle should have. Those include:

  1. Distemper
  2. Parvovirus
  3. Adenovirus (hepatitis)
  4. Rabies

There are other vaccines though, that may be recommended depending on a variety of factors, including your dog’s age, lifestyle, and geographic location.

  1. Bordetella vaccine: Commonly known as kennel cough, this vaccine is recommended for dogs that are frequently around other dogs. For instance, dogs who are frequently at dog parks, daycare, boarding kennels, or groomers.
  2. Leptospirosis vaccine: This vaccine is recommended for dogs that spend time outdoors, particularly in areas with standing water. This can include backyards, parks, or woodland areas.
  3. Lyme disease vaccine: This vaccine protects your dog from Lyme disease, which can cause a variety of symptoms, including fever, lameness, joint pain, and sometimes even severe kidney disease. It’s recommended for dogs that live in areas with high tick populations.
  4. Parainfluenza: This virus causes respiratory symptoms including coughing, a runny nose and fever. It’s often part of the Kennel cough vaccine as it is easily passed from dog to dog in close confines.

Your veterinarian will be able to assess your dog’s individual needs and recommend a vaccination schedule that is appropriate for them. If your dog has ever had a history of vaccine side effects, this will help guide the veterinarian’s decision.

Common side effects by vaccine

  • Distemper: soreness at infection site, low grade fever, lethargy
  • Parvovirus: soreness or itchiness at injection site, mild fever, lethargy
  • Adenovirus vaccines: lethargy, decreased appetite, upset stomach
  • Bordetella vaccine: runny nose and sneezing if given intranasally
  • Leptospirosis vaccine: lethargy, swelling at injection site, rarely vomiting and diarrhea
  • Lyme disease vaccine: lethargy, swelling at injection site, decreased appetite, mild fever

When to visit the vet – If you notice side effects

If you suspect that your dog is experiencing side effects from a vaccine, it’s important to contact your veterinarian right away for guidance on how to proceed. They will be able to assess your dog’s symptoms and provide recommendations on whether you should bring your dog in for an evaluation.

In general, you should contact your veterinarian immediately if your dog experiences any of the following symptoms after a vaccine:

Disclaimer: This content is not a substitute for veterinary care. Always consult with your vet for health decisions. Learn more.

  1. Difficulty breathing or swelling of the face, lips, or tongue
  2. Seizures or collapse
  3. Extreme lethargy or weakness
  4. Persistent vomiting or diarrhea
  5. High fever or fever that lasts longer than 24-48 hours
  6. Hives or other signs of an allergic reaction

If your dog experiences mild symptoms like soreness or lethargy after a vaccine, these are usually normal and will go away on their own within a few days. However, if you have any concerns or questions about your dog’s health, it’s always best to contact your veterinarian for guidance. They will help you determine if your dog needs to be seen for evaluation or if you can monitor their symptoms at home.

Vaccine Side Effects – Your visit at the vet 

When you take your dog to the vet for vaccine side effects, you can expect a few things:

  • First they’ll ask questions about your pet – when did you first notice something was wrong? What are the things you see that are concerning?
  • Second, they’ll check some basic vital signs like heart rate, respiratory rate, and temperature
  • After these first basic steps, the veterinarian will perform an exam to check for anything abnormal

Depending on the severity of your dog’s signs, your veterinarian may recommend various treatments.

For mild symptoms like soreness, lethargy, mild fever, or mild swelling, they may recommend rest, monitoring your dog’s temperature, and potentially administering medication to keep your pet comfortable until the signs pass.
For more severe symptoms, such as allergic reactions or anaphylaxis, they may additionally recommend IV fluids to prevent dehydration, or other supportive care.

The cost for treatment can vary, as treatment for mild symptoms may be relatively inexpensive, while extensive hospitalization will carry greater cost. If the side effects noted are due to administration of a vaccine, talk to your veterinarian about the cost and what options you may have.

Frequently Asked Questions

How long can these side effects last on my dog?

The duration of vaccine side effects in dogs can vary depending on the individual dog and the severity of the side effects. In general, most side effects are mild and short-lived, typically lasting only a few days.

Is there an alternative to vaccination for my dog in extreme scenarios?

Dogs who do not have a history of vaccine side effects should still receive routine vaccinations per your veterinarian’s instructions.

However, if your dog has experienced significant side effects from vaccines in the past, your veterinarian may be able to recommend alternative vaccine schedules or alternative vaccine products.
In some extreme cases, dogs who have had vaccine side effects may not be able to receive that vaccine again. Blood titers can assist in checking their immunity level. Your veterinarian may also recommend lifestyle modifications to mitigate risk for exposure to vaccine-preventable diseases.

Are there any long-lasting side effects for vaccines given to my dog?

Long-lasting side effects of vaccines are exceedingly rare, so these situations shouldn’t be used as a baseline for deciding on a vaccine protocol in otherwise healthy, not-at-risk animals.

One potential lasting side effect is the development of injection site sarcomas. This is type of cancer that can occur at the site of an injection. It is important to note that this can happen at any injection site and is not limited to the site where a vaccine was given. This is a rare side effect, only happening in less than one in every 10,000 dogs. But it can be serious and requires prompt veterinary attention. The benefits of vaccination in preventing serious and life-threatening diseases far outpace the likelihood of developing injection site sarcomas.

Another potential lasting side effect is immune-mediated disease. This occurs when the immune system mistakenly attacks the body’s own tissues. This is also an incredibly rare side effect, but it can be serious and may require lifelong management.

It’s important to remember that the vast majority of dogs do not experience any long-lasting side effects from vaccines. The benefits of vaccination in preventing serious diseases far outweigh the risks.


  • Dr Chyrle Bonk, Veterinarian

    Dr. Chyrle Bonk received her Master in Animal Science from the University of Idaho and her Doctorate of Veterinary Medicine (DVM) from Oregon State University in 2010. She has over 10 years of experience in small animal veterinary practice, working for a veterinary clinic in Idaho.

  • Kate Howard, Vet Tech

    Kate Howard lives in Upstate New York, and received her degree in Veterinary Technology from Alfred State College of Technology in 2010. She has been a veterinary technician for 13+ years, and spent her career working primarily in general practice and veterinary emergency care. Kate has 3 dogs, a cat, and keeps a small flock of backyard poultry.

Disclaimer: This website's content is not a substitute for veterinary care. Always consult with your veterinarian for healthcare decisions. Read More.

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