Can Dog Vaccines Make a Dog Sick?

Dr. Joe Alcorn, M.S., D.V.M.

Dr. Joe Alcorn is founder of Care Animal Hospital in Temecula, California. He has a Bachelor of Science in Biology and Doctor of Veterinary Medicine from Colorado State University. He is a member of the American Veterinary Medical Association and his advice has been featured in large publications like Bustle and Martha Stewart.

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Can dog vaccines make a dog sick? It is a fair question – no pet owner wants to harm their furry family member unintentionally. With misinformation swirling online, it is hard to know fact from fiction.

As someone who has administered thousands of vaccines, we want to tell you the real truth about their risks and assuage fears around their safety. Here, I will share the science-based facts on modern vaccines, potential side effects, and what I as a vet do to minimize risks.

Can Dog Vaccines Make a Dog Sick?

Vaccine risks are extremely low. Reactions like fever and lethargy are mild and brief. Lasting harm is extraordinarily rare. Unvaccinated dogs face a more significant threat of illness, even death, from infectious diseases that vaccines prevent.

Brown dog lying on the floor

Though no treatment is risk-free, vaccines’ protection outweighs the negligible chance of side effects. Stay informed, voice concerns, yet vaccinate your pup for their best health.

Are Dog Vaccines Safe?

Vaccines are a crucial aspect of preventive healthcare for dogs. They undergo rigorous research, development, and regulatory processes before being available for veterinary use. This comprehensive testing process involves laboratory studies, controlled clinical trials, and rigorous analysis of its performance.

They are designed to stimulate an immune response in dogs without causing harm. Adverse reactions to vaccines are rare; when they occur, they are mild and temporary. These reactions may include local soreness at the injection site, a slight fever, or temporary lethargy. The most common vaccines for dogs include:

  • Non-Core vaccines: These are recommended based on a dog’s lifestyle, geographic location, and individual risk factors.
    • Bordetella Vaccine: Guards against kennel cough
    • Canine influenza: Protects against canine influenza viruses
    • Leptospirosis: Prevents leptospirosis
    • Lyme disease: Recommended for dogs in regions where it is prevalent

It is essential to understand that the benefits of vaccination outweigh the minimal risk of side effects. Vaccines prevent serious and life-threatening diseases such as rabies, distemper, parvovirus, and kennel cough. 

Bulldog puppy wrapped in brown blanket

What Are the Facts About Side Effects?

There are misconceptions surrounding the side effects of dog vaccines. Contrary to popular belief, severe side effects from dog vaccines are extremely rare. Most dogs experience only mild and temporary reactions, if any at all. 

After dog immunizations, the following probable minor and uncommon adverse effects may occur:

  • Mild sluggishness or reduced activity levels
  • Soreness or pain at the injection location
  • Temporary appetite suppression or minor stomach distress
  • Fever of low severity
  • Transient swelling or bump at the injection location
  • Sneezing or a small amount of nasal discharge
  • Light coughing
  • Changes in behavior or emotion that are just temporary

Monitoring dogs after vaccination is crucial. Observing your dog for any unusual behaviors or symptoms following vaccination is recommended, and promptly reporting them to our veterinarians. 

Responsible pet owners are crucial in recognizing and addressing potential side effects. In the rare instances of more severe side effects, our veterinary professionals, at Care Animal Hospital, are well-equipped to handle them. They are trained to identify and manage adverse reactions to vaccines. 

What Are the Best Practices for Safe Vaccinations?

Proper administration of vaccines is crucial for their effectiveness and safety. They should always be administered by trained veterinary professionals knowledgeable about the correct techniques and protocols. This helps reduce the risk of complications and ensures they are delivered most appropriately.

Maintaining a comprehensive vaccination record is essential. Keep track of the dates when your dog received them, the types administered, and any observed reactions or side effects. This record serves as a valuable reference and assists our veterinarians in tailoring future vaccination plans based on your dog’s needs and medical history.

Regular check-ups and open communication with our veterinarians are key to ensuring your dog’s optimal health. During these visits, our veterinarians can assess your dog’s vaccination needs based on age, lifestyle, and geographical location.

Woman cradling a sleeping white and black bulldog puppy to sleep

Is Concern About Vaccine Ingredients and Allergies Justified?

Vaccine ingredients are carefully selected to ensure safety and efficacy. They include antigens, adjuvants, preservatives, and stabilizers. These ingredients undergo extensive testing to confirm their suitability for use. It is important to note that the quantities of these ingredients are very low and unlikely to cause allergic reactions.

While they can occur, they are mild and easily managed. Our veterinary professionals are trained to identify and address any adverse reactions that may arise. It is crucial to inform us about any known allergies or previous vaccine reactions your dog may have experienced. 

We, at Care Animal Hospital, consider factors such as a dog’s medical history, breed, and potential allergies to ensure a safe vaccination experience. Open communication with our veterinarians is critical. Discuss any concerns about their ingredients to alleviate any worries and ensure the best possible care for your dog.

Related Questions

What Breeds Are Prone to Vaccine Reactions?

While vaccination reactions can occur in any breed, Chihuahuas, Shih Tzus, Weimaraners, Boxers, and certain Retrievers have been documented to have a somewhat greater prevalence. However, reactions can still be rare within these breeds. It is essential to consult with our veterinarians, at Care Animal Hospital, to assess your dog’s specific risk factors.

What Is the Most Common Vaccine Reaction in Dogs?

The most common vaccine reaction in dogs is mild and transient soreness at the injection site. This localized reaction may cause temporary swelling, redness, or tenderness. It resolves on its own within a few days without any intervention. 

Can Vaccines Cause Autoimmune Diseases in Dogs?

Extensive research and studies have been conducted to evaluate the safety of vaccines, and they have not been linked to the development of autoimmune conditions. The benefits of vaccination in preventing severe diseases outweigh the minimal risk of adverse reactions, and the overall incidence of vaccine-related autoimmune diseases in dogs is extremely low.


Dog vaccines undergo thorough testing to ensure their safety and effectiveness. Their ingredients are carefully chosen and used in minimal quantities, making severe allergic reactions extremely rare. By working closely with veterinarians and discussing concerns about vaccine ingredients and allergies, pet owners can ensure the well-being of their dogs.