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Vaccine Reactions in Dogs

While there is a risk of potential reactions when it comes to vaccinating your dog, the benefit of lifelong protection against serious diseases far outweighs that risk. Today, our Stockton vets discuss dog vaccinations as well as potential side effects associated with vaccine reactions.

The Importance of Canine Vaccines

Most pet owners take their dogs to the vet for vaccinations and to get their annual exams. Although some dogs leave the office and never have issues or problems with the vaccinations, some dogs receive an injection and experience a variety of side effects, such as your dog being lethargic after shots. Most side effects are mild and should subside within 24 hours.

The typical dog vaccines include rabies, adenovirus, distemper, hepatitis, parvovirus, corona, and parainfluenza. For the vast majority of dogs, the benefits of appropriate vaccination far outweigh the risks. However, as is often true in medicine, dog vaccine side effects are possible.

Vaccine reactions in dogs can be stressful and scary for you as a pet parent, but they will be less so if you know what to watch for and how to react.

How & When Vaccines Are Administered

Typically, vaccines are injected into your dog using a needle. There are certain vaccinations and times when a nasal spray may be used such as the Bordetella vaccine when the dog is younger than 8 weeks old.

Possible Reactions

Mild reactions or responses to routine vaccinations are to be expected. While it may be stressful for you to witness your dog having any sort of reaction to a vaccine it's important to keep in mind that these reactions are generally very mild and quite short-lived. Knowing what to keep an eye out for in terms of vaccine reactions and what steps you should take if your dog begins to show serious signs of a reaction will go a long way toward preventing vaccine-related stress. 


The most common reaction that dogs tend to experience after vaccinations is a feeling of malaise, lethargy, or discomfort, often accompanied by a very mild fever. Many people would describe this feeling as "off." This reaction is the immune system of your dog working to respond to the vaccine appropriately. These symptoms are quite normal and should only last one or two days. If your dog isn't back to their normal levels of energy after a couple of days, contact your vet.

Lumps & Bumps

If your dog receives the injectable form of the vaccine, lumps and bumps can occur, especially around the injection site. A small, firm bump may develop, as well as some tenderness and stiffness in the area. These bumps are the result of your dog's immune system rushing in to fight irritation at the injection site. 

That said, any time the skin is punctured there is a chance of infection. Be sure to keep an eye on the site where the injection was given. Look for signs of swelling, redness, discharge, and pain. If left untreated, infected areas may lead to more serious conditions. If you notice the area becoming increasingly red or showing any of the symptoms listed above, contact your vet.

Sneezing & Nasal Congestion

This reaction can be quite common if your dog received the Bordetella vaccine as a nasal spray. This reaction encompasses several symptoms that appear much like a cold, including coughing, sneezing, and a runny nose. Most dogs recover from these symptoms within a day or two. If your dog is showing more severe symptoms or does not recover within a couple of days, it's time to call the vet.

Severe Reactions to Vaccinations

If your dog has any sort of reaction to their vaccines, the reaction should be mild and only last a short while. On rare occasions, your pet may experience a severe reaction and it is important to know what these reactions look like.

The most common of these exceedingly rare reactions is anaphylaxis. This is a severe allergic reaction that can be characterized by swelling in the face, hives, vomiting, issues breathing, diarrhea, and itchiness in your dog. This reaction typically occurs within a few minutes or hours of your dog receiving a vaccine but may take up to 48 hours to appear.

If your dog is showing any of the symptoms of anaphylaxis after receiving vaccinations, contact your emergency veterinarian as soon as possible.

Preventing a Dog's Reaction to Vaccines

Vaccines help to protect your pup's long-term health and well-being, preventing diseases from ever arising in the first place. And the risk of your canine companion having a serious adverse reaction to vaccination is quite low. 

All of that being said, if your dog has previously reacted to a vaccine always inform your vet ahead of time. They may advise you to skip a certain vaccine in the future to mitigate risks.

The risk of reactions to vaccinations increases somewhat when multiple vaccinations are given at one time. This can be particularly true in smaller dogs. To help reduce the risk of reactions, your vet may suggest splitting vaccines up to limit the risk of a reaction.

Is your dog due for their vaccinations or booster shots? Contact our Stockton vets to book an appointment.  

New Patients Welcome

New Patients Welcome

Bear Creek Veterinary Hospital is welcoming new patients! Our compassionate vets are experienced in caring for Stockton companion animals. Get in touch today to book your pet's first appointment.

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