Skip to Main Content
Ask About Financing

Vaccine Reactions in Dogs: Everything You Should Know

When it comes to vaccinating your dog, the benefit of lifelong protection against serious diseases far outweighs the risk of your dog possibly having a bad reaction. In today's article, our Williamsburg vets discuss vaccine reactions in dogs so owners can make informed decisions when it comes to vaccinating their dogs.

The Importance of Canine Vaccines

Most pet owners understand the importance of taking their dogs to the vet for vaccinations and routine exams. Although dogs often leave the office and never have issues or problems with the vaccinations, some dogs receive an injection and experience a variety of side effects, like if your dog is lethargic after shots. Most side effects are mild and will clear up within 24 hours.

The typical dog vaccines include rabies, adenovirus, distemper, hepatitis, parvovirus, corona, and parainfluenza. For most dogs, the benefits of being protected from these illnesses and diseases are far more important than having a small reaction to a vaccination.

Vaccine reactions in dogs can be concerning for any pet parent, so it helps to know what to watch for and what to do if your dog does react.

How & When Vaccines Are Administered

Vaccines are typically injected into your dog using a needle. However, certain vaccinations can be given using a nasal spray when a dog is under eight weeks old, such as the Bordetella vaccine. Your puppy yelping after a vaccination is nothing to worry about. They are likely just a bit frightened, and although the vaccine should be next to painless, if they feel even the slightest pinch, they may not be happy about it and let out a little whine.

Possible Dog Vaccination Side Effects

Although they don't always occur in every dog, 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 vaccination is a feeling of lethargy or mild discomfort, which may be accompanied by a very mild fever. Many people would describe this as their dog seeming slightly "off." This reaction is simply the immune system of your dog working to respond to the vaccine appropriately.

These symptoms are normal and should only last a day or two. If your dog isn't back to their normal levels of energy after a couple of days, contact your vet to have them checked out to make sure everything is fine.

Lumps & Bumps

If your dog receives an injectable form of the vaccine, lumps and bumps may appear, typically around the injection site. They may also experience some tenderness and stiffness in the area, so if your puppy is crying when you pick them up after a shot, it's likely just due to their mild discomfort. These bumps are the result of your dog's immune system rushing in to fight irritation at the injection site. 

That being said, any time the skin is punctured there is a chance of infection, so it is important to keep an eye on the injection site for a few days. Look for signs of swelling, redness, discharge, and pain. If left untreated, infected areas can lead to more serious health problems. If you notice the area becoming increasingly red or showing any of the symptoms mentioned above, contact your vet.

Sneezing & Nasal Congestion

This reaction is more common if your dog receives 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 seem to have recovered within a couple of days, it's time to call the vet.

Severe Reactions to Vaccinations

Remember, side effects from dog vaccinations should be mild and only last a short while. However, on rare occasions, your pet may experience a severe reaction and it is important to know what these reactions look like so they can be cared for right away.

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

If you notice your dog is having trouble walking after their shot, call your vet right away. This could be due to a number ofd reasons like an allergic reaction, so it is best to have your vet examine them as soon as possible.

If your dog is showing any of the symptoms of anaphylaxis after receiving vaccinations, contact an emergency veterinarian immediately.

Preventing a Dog's Reaction to Vaccines

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

That said, if your dog has previously reacted to a vaccine, be sure to notify your vet in advance. They may advise you to skip a certain vaccine to eliminate the possibility of having another reaction.

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

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Is it time for your dog to come in for their vaccinations or booster shots? Contact our Williamsburg vets to book an appointment.  

New Patients Welcome

Are you looking for a veterinarian in Williamsburg? We are accepting new patients to our veterinary family.

Contact Us

(757) 253-0656 Contact