Common Reactions to Vaccines in Dogs

Vaccinations provide your pup with protection from a number of serious but preventable diseases and illnesses. While they are typically safe there is a chance that a reaction may occur. Our Wake Forest vets share the risks and benefits of vaccinations for dogs and what to do if your pup has a reaction to their vaccines.

Why is it beneficial to get my dog vaccinated?

Routinely vaccinating your dog from the time they are a puppy all the way through adulthood will help protect them from a variety of serious and preventable diseases. Diseases such as rabies, hepatitis, and parvovirus have the potential to be very serious and potentially fatal, particularly in puppies. Vaccines prevent these diseases from developing in the first place, which is always preferable to treating them once they exist in your pet.

Will my dog need every vaccine available?

Your vet will consider things like the age, breed and lifestyle of your pup before determining which vaccines are right for them. Not every dog will need every vaccination available.

What are the most commonly seen reactions to vaccines?

When it comes to modern medicine and care, there is almost always some form of risk, regardless of what is being done. While vaccine reactions in pets can be concerning, they usually do not last long and are less dangerous than the diseases that they are protecting your pup from. Knowing what the signs of a reaction are and what you should do if your dog has a reaction can help to make vaccination time less stressful for both you and your dog.  


When a dog receives a vaccine, they may experience lethargy and a mild fever. If a human were to experience this side effect then we may just say that we aren't quite feeling right. This reaction is your dog's immune system working well and responding to the vaccine appropriately. These mild symptoms are normal and should only last a day or two. If your dog isn't back to normal within a couple of days, contact your vet.

Lumps & Bumps

Another common vaccine reaction is a little bump that may form at the injection site. This bump can feel a little tender causing some discomfort for your pup. These bumps develop due to your dog's immune system rushing to resolve the localized irritation at the site. 

While these bumps are not normally a concern, they skin was broken and so you should continue to watch for the potential signs of infection. 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 & Cold Like Symptoms

Most of the vaccinations that your dog will receive will be administered through injection using a needle. However, the Bordetella Bronchiseptica and parainfluenza virus vaccines are administered by drops or sprays into the dog's nose. Reactions to these vaccines can look much like a cold and include 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.

What happens if my dog has a serious reaction to their vaccines?

Typically, any reaction that your dog experiences should not last too long and you will probably notice that your dog is back to their normal behavior within a day or two. Nonetheless, in a few rare cases, more severe reactions can occur and require immediate medical attention. Anaphylaxis is a severe allergic reaction characterized by facial swelling, vomiting, hives, itchiness, diarrhea, and breathing difficulties. Anaphylaxis typically occurs very soon after the dog receives the injection but may occur up to 48 hours after the vaccine has been administered. If your dog shows any of the symptoms listed above, call your vet immediately or contact your emergency veterinary clinic.

Is there any way to prevent vaccine reactions in dogs?

Vaccines help to protect the long-term health of your dog, and the risk of your dog having a serious reaction to a vaccine is very low. 

That said, if your dog has had a previous reaction to a vaccine, it is important to inform your veterinarian. Your vet may advise you to skip a particular vaccination in the future.

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 getting your dog's shots over the course of several days rather than all at once.

If your dog is due for routine vaccinations and you would like to learn more, please contact our Wake Forest vets today.