Skip to Main Content
Ask About Financing

Vaccine Reactions in Dogs & Puppies

Vaccinations protect your dog from a variety of serious illnesses, but owners are often concerned about the possibility of vaccine-induced adverse reactions. Today, our San Diego veterinarians discuss the most common vaccination reactions in dogs, as well as what to do if your dog has a reaction to their shots.

Why Are Vaccines Reactions for dogs?

Annual vaccinations are critical in preventing your dog from contracting serious contagious diseases that can put his or her health at risk. In most cases, the advantages of having your dog vaccinated far outweigh the risk of a vaccine reaction. However, some dogs do have a reaction to receiving their shots.

Common Side Effects of Vaccinations in Dogs

It's upsetting to see your pet have an adverse reaction to vaccines. Nonetheless, loving pet owners should remember that the majority of reactions are mild, short-lived, and typically far less dangerous than the illnesses that vaccines protect against.

Vaccination time can be made less stressful for you and your pet by understanding what the most common reactions to vaccines are in dogs, and what you should do if your dog has a reaction to getting their shots.


Lethargy, mild discomfort, and a slight fever are the most common reactions to vaccines in dogs. This is often characterized by your dog just not acting like its usual self; perhaps being a little more lazy than normal. A dog being lethargic after shots is a normal reaction to vaccinations in dogs, and the symptoms should be mild and only last a day or two. A dog may also have trouble walking after their shots, which is also a normal, lethargic response. If your dog's reaction continues for more than a couple of days, contact your vet.

Lumps & Bumps

Vaccine reactions in dogs frequently result in lumps and bumps. A small, firm bump may form where the needle was injected into the skin following the vaccinations. This is a common reaction, but it's important to keep an eye on the bump to make sure it doesn't get bigger or show signs of infection like swelling, oozing, or becoming more painful. Over the course of about a week, the lump should gradually disappear. Contact your veterinarian if the lump shows signs of infection or if it hasn't gone away after a week.

There is a chance of infection any time that skin is punctured. Keep an eye on the site where your dog's injection was given. Watch for signs of infection such as increased redness, swelling, pain, or discharge. Infections can lead to more serious conditions if left untreated. If you notice that the spot where your dog had their injection is becoming inflamed and sore, contact your vet.

Sneezing & Cold Like Symptoms

Most of the vaccines recommended for dogs are given by injection however, the Bordetella bronchiseptica and parainfluenza virus vaccines are administered by drops or sprays into the dog's nose. Reactions to intranasal vaccines look much like a cold and include symptoms such as a runny nose, coughing, and sneezing. Expect your dog to recover from these symptoms within a day or two. If your dog does not recover within a couple of days or has more severe symptoms, call your veterinarian.

Soreness and Uncomfortableness

Following vaccinations, it is normal for a puppy to be sore and/or uncomfortable. When you try to pick up your puppy after their vaccinations, they may cry. Following the vaccination, your puppy may yelp. This, like the other side effects, should pass in a few days. If not, speak with your veterinarian.

Serious Reactions to Vaccinations

Vaccine reactions are usually mild and short-lived. However, in a few rare cases, more severe reactions may occur, necessitating immediate medical attention. Anaphylaxis is a severe allergic reaction characterized by facial swelling, vomiting, hives, itchiness, diarrhea, and breathing difficulties. Anaphylaxis in dogs usually occurs shortly after the vaccination, but it is important to note that it can occur up to 48 hours after the vaccination.

If your dog shows symptoms of anaphylaxis following their shots, call your vet immediately or contact your emergency veterinary clinic.

Preventing Reactions to Vaccines

Vaccines are essential in protecting your dog against a number of potentially fatal and contagious diseases. The risk of your dog having a serious reaction to a vaccine is very low. 

Be sure to let your vet know if your dog has a reaction to vaccines. Your vet may recommend that you skip a particular vaccination in the future.

When multiple vaccines are given at the same time, the risk of adverse reactions is increased, especially in smaller dogs. To help reduce your dog's risk of reacting to vaccines, your veterinarian may recommend getting your dog's shots over several days rather than all at once.

Contact our San Diego vets at Kearny Mesa Veterinary Center today, to find out more about vaccines and other preventive healthcare. 

New Patients Welcome

Kearny Mesa Veterinary Center is accepting new patients! Our experienced vets are passionate about the health of San Diego companion animals. Get in touch today to book your pet's first appointment.

Contact Us

(858) 279-3000 Contact