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Vaccine Reactions in Dogs

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

Why Are Vaccines Recommended 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 benefits of having your dog vaccinated far outweigh the risk of a vaccine reaction. However, some dogs do react to receiving their shots.

Common Reactions to Vaccines 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 usually far less dangerous than the illnesses that vaccines protect against.

Understanding the most common vaccine reactions in dogs, as well as what to do if your dog reacts to their shots, can make vaccination time less stressful for you and your pet.


Being lethargic is one of 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. This is a normal reaction to vaccinations in dogs, and the symptoms should be mild and only last a day or two. If your dog's reaction continues for more than a couple of days, contact your vet.

Lumps & Bumps

Vaccination-induced lumps and bumps are a common occurrence in dogs. A small, firm bump may form where the needle was injected into the skin after the vaccinations. This is a normal reaction, but it's important to keep an eye on the bump to make sure it doesn't continue to grow or show signs of infection, such as swelling, oozing, or increasing pain. Over a week, the lump should gradually disappear. Contact your veterinarian if the lump appears to be infected or if it hasn't gone away after a week.

Any time skin is punctured, there is a risk of infection. Keep an eye on the location where your dog received his injection. Increased redness, swelling, pain, or discharge are all signs of infection. If left untreated, infections can progress to more serious conditions. Contact your veterinarian if the area where your dog received their injection becomes inflamed and sore.

Be careful, your puppy may be yelping or crying when you try to pick him up after vaccination. Your dog may also have trouble walking after a vaccination, but it shouldn't be anything to worry about.

Sneezing & Cold Like Symptoms

The Bordetella bronchiseptica and parainfluenza virus vaccines are given by drops or sprays into the dog's nose, unlike the majority of the vaccines recommended for dogs. Intranasal vaccine reactions resemble a cold, with symptoms such as a runny nose, coughing, and sneezing. Within a day or two, your dog should be free of these symptoms. Call your veterinarian if your dog does not recover within a few days or has more severe symptoms.

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 or emergency vet immediately.

Preventing Reactions to Vaccines

Vaccines are essential in protecting your dog against several 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 reacts 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 vet may recommend getting your dog's shots over several days rather than all at once.

Contact our Mechanicsburg vets at Silver Springs Clinic today, to find out more about vaccines and other preventive healthcare. 

New Patients Welcome

Looking for a vet in Mechanicsburg PA? Silver Springs Animal Clinic is accepting new patients! Our skilled veterinarians are passionate about improving the health of Central Pennsylvania companion animals. Contact us today to book your pet's first appointment.

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