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Vaccine Reactions in Dogs: Everything You Should Know

Vaccine Reactions in Dogs: Everything You Should Know

Vaccinating your dog is usually beneficial, but some may experience negative reactions. Our veterinarians in Benicia have listed common reactions and what to do if it happens.

Why should I get my dog vaccinated?

By having your dog vaccinated early in life and bringing them in regularly for booster shots as an adult, you'll provide them with their best opportunity to live a long, healthy life. Diseases such as hepatitis, rabies, and parvovirus can be very serious and even fatal, especially in puppies. Vaccines keep these preventable diseases from developing in the first place, which is always preferable to treating them once they exist in your pet. 

Does my dog need all the available vaccines?

Before recommending which immunizations are suitable for your dog, your veterinarian will consider your dog's breed, age, and lifestyle to identify any potential risk factors.

What are the most common reactions to vaccines in dogs?

All medical procedures have an inherent risk of adverse reactions, and vaccines are no different. While seeing your pet have a reaction to vaccines can be upsetting, it's essential to remember that most reactions are short-lived and mild. Understanding the signs of a reaction and what to do if your dog has a reaction can help to make vaccination time less stressful for both you and your dog. 


By far, general feelings of lethargy and discomfort are by far the most common reactions dogs have when getting their shots. A mild fever may accompany these. When we experience the same sensations in our bodies, many of us would describe this as feeling 'off.' This reaction for your dog means the immune system is working well and responding appropriately to the vaccine. These mild symptoms are normal and will likely only last a day or two. If your dog is still feeling lethargic after their shots or isn't feeling and acting back to normal within a couple of days, contact your vet. 

Lumps & Bumps

After receiving vaccinations, dogs may develop small bumps at the site where the needle was injected into the skin or muscle. This is a common reaction and is caused by the immune system responding to the irritation. However, it is important to monitor the area for any signs of infection, such as swelling, redness, discharge, and pain. If these symptoms occur, it is important to contact your veterinarian, as untreated infections can lead to more serious conditions.

Sneezing & Cold Like Symptoms

Although most vaccines are administered through injection, the Bordetella Bronchiseptica and parainfluenza virus vaccines are administered through drops or sprays into the dog's nose. The symptoms that may occur after receiving these vaccines can resemble a common cold, which include coughing, sneezing, and a runny nose. It is typical for dogs to recover from these symptoms within a day or two. However, if your dog experiences severe symptoms or does not recover within a couple of days, it is recommended that you contact your veterinarian.

Trouble Walking

Your dog's injection site may be painful or swollen after they receive their shots. Therefore, you may notice some limping and paralysis. Rear (posterior) end paralysis - a condition most common in dogs that have had a Rabies shot - means that a dog's hind or back legs cease functioning as a result of a reaction. 

As unnerving as this sounds, the paralysis is not permanent and will probably improve on the tenth day after symptoms first appear. If your dog is having trouble walking after getting his shots, monitor any paralysis or limping symptoms closely and ask your vet for advice. 

Yelping or Crying

It's normal to feel worried if your puppy yelps when you pick them up after their vaccination. You might be inclined to ask your vet, "Why is my puppy crying when I pick him up after his shots?" However, this is a natural response, and there's no need to panic. Usually, the yelping will stop within a few hours or a day or two at the most. If the yelping continues beyond 48 hours, contacting your vet is best.

Serious Reactions to Vaccinations

Although most vaccine reactions are mild and short-lived, there are rare cases where severe reactions may occur and require immediate medical attention. Anaphylaxis is a severe allergic reaction that can cause symptoms such as facial swelling, vomiting, hives, itchiness, diarrhea, and difficulty breathing. This reaction usually occurs shortly after the injection, but it can happen up to 48 hours after the vaccine has been given. If your dog exhibits any of these symptoms, it is essential to contact your veterinarian immediately or an emergency veterinary clinic.

Can I prevent my dog from having a reaction? 

Ensuring your dog's long-term health is important, and vaccines can help with that. Fortunately, the likelihood of your dog having a serious reaction to a vaccine is very low. However, if your dog has reacted negatively to a vaccine before, it's important to inform your veterinarian.

They may suggest skipping certain vaccinations to prevent future side effects. It's worth noting that the risk of side effects from multiple vaccinations increases, especially in smaller dogs. To reduce this risk, your vet might recommend administering your dog's shots over several days instead of all at once.

To learn more about vaccinations and preventive healthcare for your dog, contact our Benicia vets today to book an appointment.

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