We are reader supported, we earn a small commission when you buy something using our retail links.

Dog Vaccine Reactions: Side Effects and Risks Associated with Dog Vaccinations

At A Glance

Most side effects are mild. However, if you’re getting your dog vaccinated, it’s a good idea to become acquainted with possible side effects and what to do just in case.

This article will prepare you for any eventuality.

Last Updated on: Jan 29, 2022

Just like human vaccinations, dog vaccinations are administered during the course of a dog’s life, from puppyhood to adulthood. Vaccines are injections that introduce traces of a virus to provoke a natural immune response and develop antibodies. According to the American Veterinary Association, pet vaccinations have saved millions of animal lives. However, there are some dog vaccine reactions that you must know about.

If you are among the 44% of Americans that have pet dogs, there are many reasons to vaccinate your pets. Do dog vaccinations have side effects? Definitely. Dog vaccine reactions are sometimes mild and other times severe. When should you be worried?

custom oil-painted dog portraits by Poshtraits

A dog getting vaccinated

Side Effects and Risks Associated with Dog Vaccinations

Vaccines are important, but they do come with side effects. On rare occasions, you can have a very sick dog after a shot. What is the best way to manage this? 

After having your pet vaccinated, the best way to deal with possible side effects is to monitor your pet closely and to be aware of the dog vaccine reactions. There are two types of vaccine reactions: type 1 and type 2. While type 1 reactions are mild, type 2 reactions are more serious.

Type 1 Vaccine Reactions

These reactions are mild and usually go away within a day or two. You should go back to your vet if these symptoms become worse or do not disappear after two days.

Loss of Appetite and Decreased Activity

It’s normal for your usually active puppy to be less active after being vaccinated. Your puppy may also have a decreased appetite. Expect this to last for a day or two.

These side effects are nothing to be worried about. Encourage your dog to go out even when feeling sluggish. Monitor your puppy’s progress until its appetite and activity levels are back to normal. After one to two days, your puppy should be behaving as before.

Lethargy and Soreness

This is the most common side effect of vaccines for dogs. Lethargy means your dog may experience a loss of energy and liveliness. A mild fever could also accompany lethargy and soreness. This is a normal reaction. Your dog should recover in a day or two.

If side effects continue for more than two days, talk to your vet. Your vet can administer certain drugs to help with the fever and soreness.

Sneezing and Coughing

Most vaccines are administered through injections. However, there are a few that are administered through drops or by spraying the dog’s nose. One example is the vaccine that protects against the parainfluenza virus.

After intranasal vaccines are administered, dogs may cough, sneeze, sniff or develop a runny nose for a couple of days. This is normal unless it becomes too much and doesn’t disappear after some time. Call your veterinarian if the coughing and sneezing lasts beyond five days.

Soft Lump on the Spot

Some swelling may develop on the spot where the vaccine was administered. This is common even for humans. The lump is not supposed to be painful or grow after some time. It is also not supposed to ooze out foreign substances.

After some time, lumps disappear on their own. If you find a lump at the injection site, you don’t need to worry. However, if it persists, is painful, or keeps growing bigger, take your dog to your vet.

A dog with an anaphylactic reaction

Type 2 Vaccine Reactions

Reactions to Type 2 vaccines are worse than Type 1 vaccines. If you notice any of these reactions in your dog, you should seek help from your vet immediately.


Dogs may experience allergic reactions after an injection. This is because certain dogs are allergic to certain medications. The most common allergic reaction is called anaphylaxis. Unlike other side effects, anaphylaxis can be scary. Its symptoms include swelling, itchiness, diarrhea, vomiting, and breathing difficulties. If you start noticing any of these symptoms, immediately go back to your veterinarian to have your dog looked at.

Bacterial Infection

Unfortunately, bacteria can penetrate your dog’s skin and affect healthy tissue. If you notice swelling and discharge, it’s a red flag that bacteria somehow entered your dog’s skin. Seek medical help for your dog immediately before things get any worse.

A dog getting his vaccine shots

How To Prevent Reactions

Animal health professionals will tell you that vaccines are vital for your dog. They also admit that vaccines can have side effects, some of which are mild and some of which are severe.

Unfortunately, it’s impossible to tell which vaccines will cause serious side effects. However, there are ways to manage and minimize side effects.

A puppy getting vaccinated

Managing and Minimizing Side Effects

There are a couple of ways you can manage and minimize side effects:

Observe Your Pet Closely for Reactions

Even when mild, reactions should not manifest for longer than 48 hours. You should also watch out for any serious reactions. These include extreme coughing, shortness of breath, seizures, and vomiting.

A dog’s vaccine reaction lump should also disappear after two days of being vaccinated. Take your pet to the vet if side effects are serious or last for longer than 2 days.

Minimize Vaccinations

It’s best to minimize vaccinations to those that are absolutely necessary especially if your dog’s vaccine reactions are serious. Your vet will probably advise annual vaccinations but your dog may need less of them.

One thing you can do is to check if certain vaccinations are still in effect for your dog. This can be done with titer tests. Titer tests allow you to cut down on vaccinations and their side effects in a responsible manner.

Have a Vaccination Schedule Tailored to Your Dog’s Needs

Your vet will most likely tailor a vaccination schedule that caters to your dog’s specific needs. However, it’s best if you’re aware of this and can bring it up during your next appointment.

Look up dog vaccination schedules and ask your vet about them. If your pet has sensitivity to vaccines, mention it. This helps your vet can come up with a vaccination schedule that’s best suited for your dog.

A puppy getting his vaccine shots

When To Seek Care

What can I give my dog for an allergic reaction to shots? Do not administer any medications on your own and without advice from your vet.

Remember, with type 1 side effects you can wait until 48 hours have passed before bringing your dog to the vet. If they continue after this period, go to your vet.

If your dog is manifesting type 2 side effects such as your dog being short of breath after a vaccine, seek immediate medical attention.

A puppy getting vaccinated

Frequently Asked Questions

Here are some FAQs for dog vaccinations.

How Often Does My Pet Need To Be Vaccinated?

Your veterinarian with input from you is in the best position to make recommendations for your dog’s vaccination schedule. Most states recommend that you start vaccinating your pet early.

Most vaccines are given during the first years of a dog’s life. Booster vaccines are administered a year after to ensure the effectiveness of the vaccines administered.

What Happens if My Pet Misses a Vaccination?

You can still get your dog vaccinated if you miss the vaccination. However, if a significant amount of time has gone by, talk to your veterinarian.

Your vet will advise on whether the vaccine cycle should be started over again. It is important that you follow your dog’s vaccination schedule as much as possible.

Why Should I Get My Dog Vaccinated?

There are major benefits to vaccinating your dog. Here are some of them:

  • To prevent your pet from acquiring and transmitting diseases
  • To avoid expensive treatments for preventable illnesses
  • It is required by law
  • Vaccinations are required by dog parks, doggie daycares, and pet-friendly hotels.


How Much Do Vaccines Cost?

On average, basic vaccinations cost between $30 and $70. Booster vaccines cost between $20 and $40.

However, the costs may vary from one provider to another. It is a good idea to get your pet insured as many vaccines are already covered by the top pet policies.

A dog getting his vaccine shots
Ensure your dog gets its vaccines and monitor it closely after for any side effects. Most dog vaccine reactions are mild and short-term. However, if symptoms persist or appear to be serious, please seek the advice of a vet immediately.

Despite potential side effects, vaccines are integral for the health of our four-footed friends. You’ve done the right thing by learning about side effects and how to manage them. Most likely, your canine companion won’t suffer any side effects, but just in case, you’ll be ready.



Meet Paul, a devoted dog dad to the delightful French Bulldog, Cofi. With a flair for humor and a deep understanding of Frenchie quirks, Paul brings a lighthearted touch to his writings. His relatable stories and practical insights are a blend of laughter and valuable advice and resonate with fellow dog owners.

Through his words, Paul aims to celebrate the joys and challenges of being a dedicated pet parent, reminding you that life is simply better with a four-legged, snorting sidekick by your side.