Vaccination for Pets: Typical and Possible Negative Side Effects

Perhaps more than any other medical advancement, vaccination has saved more lives. Vaccines today are extremely effective and safe. Many pets, however, endure moderate adverse effects after vaccination, which are comparable to those experienced by humans. 

These common, modest side effects rarely necessitate veterinary care intervention. We do not want one of our dogs to become ill. Vaccinations are crucial in preventing infections that are both unneeded and dangerous.

What are some of the most prevalent vaccine adverse effects?

It’s important to remember that these side effects are less dangerous than exposing your pet to serious infections if they aren’t vaccinated. Pet vaccinations are essential for your pet’s health since they have helped prevent infectious diseases and promote early detection and treatment of medical problems. Following immunization, some of the most common mild side effects include:

  • There is redness, slight swelling, and soreness at the immunization site.
  • Reduced levels of activity (fatigue)
  • Appetite loss 
  • Fever of a low intensity
  • Nasal discharge, sneezing, or other respiratory symptoms can appear 2 to 4 days after receiving an intranasal vaccine (vaccination delivered through the nostrils).

Get in touch with your vet here if these symptoms persist for more than 24 hours or if your pet is in pain. A tiny, solid nodule at the immunization site is also frequent in pets. Within 14 days, it should start to diminish and disappear. If the swelling persists for more than three weeks or looks to be getting larger or more painful, contact your veterinarian.

Are there any other possible adverse vaccination effects that I should be aware of in my pet?

Other, less common but more serious, adverse effects can appear minutes to hours after immunization. These reactions are considered medical emergencies, and you should seek veterinary help right once if you notice any of them:

  • Fainting or collapsing
  • Breathing problems
  • Coughing that is persistent and severe
  • Irritating pimples that are small, red, elevated, and itchy all over the body (hives)
  • Eyes, muzzle, or face that are swollen or bloated
  • Vomiting or diarrhea that doesn’t stop

Before getting your pet immunized, tell your veterinary surgeon near me if your pet has had any previous vaccine reactions, no matter how minor they may seem. Suppose you have any concerns that your pet may have a severe vaccine reaction, wait for 30 to 60 minutes after vaccination in your veterinarian’s office. 

Whether you have a dog, a cat, or both, keeping your animal’s vaccines up to date is critical to ensuring your animal’s (and your family’s) safety, as some animal diseases can be transmitted to humans.


One of our key responsibilities as responsible pet parents is to watch our pets’ health. The last thing we want is for one of our dogs to become ill. Vaccinations are crucial in preventing infections that are both unneeded and dangerous. 

Every year, the vast majority of the tens of millions of pets are vaccinated without incident. Monitor your pet and contact your veterinarian as soon as possible if there are any problems. Vaccines save numerous lives and protect our pet family members from deadly infectious diseases. Please discuss them with your veterinarian if you have any questions or concerns.