Some pet parents may notice a change in their pet's demeanor after they receive vaccines. In this article, our veterinarians at East Setauket discuss dog behavior changes that can occur after vaccinations, including rabies, and address common concerns of pet owners.

Vaccinations & Your Dog's Health

As a responsible pet owner, it's important to keep your dog's vaccinations up to date. Vaccinations are the most effective way to protect your pet from serious and contagious diseases. Our veterinarians recommend vaccines as an important part of your pet's annual health plan. While some people have concerns about the safety of vaccines, our veterinarians believe that the benefits outweigh the risks for most dogs.

Your dog's behavior might change after getting vaccinated. Here we look into some reasons why and what these changes could be.

Common Behavior Changes After Vaccinations

After getting their shots, many dogs may exhibit temporary changes in behavior that can vary from dog to dog. While these changes might seem worrying, it is important to know they are normal.

  • Decreased Appetite - Vaccinations can temporarily affect a dog's appetite. If your pet seems less interested in eating immediately after receiving shots, it is often nothing to be overly concerned about. Ensure they have access to fresh water and monitor their eating habits. If the reduced appetite persists for over a day or two, consult your veterinarian.
  • Mild Discomfort -Sometimes, dogs may feel a little discomfort or soreness at the spot where they were injected with a vaccine. They might show sensitivity when touched or avoid putting weight on the affected leg, especially if the vaccine was given in the leg region. However, this discomfort usually goes away within a few days.
  • Lethargy - Some dogs may experience lethargy or fatigue after vaccinations. This is a natural response as the body diverts energy to build an immune response. Allowing your dog time to rest and recover is crucial during this period.

It should be noted that changes in behavior after vaccination are more common in puppies than in older dogs. This is because puppies have developing immune systems that may react more strongly to the vaccine, leading to temporary changes in behavior such as lethargy or increased restlessness.

Factors Influencing Behavioral Changes

Different factors can contribute to your dog or puppy acting weird following their rabies or other vaccinations and shots. It is essential to consider these factors when evaluating your dog's response to the vaccines they recently received:

  • Vaccine Components -Vaccines have certain elements like adjuvants or preservatives that make them more effective and increase their shelf life. However, some dogs may experience allergic reactions to these elements, which can result in noticeable changes in their behavior. Therefore, you must discuss concerns with your veterinarian to ensure your pet receives the appropriate vaccines.
  • Stress and Anxiety - Veterinary visits, including vaccinations, can induce stress and anxiety in dogs. The anticipation of discomfort, strange environments, or unfamiliar people can trigger temporary changes in behavior. Comforting your dog with gentle reassurance and positive reinforcement can help alleviate stress during these visits.
  • Individual Sensitivity - Some dogs may be more susceptible to behavioral changes, while others may show no difference.

Side Effects of Vaccinations

It is common for dogs to experience mild behavioral changes following vaccinations, such as those listed above (lethargy, decreased appetite, or soreness at the injection site). These symptoms typically resolve within a day or two and are considered normal reactions to the vaccine.

When to Contact Your Vet

While most behavioral changes after vaccinations are normal and resolve within a few days, some situations may require veterinary attention. Contact your veterinarian if you notice any of the following:

  • Allergic Reactions - If your dog exhibits signs of an allergic reaction, such as excessive swelling, difficulty breathing, or vomiting, seek immediate veterinary care. Allergic reactions are rare but can be serious.
  • Uncharacteristic Behavior - If your dog displays unusual behavior unrelated to the common changes mentioned earlier, it is advisable to consult a veterinarian. The veterinarian can determine if the behavior is caused by vaccination or another health concern.
  • Severe or Prolonged Behavior Changes - If your dog's behavior changes are severe (such as a puppy being incredibly hyper after vaccination for an extended period), persist for a long time, or worsen over time, consult your veterinarian. These changes could indicate an adverse reaction or an unrelated underlying issue.

Are vaccines right for your dog?

Most dogs may exhibit minor changes in behavior after receiving vaccinations. However, these changes are typically nothing to worry about. By understanding the purpose of vaccinations, being mindful of any potential changes in your dog's behavior, and taking good care of your furry companion, you can ensure that your dog remains happy and healthy. 

You should speak to your veterinarian if you have any concerns about vaccinating your dog. They will consider your dog's individual health, habits, and potential risks to help you determine whether vaccinations are the right choice for your pet.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

If your dog is showing concerning signs, such as lethargy or vomiting after vaccinations, please contact our East Setauket vets as soon as possible.