Understanding Dog Behavior Change After Vaccination – Why and What To Do?

Are you concerned about how your dog will react after getting vaccinated? Vaccines are an important part of keeping your pup healthy, but they can also cause a change in behavior. In this blog post, we’ll discuss how your dog may act differently after receiving a vaccine, the possible causes of these changes, and how to help your pup adjust.

Vaccines can cause a range of reactions, from mild to severe. Some dogs might become more anxious or nervous, while others may become lethargic or disinterested in activities. Some may even show signs of aggression, such as growling or barking.

These changes in behavior may be due to the stress of the procedure, the ingredients in the vaccine, or the reaction to the vaccine itself. It is important to be aware of these behaviors and how to help your pup adjust. If you notice any changes in your pup’s behavior, contact your veterinarian to discuss possible treatment options.

In most cases, the behavior should resolve on its own after a few days. In the meantime, try to provide your pup with extra love and attention to help them relax. If the behavior persists, your vet may suggest medications or other forms of treatment. Ultimately, it is important to remember that vaccines are necessary in order to keep your pup healthy and safe.

Why Has Your Dog’s Behavior Changed Since Vaccination?

Not Feeling Well

After a dog is vaccinated, he may experience some behavior changes. He may seem tired or sleepy and less active than usual. He may also seem irritable or uninterested in playing, or he may be clingy and want to be around his owner more. These behavior changes may be due to the stress of the vaccination, or to the body’s natural response to the vaccine.

In any case, it is important to keep an eye on your dog and make sure he is comfortable and not in pain. If he continues to seem unwell for more than a few days, it is best to contact your vet for a checkup.


Hypersensitivity reactions and behavioral changes can occur after a dog is vaccinated. Dogs may become more anxious, more sensitive to sounds, startle more easily, or may even become aggressive. These changes may last for a few hours or days after the vaccination, or may even last for weeks or months.

The changes are usually mild and will go away on their own, but if they become more severe or last for a long period of time, it is important to talk to a veterinarian. Vaccinations are an important part of a pet’s health, but it is important to watch for any changes in behavior after the vaccination is administered.

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An Allergic Reaction

When a dog is vaccinated, their behavior may change as a result. Dogs may become more lethargic or even sick for a short period of time after receiving the vaccination. This is because the body is trying to adjust to the new substances in the vaccine.

In some cases, a dog may experience an allergic reaction to the vaccination, which can cause them to become more anxious or irritable. It is important that owners keep an eye on their dog for any signs of an allergic reaction and contact a veterinarian if any concerning changes in behavior are observed.


Inflammation and pain following vaccination can cause changes in a dog’s behavior. Dogs may become less active, more anxious, and more irritable due to the pain and discomfort caused by the injection.

They may also become clingier and more sensitive to touch or noise. If a dog is displaying signs of pain or discomfort after vaccination, it is important to speak with your vet about possible treatments to reduce the discomfort. Additionally, making sure your dog is getting enough sleep, exercise, and mental stimulation can help reduce the stress of vaccination and its side effects.

Is It Normal for a Dog’s Behavior to Change after Vaccination?

Yes, it is normal for a dog’s behavior to change after vaccination. After receiving a vaccine, dogs may experience some mild side effects such as lethargy, decreased appetite, and reduced activity levels. In addition, some dogs may become anxious, fearful, or display signs of aggression due to their discomfort.

This is usually temporary and will resolve itself within a few days. However, it is important to monitor your dog’s behavior after vaccination and contact your veterinarian if any changes seem concerning.

Will Your Dog’s Behavior Return Following Vaccination?

Yes, it is possible that your dog’s behavior may return to normal following vaccination. After a dog has been vaccinated, it may experience some temporary side effects such as lethargy, mild fever, and slight discomfort.

These are all normal signs that the body is reacting to the introduction of the vaccine and will usually resolve within 1-2 days. If your dog does become lethargic or uncomfortable after vaccination, it is recommended that you speak with your veterinarian as they may prescribe a mild pain reliever to help your dog feel more comfortable. After the side effects of the vaccine have resolved, you should see your dog’s behavior return to normal.

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How to Support Your Dog after Vaccination

After your dog receives a vaccination, it is important to keep a close eye on its behavior and general health. To help your pup feel more comfortable, try to keep your pet in a quiet, stress-free environment and offer them plenty of breaks to rest and relax. Additionally, it is important to follow the following steps:

Treat Any Allergic Reactions

If a dog experiences an allergic reaction after being vaccinated, it is important to contact your veterinarian immediately. Allergic reactions can range from mild to severe and can include symptoms such as hives, swelling of the face, vomiting, and difficulty breathing. It is important to monitor your dog closely after being vaccinated and to look for any changes in behavior.

If you notice any of the symptoms mentioned above, or if your dog seems to be unusually lethargic or irritable, it is important to contact your veterinarian right away. Treatment for allergic reactions may include antihistamines, steroids, and other medications.

Request Pain Relief Medicine

After a dog is vaccinated, it is common for them to experience pain and discomfort. To alleviate their discomfort, it is important to provide them with pain relief medicine as soon as possible. This will help reduce the pain and help the dog to adjust better to the vaccination. Pain relief medicine will also help to reduce the risk of any complications due to vaccination.

Additionally, it can help the dog to remain calm and relaxed during the recovery period. By providing the dog with pain relief medicine, you can ensure that they are feeling well and that their behavior changes are the result of the vaccination, rather than the pain.

Provide Relief If He Has a Fever

If your dog has a fever after a vaccination, it is important to take him to the vet for a checkup. In most cases, the fever is a sign that the body is fighting off the infection, and a simple fever reducer like acetaminophen or ibuprofen can provide relief. It is important to monitor your dog closely and make sure his temperature does not get too high.

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If your dog’s temperature is over 104 degrees Fahrenheit, you should contact your vet right away. If the fever persists, the vet will likely want to run tests to determine the cause of the fever, which may include blood work or urinalysis. With proper care, your pup should make a full recovery and his behavior should return to normal soon.

Provide the Space He Needs to Recover

After a dog receives a vaccination, it is important to provide them with the space and time they need to recover. Dogs may become lethargic, and may even experience some minor pain and discomfort.

It is important to avoid too much physical activity, or overstimulating activities, during this time, as it can lead to further stress on their body while they attempt to recover. Keeping their environment calm and quiet, and offering comforting cuddles and reassurance, is the best way to ensure they recover quickly and feel secure.

Do’s and Don’ts after Dog Vaccination

After your dog has received a vaccination, it is important to keep an eye on its behavior for the next few days. While most dogs won’t show any visible signs, some may be lethargic and have a loss of appetite. It is also not uncommon for them to be more sensitive to touch in the injection area.


  • Monitor your dog’s behavior, but don’t overreact if they seem a bit off
  • Provide plenty of comfortable bedding and rest time
  • Offer a warm meal if they have a decreased appetite
  • Keep your dog away from other animals until the vaccine has had time to take effect


  • Don’t subject your dog to overly strenuous activities or extreme temperatures
  • Don’t bathe your dog for at least two days after vaccination
  • Don’t give your dog any human medications or supplements without consulting your vet
  • Don’t let your dog socialize with other dogs until after the vaccine has taken effect.


In conclusion, the behavior of dogs can change after vaccination, either positively or negatively. Vaccines help protect against many diseases, but can also cause side effects such as lethargy, loss of appetite, and changes in behavior. If you notice any behavioral changes in your dog after vaccination, it is important to contact your veterinarian to discuss these changes. With proper care and monitoring, your dog should eventually return to their normal behavior.

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