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Why Is My Dog Shaking After Shots? Understanding Canine Vaccine Reactions

Why Is My Dog Shaking After Shots

After taking their dog to the vet for vaccinations, some pet owners may question, “why is my dog shaking after shots?” While it can be alarming to see your dog shaking after shots, it’s actually a relatively common occurrence. 

Understanding why this happens and what you can do to help your pet feel better can ease your worries and ensure your dog stays healthy. You can even help your dog calm down post-vaccination with their favorite relaxing dog bed and other soothing techniques. 

If you’re wondering why your dog is shaking after shots, there are a few reasons why this may be happening. In some cases, the shaking may be a normal reaction to the injection itself. In other cases, it may be a sign of a more serious reaction. We’ve consulted the Vaccine Guide for Dogs and Cats by Catherine Diodati to shed more light on the matter. 

Note: there is a lot of misinformation on the internet about vaccinations, and there is a growing movement against vaccinating dogs. To be clear, we support responsible dog ownership and that means controlling infectious disease among dogs with scheduled vaccines. 

Some dogs may have a reaction like shaking (or extremely rarely, an allergic reaction) to a vaccine. However, diseases like Parvo, Distemper, and Rabies are deadly and will cause far more suffering than an injection. 

So before we get into why a dog might be shaking after an injection or a vaccination, let’s first look at vaccinations for dogs and why they are so essential.

Key Takeaways

  • Vaccinations are important to keeping your dog healthy, but they can have side effects.
  • Shaking or trembling is a common side effect of vaccinations in dogs.
  • Understanding the potential causes of shaking after shots can help you determine whether your dog needs medical attention or simply some extra TLC.

What are Vaccinations for Dogs?

What are Vaccinations for Dogs?

Vaccinations for dogs are preventive measures taken to protect dogs from infectious diseases by stimulating their immune system to produce antibodies. The vaccines contain small amounts of weakened or dead viruses, bacteria, or other disease-causing organisms that are not harmful but can still trigger an immune response.

These shots are critical in preventing deadly diseases like Parvovirus, which has a mortality rate of 91% without immediate medical attention.

What Happens During Vaccinations?

During vaccinations, a veterinarian injects a vaccine into a dog’s body using a needle. The vaccine enters the dog’s bloodstream, and the immune system recognizes the foreign substance as a threat.

The immune system then produces antibodies to fight the virus or bacteria. In other words, vaccines work by imitating a disease to engage the body’s natural defenses. This way, when the disease comes, the body is better equipped to deal with it.

Why are Vaccinations For Dogs Important?

Vaccinations are essential to protect dogs from infectious diseases that can cause severe illness or even death. Vaccinations reduce the spread of diseases and help protect not only individual dogs but also the entire dog population. Vaccinating dogs can prevent the spread of infectious diseases and protect the community’s health.

It is important to note that vaccinations do not guarantee that a dog will never get sick. However, they significantly reduce the risk of contracting infectious diseases and can help lessen the severity of the disease if contracted. For maximum efficacy, receiving all the shots is the best way to prevent vaccinated diseases.

But if shots for dogs are so essential, why is your dog shaking?

Why is My Dog Shaking After Shots? Common Reasons

Why is My Dog Shaking After Shots?

Dogs shaking after shots is a common occurrence and is usually nothing to worry about. The shaking is often a natural reaction to the injection and is a sign that the dog’s immune system is responding to the antigen in the shot. However, there are other possible reasons why a dog may shake after receiving a shot.

Pain and Discomfort 

One reason for dog shaking after shots is pain or discomfort. The injection site may be sore, or the dog may be experiencing inflammation. Even adults fear needles, so we wouldn’t expect any less from dogs.

Allergic Reaction 

 In some cases, the shaking may indicate an allergic reaction to the vaccine. If the shaking persists or is accompanied by other symptoms such as lethargy, loss of appetite, or difficulty breathing, it is essential to seek medical attention from a veterinarian.

The Pup is Stressed 

Another reason for dogs shaking after shots is stress or anxiety. Dogs may become anxious or frightened when handled by a veterinarian or injected with a needle. These strong emotions could also explain why your dog’s back leg is shaking, even if that’s not the injection site. Some breeds, Chihuahuas, are even known for shaking when they feel stressed.

Owners can help prevent this by calming their dogs before and after the vaccination. Petting and cuddling the dog or using a blanket to keep them warm can help to calm them down. 

Your Dog Was Already Shaking Before The Vaccine

In some cases, dogs may have an underlying health condition that coincidentally causes shaking around the same time as receiving vaccines. It’s essential to consider other symptoms and consult with a veterinarian if you have concerns.

Additionally, some breeds shake more than others, as you’ve probably observed in Chihuahua shaking

Low Blood Sugar

In rare cases, dogs may experience a temporary drop in blood sugar levels (hypoglycemia) after receiving vaccinations. This can result in shaking, weakness, or other symptoms. However, this is more commonly seen in small toy breeds or puppies.

A study showed that the Bordetella pertussis vaccine specifically led to lower glucose levels in certain dogs. Toy breeds are especially susceptible to hypoglycemia, especially if it’s been long since they last ate.

It is important to ensure that the dog is hydrated after receiving a shot. Providing water and monitoring their behavior can help to prevent dehydration. In addition, owners should keep an eye on their dog for the next few days to ensure that the shaking subsides and that the dog is not experiencing any other symptoms.

What are the Side Effects of Vaccinations for Dogs

Vaccinations are an essential part of keeping your dog healthy and protected from diseases. However, like any medication, vaccines can have side effects. Some of the normal side effects of vaccinations in dogs include:

  • Mild fever
  • Swelling or redness at the injection site
  • Decreased appetite
  • Lethargy or tiredness

These side effects are usually mild and resolve on their own within a few days. In most cases, they are not a cause for concern and do not require any treatment.

What are the Abnormal Side Effects of Vaccinations?

What are the Abnormal Side Effects of Vaccinations?

While most dogs experience only mild side effects after vaccinations, some may have more adverse reactions. It’s important to note that adverse reactions to vaccines in dogs are rare, and the risk of adverse reactions don’t outweigh the risks of diseases like parvo or rabies. Nevertheless, these abnormal side effects can include:

  • Allergic reactions: Some dogs may be allergic to certain vaccine components and can have an allergic reaction. Signs of an allergic reaction include vomiting, diarrhea, discomfort, and shaking or shivering.
  • Adverse effects: In some cases, dogs may experience adverse effects after vaccinations, such as nervous system problems, tremors, or seizures.
  • Vaccine reactions: Some dogs may react to the vaccine itself, which can cause symptoms such as fever, lethargy, and swelling at the injection site.
  • Rabies vaccine reactions: The rabies vaccine is known to cause more side effects than other vaccines. Dogs may experience vomiting, diarrhea, or even shock after receiving a rabies shot.
  • Distemper vaccine reactions: The distemper vaccine can also cause side effects such as shaking or trembling, cold or fever, and lethargy.

Contact your veterinarian immediately if your dog experiences any abnormal side effects after vaccinations. Sometimes, treatment may be necessary to alleviate symptoms and prevent further complications.

Generally, it’s important to monitor your dog closely after vaccinations and report any unusual symptoms to your veterinarian. Most side effects are mild and resolve on their own, but it’s always better to be safe than sorry.

How Long Do Shots Side Effects Last in Dogs?

Most vaccine side effects in dogs are mild and resolve within one to two days. However, some dogs may experience more severe reactions lasting several days or weeks. If your dog is experiencing prolonged side effects, contact your veterinarian.

Dogs with swellings after vaccinations can take up to two weeks for the swelling to reside. However, this doesn’t necessarily mean your dog is in pain the entire time.

Why is My Dog Sick 4 Days After Vaccination? 

Dogs ordinarily display symptoms mimicking a cold, like a runny nose, coughing, and sneezing. However, dogs remaining sick four days after vaccination may have unexpected reactions to the shots. It’s best to consult your vet if your dog’s vaccine-related sickness persists this long. 

Also, unrelated illnesses, exposure to contagious diseases, pre-existing health conditions, or stress-related effects could contribute to your dog’s sickness. It is advisable to consult your veterinarian to determine the underlying cause of your dog’s illness and to receive appropriate diagnosis and treatment.

Help! My Puppy is Shaking While Sleeping After Vaccination

If your puppy is shaking while sleeping after receiving a vaccine, it is possible that the shaking is unrelated to the vaccination. Shaking during sleep can occur due to various reasons, such as dreaming, muscle twitches, changes in body temperature, or even normal physiological processes. 

If your dog has a fever, or begins showing massive behavioral changes, or seizures, then there may be cause for concern, so watch your dog closely for other symptoms.

Vaccines rarely cause twitches and shaking when sleeping. However, you can consult your vet if you’re still unsure of what sleep-shaking means.

Are Certain Breeds More Prone to Vaccine Reactions?

Many studies have suggested that certain breeds, like dachshunds, are more likely to experience vaccine reactions. Research has shown that Dachshunds, Pugs, Boston Terriers, Miniature Pinschers, and Chihuahuas had a higher incidence of vaccine-associated reactions. 

Others even suggest that other breeds, like Old English Sheepdogs, Akitas, and Weimaraners, have increased vaccine sensitivity. 

What To Do If Your Dog Has Reaction to Shots?

If your dog is shaking after shots, you should monitor him closely and contact your veterinarian if you notice any other symptoms. Your vet may recommend giving your dog a mild pain reliever or anti-inflammatory medication to help ease any discomfort.

Depending on the severity of the reaction and your veterinarian’s recommendations, adjustments to your dog’s vaccination plan may be necessary. Your veterinarian may suggest alternativ-e-archive vaccines, modified schedules, or additional precautions in the future. 

Frequently Asked Questions

Does the rabies shot cause shaking in dogs?

Yes, the rabies shot can cause shaking in dogs. Shaking may be a sign of a mild reaction to the vaccine or a more severe allergic reaction. If your dog is shaking after receiving the rabies vaccine, contact your veterinarian immediately.

Why Has My Dog’s Behavior Changed After Vaccination?

The stress and anxiety associated with veterinary visits and the vaccination process can contribute to behavior changes. Some dogs may become more anxious, clingy, or seek comfort from their owners. On the other hand, some dogs may exhibit a decrease in activity or show signs of being more subdued.

Why is my dog acting weird after Distemper Shot?

Dogs may act weird after getting vaccinated due to the vet visit’s stress, the injection’s discomfort, or a reaction to the vaccine. Some dogs may become lethargic, while others may become hyperactive or restless. Contact your veterinarian if you notice any unusual behavior after your dog receives a vaccine.

Final Thoughts 

Dogs shaking after shots is a common occurrence and is usually nothing to worry about. However, if the shaking persists or is accompanied by other symptoms, it is important to seek medical attention from a veterinarian. Owners can help prevent stress and anxiety by calming their dogs before and after the vaccination, providing water, and monitoring their behavior to ensu re they are hydrated and comfortable.


Tamsin De La Harpe


Tamsin de la Harpe has nearly two decades of experience with dogs in rescue, training, and behavior modification with fearful and aggressive dogs. She has worked closely with veterinarians and various kennels, building up extensive medical knowledge and an understanding of canine health and physiology. She also spent two years in the animal sciences as a canine nutrition researcher, focusing on longevity and holistic healthcare for our four-legged companions.

Tamsin currently keeps a busy homestead with an assortment of rescue dogs and three Bullmastiffs.

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