what happens if a dog gets vaccinated twice

What Happens if a Dog Gets Vaccinated Twice?

Our dogs deserve a healthy life, but in an attempt to keep them healthy, we must be careful not to harm them. Vaccines for rabies, distemper, canine parvovirus, and canine hepatitis are important for every pup. But what happens if a dog gets vaccinated twice? Will second vaccination harm our pups?

Vets are always strict about vaccination and they’ll be sure to ask for your dog’s vaccination history before administering any vaccine. This is a professional practice because they understand the potential dangers of double vaccination. If your dog gets vaccinated twice, it could trigger some negative reactions. From immune system overload, allergic reactions, to sudden behavioral changes.

Image by J C from Pixabay

Immune System Overload

Dogs’ immune systems are consisting of two dominant classes that are interdependent and complementary. One of them is called cellular immunity, which acts as our pup’s primary immune defense mechanism. The second one is known as humoral immunity. It creates antigen-specific antibodies that serve as a secondary defense.

As soon as a part of these two classes becomes dominant, vaccines will go through the cellular immune system and excite the humoral system instead. When this happens, the humoral system dominates the major line of defense. After some time, this action reverses the dog’s natural immunological scheme, hence turning the immune system inside out.

Allergic Reactions

A study proved that younger pups of small breeds are at higher risk of vaccine reaction within the space of three days of being vaccinated. However, it’s a different case for multivalent vaccines, such as vaccines for parainfluenza, parvovirus, or Bordetella for kennel cough.

Although a dog’s allergic reaction may disappear within two days, it can cause severe problems within that period. That said, if your pooch shows any of the following signs for a long time, take her to the vet as soon as possible:

Respiratory Problems: Intranasal vaccinations may lead to discharge from the nose, mild cough, or sneezing.

Decreased Appetite: This may occur within two days after vaccinations. It often comes with depression and mild fever.

Anaphylaxis: The symptoms are diarrhea, sudden vomiting, facial swelling, drowsiness, seizures, and weak yet fast pulse. While anaphylaxis is rare, it is sometimes life-threatening and can lead to shock, respiratory or cardiac failure, and even death.

Reaction at the Injection area: Swelling, pain, redness, or irritation around the injection site.

Behavioral Changes

Vaccines contain both the actual virus that creates an immune response to its target—like rabies for instance—and an immune adjuvant that fuels the immune response. Vaccine adjuvants come with various toxic compounds like mercury, MSG, and aluminum. When vaccine adjuvants lead to prolonged activation, it may cause inflammation in the brain, leading to a pup’s behavioral change.

One of the reasons a dog can become suddenly aggressive is double vaccination. Multiple doses of immunization can lead to the following.

  • Irrational fears
  • Ferocity, agitation, rage, and violence
  • Hypersensitivity of all senses
  • Unwarranted erections
  • Involuntary urination
  • Gagging, coughing, swallowing liquids, or choking
  • Unprovoked attacks
  • Obsessive biting and chasing
  • Sensitivity to tight clothing, close places, and noise
  • Sexual drives and excessive focal licking
  • Aimless vocalization and wandering

Can Dogs Get Parvo After Vaccination?

Whether or not your dog has been vaccinated, it can still get Parvo. The virus has multiple strains and can reinvent itself. So, sadly, our dogs can easily catch the parvovirus at any time, even after vaccination.

While parvo is an awful disease, noticing the symptoms on time can help prevent long-term damages. So, what are the signs to look out for? Check if your dog has a fever. Is she lethargic? Is your doggie suffering from diarrhea and constantly vomiting? Does she have hypothermia, fluid distention for the intestines, tachycardia, or a weak pulse? All of these are sometimes signs that your pup is suffering from parvovirus.

Can a Vet Tell if a Puppy has had its Shots?

Regrettably, we can’t tell if a pup has taken its shot just by looking at it. As a rule of thumb, all domestic canines and felines should be vaccinated from a young age. This is crucial because as they approach adulthood, their immune system is not fully developed, meaning that they are exposed to lots of diseases.

Before getting a pup from a breeder, ensure to find out the vaccinations your pup has been given. The best way to get proof of your pet’s vaccination history is through its medical record.

However, there is another way to find out if a puppy has had its shots – through a vet. There are vaccine titers that can be carried out. This is a blood test conducted to check the antibiotic levels for a particular disease.

Can Dogs Get Two Rabies Shots?

While administering vaccines twice in a short period can be harmful to our dogs, double rabies shots might not always cause harm, except the dog is allergic to the vaccine. Nevertheless, it should be avoided because overvaccination can lead to harmful side effects.

If you’ve already vaccinated your dog against rabies when she was a pup, you don’t have to give her shots again. All you have to do is ensure it is stated in her medical records. As long as it’s a vet that administers the vaccine, you’ll be issued a certificate.

Importance of Vaccines in Dogs

Bacteria and viruses often lead to adverse effects in a dog’s system since they are not immune to them. If a virus attacks your pup’s body, it can make her ill because of the lack of antibodies to fight the attack and the shock in her system.

Vaccines mostly focus on boosting a dog’s immunity system to create antibodies to battle diseases that may come in the future. It creates antibodies that remain inside the pup’s body, to help recognize viruses. Vaccines contain antigens that lead to mild disease in a pup’s system by imitating the target disease organism.

The pup’s body in defense will start developing antibodies by spotting the invaders (antigens). With that, the pup’s immune system is strengthened enough to fight the disease organism whenever they invade.

Can a vet tell if a puppy has had its shots?
Image by David Mark from Pixabay

Types of Vaccines for Dogs

One of the vital things to consider before vaccinating your pooch is the countryside and local law. While some vaccinations are mandatory, some are not. Core vaccinations cater to severe life-threatening global diseases; hence, they are mandatory. There are several other vaccinations that aren’t mandatory but are peculiar to areas where the illness is common. They are known as non-core vaccinations.

Although core vaccinations are necessary by law for every pup in the world, the administration of non-core immunization is taken in consultation with a vet as well as their understanding of your area.

Core Vaccination and Diseases


Rabies is the deadliest disease common in dogs. What’s more, it can be transferred to humans through a dog scratch or bite. Dogs suffering from rabies go through acute encephalitis, which can result in failure of the dog’s nervous system and eventually death.

The disease can be treated through medication even before there are any signs. If left unattended, rabies becomes deadly. Rabies symptoms take a lot of time before it is seen. Your pooch may show its signs between 2 to 12 weeks of getting infected. Rabies can become evident in two forms; paralytic and furious.

While early signs are usually little signs of abnormality, infected dogs could die instantly after two days. If the dog becomes suddenly aggressive and tries to attack people, then it is experiencing furious rabies.

Meanwhile, dogs suffering from paralytic rabies, experience lethargy, a lack of coordination, and eventually complete paralysis. Although rabies vaccination is effective, it’s not 100 percent guaranteed. If an animal has bitten your dog—whether or not you know the animal’s medical state – take your dog to the vet to get him checked up.

Rabies Vaccination: Despite the severity of the disease, you can only administer rabies vaccination to your dog when she’s up to 12 weeks old. That said, the vaccination period varies based on region, so you’ll have to consult your vet first to be certain about when to give your dog her shots.

Canine Parvovirus

Canine Parvovirus is a contagious disease that can be contracted from the intake of an infected dog’s feces. It has an astonishing high death rate of about 91% in untreated cases, with younger pups being major victims. There are currently no effective medications to eradicate it unless it diminishes naturally. However, the parvo vaccine can prevent your dog from catching the disease.

Another good news is that canine parvovirus can’t be transferred from dogs to humans. If your doggie contracted parvovirus, she’ll display symptoms within ten days of infection. Parvovirus symptoms include vomiting, diarrhea, dehydration, shock, death, and lethargy. Pups infected by Parvovirus can transfer the disease to other dogs through their feces. Also, the virus even lives in a dog’s feces for up to six months.

Canine Parvovirus Vaccination (CPV): CPV is administered in a series of 4-way or 5-way vaccines called DHLPP or DHPP. This includes vaccines for Hepatitis, Leptospira, Distemper, Parainfluenza, and Parvovirus.

You have to inject your pup her first dose when she’s still below 6 weeks of age. After that, you can give her a total of three doses until she’s 16 weeks old. After the vaccination, you should provide him with an immune booster after a year.

Canine Hepatitis and Adenovirus Cough

Canine Hepatitis is a notorious disease in dogs caused by canine adenovirus type 1. A dog suffering from canine hepatitis can experience liver damage and swell in the liver will eventually lead to death. A dog can contract it if it ingests or licks the urine or feces of infected dogs.

It has critical symptoms including lethargy, fever, abdominal pain, tonsils, distention, pale color of eyes, and lack of appetite. A dog infected with this disease can die within two days of infection. However, if the dog does manage to fight the disease for a couple of days, it may defeat it and become completely immune to it.

Canine adenovirus type 2 is a virus closely related to hepatitis. However, it’s a little bit less fatal, and early vaccination reduces its severity. In extreme cases, it can lead to pink eyes, excessive coughing, nasal discharge, and inflammation while breathing and nasal passages.

Canine Adenovirus Vaccine (CAV): The Canine adenovirus-1 and canine adenovirus-2 vaccines help keep our dogs immune from adenovirus and hepatitis. Many veterinarians choose the canine adenovirus-2 vaccine since it delivers multipurpose effects.

The vaccine is administered in a sequence of 5-way or 7-way injections. The sequence starts when the pup is 6 to 8 weeks of age and receives it thrice until she’s 16 weeks old.

Canine Distemper

Canine Distemper is another highly infectious disease that is contagious through the air. The virus that leads to canine distemper in dogs is related to the one that causes measles in humans. The virus mostly damages the respiratory system, gastrointestinal system, tonsils, and nervous system.

Regrettably, there’s currently no cure for canine distemper. But there are medications to help relieve the symptoms, which in some cases cure the illness itself.

Canine Distemper Vaccination (CAD): The CAD vaccine protects dogs from Parainfluenza, Hepatitis, Parvovirus, and Leptospirosis. Your dog is supposed to get the first vaccine between 6 to 8 weeks of age. And subsequently between 10 to 12 and 16 months.

Non-Core Vaccination

There are several non-core vaccinations, such as Leptospirosis, Burgdorferi, and Bronchiseptica. Unlike the core vaccinations, these ones are not mandatory and are meant for local viruses. Vets only suggest them based on the region you and your pup live in.

vaccinating a dog with unknown history
Photo by freestocks.org from Pexels

Final Thoughts

There are so many questions that go into vaccinating a dog and they are all necessary for a healthy dog. Some dogs have allergies to the content of vaccines – the vet knows how to handle this. Also, you have to know your dog’s vaccination history because it determines whether or not your dog is getting vaccinated.

And if you’ve already vaccinated your pup and you’re not sure what happens if a dog is vaccinated twice, take the dog back to the vet.

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