Parvovirus is a disease feared by dog parents, and for good reason. Prevalent since around 1970, Parvovirus is a highly contagious disease that affects all ages, but especially puppies aged under 6 months. The disease can take hold quickly and signs can be seen in as little as three days. Sadly Parvovirus can cause death. This is why veterinarians so passionately recommend vaccinating your dog against Parvovirus. 

Key Takeaways:

  • Parvovirus is a highly contagious disease that affects dogs, especially puppies under six months.
  • Vaccination is the best thing dog owners can do to prevent Parvovirus in their pets. It is not 100% effective, but it reduces mortality rates significantly.
  • A complete vaccination schedule is necessary for puppies to have full immunity against Parvovirus.

Parvovirus Vaccinations

Vaccinating your dog is one of the single best things you can do to prevent Parvovirus in your pet. Vaccination has reduced mortality rates significantly across the globe in areas of high vaccination rates against Parvovirus.

When most of the dog population is vaccinated, it reduces the transmission of disease. This is because more pets are able to mount an immune response and fight off the virus, rather than succumb to it and continue to shed more virus in their feces, thus increasing the potential for exposure to more dogs. 

Can a Vaccinated Dog Get Parvo?

Although vaccination is effective at preventing Parvo, even vaccinated dogs may occasionally be infected by Parvovirus and develop disease. The vaccine provides immunity against the virus, but it is not 100% effective. 

Here's a list of reasons why they sometimes don't work:

Incomplete Vaccination Schedule 

Puppies need multiple vaccinations to get full immunity. When puppies are born they have a small amount of immunity passed through from their mother, but this fades quickly with time. We boost these immunity levels by repeat vaccinations.

Vaccinations in puppies should be given every four weeks from the age of 6 weeks until 16 weeks and an annual booster thereafter. If your puppy stops receiving vaccines too early in this program or misses a vaccine, it can reduce their body’s ability to fight off the infection. 

Failure to Develop Immunity to Disease 

It’s well documented in human and animal medicine that not every individual who gets a vaccine will develop the correct immune response. When we give a vaccine, it’s up to the individual body to recognize the virus as dangerous and create an immune response to this virus. When we give a vaccine, it’s harmless so cannot cause disease, but not everyone will develop antibodies to fight off the virus if it enters the body again. 

Recently, dog blood tests have been developed to test if immunity has been developed, however, they are still expensive so not mainstream yet. It’s hoped in the future, a blood test will be done before vaccination. This will check if your pet still has the required level of immunity or if they need a top-up with the vaccine. 

Overwhelming Viral Load 

Even if your puppy is vaccinated, and has created antibodies to fight off the infection, she can still become infected with the virus. If you live in a high-risk area or have met a Parvovirus-infected dog, your puppy can pick up a large amount of virus material from this interaction. If the virus enters the body in large numbers and manages to replicate before the body has a chance to respond, the virus can cause disease. 

Immune Suppression 

Rarely, do puppies have other diseases that lower or remove the immune system. Vaccinations stimulate the immune system to make a response. In a disease that destroys the immune system, there is nothing left to fight the disease. This is how some dogs can become infected with Parvovirus, and it’s not related to vaccine failure or lack of vaccine immunity although it may initially appear this way. Dogs who have diseases of the immune system such as cancers are often very sick and the chances of recovery are much lower. 

What are the Signs of Parvovirus in Dogs?

Signs are noticeable and get significantly worse with time. If you see any of the signs below you need to contact a veterinarian as soon as possible. Parvovirus is treatable, but intensive veterinary care is needed to support your dog through the infection. 

Signs of Parvovirus are: 

Your veterinarian can diagnose Parvovirus with a fecal sample and admit your dog into the hospital for treatment. Puppies who do not get veterinary care can die from this disease within a few days due to the significant fluid loss from vomiting and diarrhea. 

Frequently Asked Questions

How much does a Parvo vaccination cost?

Parvovirus vaccination is relatively cheap, usually, the vaccine costs between $10-30. Charities and welfare organizations hold free vaccination drives so you may be able to vaccinate your puppy at no cost. 

Can you give a dog a Parvo shot if they have Parvo?

No, it is not recommended to give a dog a parvo shot if they already have parvo. The parvo vaccine is designed to prevent the disease, not treat an existing infection. If you suspect your dog has parvo, seek immediate veterinary care for proper diagnosis and treatment.

Can my puppy get Parvovirus from a parvovirus vaccination?

No, the vaccination is a modified version of the virus that will not cause Parvovirus disease in your dog. 

Are there any side effects from Parvovirus vaccination?

Some dogs can get a mild swelling over the vaccination site, and be a little sore for a day or so. This usually resolves by itself and is not something to be worried about. Other side effects include vomiting, diarrhea, or anaphylaxis. Contact a veterinarian if you are concerned your dog may be having a vaccine reaction. 

Can I vaccinate my pregnant dog for Parvovirus?

Yes, depending on the brand. Your veterinarian will know which ones are safe and will recommend the proper vaccine.   


In summary, a fully vaccinated dog can get Parvovirus, but this is a very rare occurrence. Vaccinations against Parvovirus have saved thousands of lives, and as veterinarians, we wholeheartedly advise you to vaccinate your dog. Not every vaccine is 100% effective, but by vaccinating your dog, you are giving them the best chance at a healthy life.

Vaccine reactions to Parvovirus are very low, and the vaccine procedure is minimally painful to your dog. The benefits far outweigh the risks. We understand that in the current age of vaccine uncertainty, it’s important for you as a parent to understand the benefits, risks, and process of Parvovirus vaccination to be fully informed.

Our veterinarians at BetterVet have a lifetime of experience in this area and would love to talk through your concerns in a physical or online appointment