By Carrie Hyde, The Spaw Pet Life Coach | December 9, 2021

The canine influenza vaccine is being recommended by more and more veterinarians as an annual shot given to all dogs. Considering how new these flu viruses are to the canine community, most owners know very little about the disease and even less about the vaccines they are being told to give their dog.

In this article, we’ll look at what exactly canine influenza is, how worried about the disease you should be, and if the vaccines are safe and worth giving. So next time you go to the vet, you can feel confident in your decision to add—or not—this new shot to your dog’s regimen.

What Is Canine Influenza?

According to the CDC, canine influenza is a contagious respiratory disease caused by two different type A influenza viruses.

The first virus, influenza H3N8, has existed in horses for over 40 years. In 2004, cases of H3N8 were reported in a greyhound racing kennel in Florida. Over the course of a year, the virus began to spread across the United States. Today, outbreaks of this illness have been reported in 46 states and Canada.

The second type of virus known to cause this disease in dogs is H3N2 influenza. This type originated in birds and spread to dogs in South Korea sometime in 2007. The disease was largely isolated to Eastern Asia until it finally made its way to the United States in 2015.

How Dangerous is Canine Influenza?

Much like the human flu, dogs suffering from canine influenza will show upper respiratory symptoms such as:

• Cough
• Runny nose
• Fever
• Eye discharge
• Lethargy
• Reduced appetite

These symptoms are present in about 80% of dogs who become infected. The other 20% will show no signs at all.

If symptoms do occur, they tend to last less than 3 weeks. If a dog has a weakened immune system, there is a chance that a secondary bacterial infection can take hold which can greatly delay recovery.

Death rates from the H3N8 virus range from 1% to 5% depending on the severity of the outbreak. Though, there is a high chance this number is inflated, as most vets will diagnose canine flu without performing the costly test needed to confirm the diagnosis. In Asia, death rates from the H3N2 virus have been reported as high as 25%. However, the virus strain in the US is much weaker and mortality rates here are closer to 0.5%.

While both forms of canine influenza have higher reported mortality rates than human influenza A viruses, the odds of your dog being exposed are much lower.

While both viruses have now been found in most states in the US, outbreaks tend to be isolated and individual cases are relatively uncommon.

Canine Influenza Vaccines

There are currently canine influenza vaccines available for each type of virus as well as a combo that is meant to protect against both.

These vaccines are often offered to dogs in states where the virus has been previously detected. According to the AVMA, this shot is considered a “lifestyle” vaccine, which means the dog’s habits, health, and risk should all be taken into consideration before the vaccine is given.

When a dog receives their first flu vaccine, they must get a follow-up booster two weeks later to boost its effectiveness. After that, the vaccine is to be given annually. If an annual dose is missed, your vet might recommend restarting with a booster round the next time they need the shot. So, unfortunately, choosing to give the vaccine means committing to doing it yearly even if your dog’s risk factors and lifestyle change.

How Effective Is the Vaccine?

Because influenza A viruses tend to mutate rapidly, creating a vaccine that is 100% effective is impossible. In humans, flu vaccines are changed each year to protect against the strain most likely to cause issues over the winter months. This gives the human flu shot an effectiveness rating of around 40%.

With the dog influenza vaccine, unfortunately, this type of yearly update does not happen. So, its efficacy tends to be much lower. Whether your dog gets the combo vaccine or one specific to H2N3 or H2N8 will also influence how well protected your dog is.

Side Effects of the Vaccine

Similar to the human influenza vaccine, dogs can suffer side effects from this shot. These tend to be minor and are mostly related to activation of the immune system, which is the intended consequence of the vaccine.

Common side effects include:

• Fever
• Fatigue
• Vomiting
• Diarrhea
• Pain at the site of the injection

Less common side effects related to allergic reactions have been documented and include:

• Swelling of the face
• Respiratory distress
• Anaphylaxis

Which Dogs Are Most at Risk of Getting Canine Influenza?

Dogs most likely to be exposed to these viruses are those who frequently come into contact with other dogs. This includes dogs who:

• Are boarded frequently
• Travel for shows or sports
• Spend ample time at the dog park
• Go to doggy daycare

Dogs with underlying health conditions, those who are immunocompromised, and brachycephalic dogs are the ones most likely to get severely ill from canine influenza. Dogs that are relatively healthy are not likely to get severely ill even if they haven’t been vaccinated.

More Factors to Consider

Many owners don’t think about giving the canine influenza vaccine until they are about to board their dog. Unfortunately, giving the shot immediately before boarding does nothing to protect them. It takes at least two weeks for your dog to develop antibodies after the booster dose. That means you would need to start the vaccine process at least a month before boarding if your dog were to benefit from it at all.

Currently, the most popular canine influenza vaccine options are killed virus types. But there are live-attenuated vaccinations in the works. If your dog is given a live virus vaccine they risk shedding it to other dogs, especially those with immune deficiency. This is another reason why you should not get your dog vaccinated right before boarding them.

If your dog boards frequently and is at high risk for severe illness, then it may be worth getting them vaccinated. But for the occasional border, the vaccine tends to be much more hassle than it’s worth.

Bottom Line: Should Your Dog Get the Canine Influenza Vaccine?

For the average dog, the risk of getting canine influenza is low. And the odds of them getting severely ill or dying is even lower.

If your dog doesn’t have underlying health conditions, then you can protect them from the dog flu by ensuring they are getting proper nutrition, giving them plenty of exercise, keeping their stress levels low, and reducing their exposure to toxins. Because the canine influenza vaccines have such low efficacy, doing these things is likely to protect your dog more than giving them the shot.

On top of taking these steps, you should always be careful of where you board your dog. A quality boarding facility that works to reduce the stress of the dogs in their care, maintains strict hygiene standards, and limits their capacity isn’t going to be a place where canine influenza readily spreads.

By being picky about where your dog boards and keeping them healthy, you can greatly reduce their risk of getting the dog flu without paying for a pricey and often unnecessary vaccine.

By Carrie Hyde, The Spaw Pet Life Coach | December 9, 2021

Written for The Spaw by Sara Seitz, Professional Freelance Writer and Novelist with Pen and Post

Carrie Hyde is the founder, owner, and Pet Life Coach of The Spaw in Tustin, CA. Carrie’s extensive experience and understanding of pet nutrition and coaching enabled her to create The Spawdcast, a podcast dedicated to educating pet parents and pet industry professionals on ALL the options available to their pet. Her mission is to open pet-owner’s eyes to the questions they may not even know to ask, to shine light on the many myths that have been part of pet care for decades and to offer whole solutions for their pets. Carrie Hyde is a certified pet nutritionists with the goal of helping pet parents & pet professionals with a new understanding about how to care for pets in a “whole and natural” way.