Is the Flu Vaccine a Smart Choice For Your Dog?

Photo Credit: Flicker CC, Maja Dumat, tennisballNews articles about the expanding canine flu “epidemic” are popping up everywhere, and they seem intent on creating fear and worry. Rest assured, there is no need for panic. The better response is to learn about this disease and then consider whether or not vaccine protection makes sense for your dog.

What exactly is canine flu?

A virus known as H3N2 is the cause of the recent spate of canine flu (influenza) cases. The first dogs documented to have this virus were reported in 2015. To date, cases have been documented in most states within the United States. Much like human flu viruses, canine flu is quite contagious, spread primarily via respiratory secretions such as the type aerosolized through coughing and sneezing. The H3N2 virus remains active and infectious within the environment (kennel surfaces, bedding, toys, food and water bowls, etc.) for 12 to 24 hours. The virus is readily killed with soap and water. While the canine influenza virus can infect cats, it is not transmissible to people.


Because H3N2 is a brand new virus, dogs don’t carry any inherent immunity. This means that, once exposed, pretty much all dogs will develop the infection. Approximately 80 percent of those infected develop symptoms (approximately 20 percent remain symptom-free), and they occur within two to five days following exposure. Most infected dogs display the milder form of the disease with a cough that persists for two to three weeks. More severe symptoms can develop such as lethargy, decreased appetite, nasal discharge, and fever.


A definitive diagnosis of H3N2 infection is made via laboratory testing performed on swab samples obtained from the nose or throat. Other testing such as chest x-rays and blood tests may be recommended to rule out other causes of coughing.


Treatment for canine influenza consists of supportive care, antibiotics for secondary bacterial infections, and cough suppressant therapy. While most dogs recover within approximately two weeks, they may remain contagious to other dogs for up to four weeks and isolation from other dogs during this time is recommended.

A small percentage of dogs infected with the H3N2 virus go on to develop pneumonia for which hospitalization may be required. A handful of deaths associated with canine influenza have been reported.

The flu vaccination

A vaccine that provides protection against H3N2 infection is available through your veterinarian. It’s not a perfect vaccination in that it doesn’t always prevent infection, but it should lessen the severity and duration of symptoms. The initial vaccination series involves two injections given two weeks apart. The vaccine is then repeated annually.

Is your dog a good candidate for the flu vaccination? To figure this out, begin by asking your veterinarian if cases of canine influenza have been documented in your locale. If so, and your dog frequents venues where lots of dogs congregate (dog park, grooming parlor, doggie day care facility, competition event, boarding facility), the vaccine makes good sense, assuming that your dog has tolerated vaccinations well in the past. If your dog is a homebody with very limited exposure to other dogs, there is likely no need to consider vaccinating.

The canine flu vaccine should be considered for dogs who are elderly, infirmed or have underlying respiratory tract disease. These are dogs who might not tolerate a two to three week spate of significant coughing.

It is important to talk with your veterinarian and formulate a plan that makes the most sense for your dog. Keep in mind that vaccinations are no different than any medical procedure. They should not be administered without individualized discussion with your veterinarian and consideration of the potential risks and benefits.

Has your dog been vaccinated against canine influenza? If so or if not, what is your reasoning?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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Please visit to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at,, local bookstores, and your favorite online book seller.

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One Comment on “Is the Flu Vaccine a Smart Choice For Your Dog?

  1. My Detector dog has had his first flu shot w booster to come… but he lives at a commercial boarding kennel.
    My personal dogs are homebodies so they will not receive the vax

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