Breathe, relax, and vaccinate for CIRDC

Why do we vaccinate? Yes, to prevent disease, but which characteristics determine if a vaccine should be made or not? In general, we vaccinate against diseases that are either common or deadly. Sometimes, we have a highly contagious, common disease with an elevated rate of death. Then, we have the experience of 2020.

Luckily for dogdom, no pandemic for them is occurring. Back in the mid-1700’s distemper arose, and there was a canine pandemic. So terrible was this that in 1763, history documented the death of 900 dogs in the streets of Madrid on a single day. Today, vaccinating against canine distemper remains a core antigen for every dog in the world1,2.

For people and pets, a pandemic alone does not determine the need for vaccines. The Bordetella genus generates significant and common diseases. Human vaccination against whooping cough protects against Bordetella pertussis, and the canine vaccine for “kennel cough” protects against Bordetella bronchiseptica3

As the term “kennel cough” has evolved to Infectious Tracheobronchitis (ITB) and now Canine Infectious Respiratory Disease Complex (CIRDC), additional pathogens have been recognized as generating disease in dogs. Beyond canine distemper and Bordetella bronchiseptica, a relatively new agent of canine influenza emerged1.

The story behind canine influenza is a tale of two strains: H3N8 and H3N2. Both influenza strains can cause severe lower respiratory disease in dogs, but that is where the similarities end.

In 2004, a group of racing greyhounds fell sick, and many died of a mysterious virus. The racetrack housed greyhounds and racehorses in proximity. Later, researchers identified this pathogen as a H3N8 equine influenza viral variant. Before this, horses have been dealing with H3N8 for more than forty years. Having established itself as a separate virus within dogs, this influenza strain remains a threat today4.

In 2015, the city of Chicago put avian-origin H3N2 on the map. Dogs across the city were developing pneumonia, and some dying. Even with quarantines in place, the virus kept spreading. It wasn’t until later we found out that our quarantine recommendation of 14 days insufficient. Unlike H3N8, H3N2 continues to be shed for a long time, even out to 21 days1,5.

Remember, vaccines address pathogens, either common or deadly. Bordetella is the former, and influenza, the latter. Their risk assessment, however, remains nearly identical. These respiratory pathogens transfer readily between dogs through direct, aerosol, and limited fomite transmission. So why is it that less than 50% of dogs given Bordetella vaccine get an influenza vaccine?5

We love dogs for their bravery, timidity, joyfulness, sadness, empathy, and socialness. As dogs express this last characteristic within their own species at dog parks, local communities, shows, backyard fences, boarding, grooming, and more, we must protect them against diseases, common or deadly. Consider educating and recommending the bivalent influenza vaccine to many pet owners whose dogs are already receiving Bordetella vaccines1.

Authors: Christopher Lee, DVM, MPH, DACVPM and Debra Olbrich, DVM, MS


  1. AAHA. (2017). Canine vaccination GUIDELINES (2017) AAHA. Retrieved May 25, 2021, from
  2. Blancou J. Dog distemper: imported into Europe from South America? Hist Med Vet. 2004;29(2):35-41. PMID: 15376360.
  3. CDC. (2019, August 02). Vaccine (shot) for whooping cough (pertussis). Retrieved May 25, 2021, from
  4. Ford, R. (2019, October 22). Kennel cough revisited. Retrieved May 25, 2021, from
  5. Cornell University College of Veterinary Medicine Animal Health Diagnostic Center, “Canine Influenza H3N2 Updates,” accessed September 30, 2019, vet.cornell. edu/animal-health-diagnostic-center/ veterinary-support/disease-information/ canine-influenza-h3n2-updates.


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