Why do vaccinated dogs still get kennel cough?

The AVMA describes three routes: close contact such as licking and nuzzling, breathing in droplets from an infected dog's cough or sneeze, and touching contaminated things like toys, bedding, water bowls and even people's hands. The risk is highest when dogs spend long periods in close contact, which is why the AVMA names kennels, shelters and daycare facilities as the settings of particular risk. The Merck Veterinary Manual adds that stress and extremes of ventilation, temperature and humidity make dogs more susceptible.

Timing is what makes it hard to stop. According to the AVMA, most dogs with CIRDC are contagious before they start showing signs, and some of the organisms can survive in the environment for weeks. The AKC puts the incubation period anywhere from 2 to 14 days. A dog can pass a careful morning check looking perfectly well while already shedding infection, and no daycare can screen that out at the door. Vaccination and keeping sick dogs home are the two tools that work.

Most cases are mild. The AVMA says dogs with mild CIRDC usually recover fully within 7 to 10 days, and the classic sign is a frequent, honking cough that comes on suddenly and gets worse with exercise. Not every dog coughs, though: sneezing and a runny nose or eyes are common signs too. Puppies, and older dogs with other health problems, are at greater risk of severe disease, so watch them more closely after any exposure.

Know the signs that change the plan. The AVMA lists lethargy, decreased appetite, fever, a productive cough and rapid or labored breathing as signs that bacteria may have reached the lungs, and says they need immediate veterinary attention. If you suspect kennel cough, call your clinic before you go in, so the staff can see your dog without exposing other patients. Keep a coughing dog home from daycare, tell us, and see our companion answer on when to return.