Bordetella is the most common cause of tracheobronchitis (kennel cough) in dogs. It is a bacterial illness that is most common among dogs that congregate at things like shows, kennels or other places frequented by large numbers of dogs at once. It does not appear that this bacterin gives a full year of immunity in many instances. For dogs that are often exposed to situations in which the infection is likely probably should be vaccinated twice a year. There are intra-nasal as well as subcutaneous bacterins available for this disease. The intra-nasal bacterin confers immunity more quickly but the injectable version may last longer.