Some vaccinated dogs will still develop the cough though this will likely be much less aggravated and should comfortably shrug the virus off within a week or so.
Sometimes very elderly,young or unhealthy dogs will still develop the persistent retching cough and need the necessary veterinary treatment to stop the risk of a secondary chest infection.
If the symptoms do persist and you feel it necessary to visit your vet then when you arrive at the surgery leave the dog in the car so the virus isn’t spread among the other dogs in the waiting room. In most cases the vet will give the dog something to suppress the cough, this reduces further damage to the lungs and allows the body to start the healing process. In some cases, antibiotics will be provided to address the bacterial part of the disease. Unfortunately the virus must be left to be dealt with by the body’s own immune system..