There has been a lot of information circulating online recently regarding vaccination protocols in dogs. Amongst the confusion, one thing needs to be made clear, and that is that a vaccination against the respiratory disease known as kennel cough, or infectious canine cough, produces no long lasting immunity beyond about a 12 month period. This is why your dog still needs to visit the vet every 12 months for some form of vaccination. But did you know there is more to it than that? Not all kennel cough vaccines are created equal. Below we will compare intranasal versus injectable kennel cough vaccines, and explain why at Carnarvon Vet Hospital we have opted to use only the latest intranasal vaccines to keep our client's pets as healthy as possible.
Firstly, it is important to note that a vaccination against kennel cough is not always a 100% guarantee that your dog will not contract the disease. There are three main pathogens of infectious canine cough, and these are included in most kennel cough vaccines:
- Bordatella Bronchiseptica (bacteria)
- Canine Parainfluenza (virus)
- Canine Adenovirus type 2 (virus)
But there are also other viruses which can cause respiratory infections, such as herpesviruses, reoviruses and mycoplasma infections. In addition, as with most respiratory viruses, like the human cold and flu, the viruses themselves are always changing and mutating, so an effective vaccine one year may not be as effective the next.
However, a dog vaccinated against kennel cough with the proper vaccine has a drastically lower risk of contracting the disease than an unvaccinated dog, and a marked reduction in symptom intensity and duration if they do.
But how can you increase those odds in your favour and make sure your dog is being vaccinated with the most effective vaccine?
To understand whether intranasal or injectable vaccines work better, we need to look at how some of the common agents of kennel cough infect your dog.
Unlike systemic diseases like parvovirus, the common kennel cough pathogens do not produce a system-wide infection, but only infect the respiratory cells (lining the nasal cavity and windpipe) upon direct contact. Whilst parvovirus travels through the blood stream, the kennel cough viruses do not. Therefore the injectable version of the kennel cough vaccine, that is absorbed through the skin and then into the blood stream, does not stop the kennel cough pathogens from infecting their target tissue.
A better approach, and one utilised by the intransal kennel cough vaccines, is to stimulate local immunity in the respiratory tract itself, and thereby try to prevent the kennel cough pathogens from taking hold in the target tissue in the first place.
One of the ways Boehringer-Ingelheim’s Bronchishield III intranasal vaccine helps prevent the bordatella bacteria from taking hold in the respiratory tract is by competitively excluding the virulent strain, with its own non-virulent strain. It’s a bit like using probiotic good bacteria to stop bad bacteria taking hold in the gut. This occurs within 24 hours of vaccination with the intranasal vaccine.
In an unvaccinated dog, or a dog vaccinated with an injectable only vaccine, this is what may initially happen when your pet comes into contact with kennel cough organisms:
Compared with below, how the intranasal type of vaccine colonises the respiratory tract, and competitively excludes pathogenic kennel cough organisms:
The second way that the intranasal vaccine provides the best protection against infection and disease is by stimulating immune sytem IgA compounds from the respiratory tract itself, which latch onto the kennel cough pathogens as they try to invade your dog’s respiratory tract at the outset.
The third way intranasal vaccines protect against kennel cough is the same as the only method the injectable vaccines use, and that is via systemic IgG immune compounds that come from the blood stream. This method is only able to reduce clinical signs of infection, since their release is only triggered after the kennel cough pathogens have bound to the respiratory tract lining. So since this is the injectable vaccines single and only method of combatting the kennel cough pathogens, you can see why they do not prevent infection, they only reduce the clinical signs once infection occurs.
So you can see from the above diagrams that the intranasal vaccine has the ability to prevent the kennel cough infection from occurring, whilst the injectable version does not. This fact is represented in what we see in practice with the following statistics:
There are a number of other benefits of using an intranasal kennel cough vaccine over an injectable version, including:
- Only one intranasal vaccine needs to be given for adequate immunity (the injectable version needs two boosters)
- The intranasal version is not affected by maternal antibodies from a puppy’s mother, whereas the injectable version can be.
- Pets vaccinated with the intranasal vaccine have less shedding of the kennel cough virus, after being challenged with the virulent virus, than dogs given the injectable form (crucial if you have other dogs in the same house or in a kennel situation)
- The intranasal vaccine has a more rapid onset of immunity than the injectable version.
What this all means
Now that you know the difference between the two main types of kennel cough vaccine (intranasal and injectable) you will be able to ask your vet which one they use. You may want to request that your dog receives an intranasal kennel cough vaccine for the reasons highlighted above, to give your pet the best chance of protection against contracting the dreadful canine kennel cough.
Carnarvon Vet Hospital uses and recommends Bronchishield III intranasal vaccines in the prevention of kennel cough, for the wellbeing of our patients. We are not paid, sponsored or endorsed by the manufacturer to make these recommendations.
If you live in the Gascoyne region of Western Australia, and have a pet in need of vaccination, be sure to contact us on (08) 9941 1886 or visit us at 318 Robinson St, East Carnarvon.
Article written by Dr Shanon Donovan
Dr Shanon is the practice owner and a veterinarian at Carnarvon Vet Hospital.
Disclaimer: Information in this article is offered as a helpful public service. Although this article is written by professional veterinarians, the accuracy of its content cannot be guaranteed, and it is therefore not intended as medical counsel or to take the place of your own veterinarian's professional guidance. No guarantee is given that the information provided herein is correct, complete or up-to-date. Please consult your vet before administering any treatment(s) to your pet.