To Vaccinate or not to Vaccinate…………..this is the question

Routine vaccinations have been given to our dogs for many years now but it has only been since the 1960s that we have been giving our dogs a regular annual vaccination.

All dogs in the UK are vaccinated against canine distemper, adenovirus, parvovirus, parainfluenza virus and leptospirosis. These vaccinations are combined into a multi-antigen vaccination and given to dogs usually from the age of 6 to 8 weeks with the last vaccination being given at either 10 or 12 weeks of age. This vaccine combination is then repeated annually. Infectious canine tracheobronchitis (‘kennel cough’) is a complex, multifactorial condition caused by a number of possible causing agents including Bordetella. This vaccination is usually administered every 6 months to prevent kennel cough when a dog is going to the kennels.

Any factors such as the animals age, health status, and maturity, the presence of maternally-derived antibodies, the antigenic mass of the vaccine used, and the presence of infection in the environment may affect fixed canine vaccination programs.

Companion animal vaccination guidelines are currently undergoing critical scrutiny by representatives from private practice, industry, and the academia. Despite widespread recommendations for annual revaccination, information available today suggests that current vaccination practices in the UK do not necessarily correspond with the body of knowledge pertaining to duration of immunity derived from licensed vaccines. As a result, companion animal veterinarians should expect significant changes in the current standard of practice pertaining to the administration of vaccines to dogs.

Among the most significant changes anticipated in the future will be the recommendation to discontinue routine administration of annual booster vaccination to adult dogs. The reasons for this are that the incidence of most vaccinated diseases in adult vaccinated dogs ( greater than 1 year of age) is virtually zero. The correlation among vaccination, the development of a ‘positive’ antibody response, and protection from exposure to virulent virus is excellent. Furthermore, protection derived from immunisations sustain for periods as long as 5 or 6 years or more. Further vaccination standards for adult dogs are likely to centre vaccination intervals of 3 years. Annual vaccination boosters are likely to be recommended for those animals considered by the clinician to be at risk of exposure.

Providing effective immunoprophylaxis to the pet dog population does not require that all dogs presented for vaccination be inoculated with each of the antigens for which a vaccine is currently licensed. Factors related to the individual patient, both intrinsic and extrinsic, as well as factors unique to the infectious agent should be taken into consideration when establishing recommendations or when assigning a vaccination protocol to an individual animal.

Some vaccines designated core vaccines, are appropriately recommended for all young dogs. Deciding on these core vaccines should be based on :

1. The severity of the disease

2. Infection is zoonotic and potentially harmful to humans

3. The disease is prevalent and easily transmitted so that it poses a risk to the population of animals at large

As a practicing clinician, I have been approached by owners of dogs over 3years of age and asked if vaccinations are needed annually. In considering all the above problems we can encounter with over vaccinating and vaccinating for diseases that are no longer a problem, I have offered my owners the option of a blood test to see if the previous vaccinations their dogs have had, have actually worked. This process involves a blood sample to measure the antibody levels in the dog to the various diseases they have been vaccinated against.

An interesting phenomenon has emerged…….all the dogs that I have blood tested, have had a more than a sufficient amount of antibody needed to protect the dog, and hence no further vaccinations have been given. These clients will be presenting their dogs again after a year again for blood sampling to see whether we still need to consider vaccinating. This test trial of mine has only been going for 1 year now, but if the antibody levels hold up, we might not need to revaccinate for sometime to come.