Petlife heart logo


Would you visit the veterinarian more frequently if:

View Results

Loading ... Loading ...


Lions Foundation of Canada Dog Guides and its founding program, Canine Vision Canada, was established in 1983. It’s the largest school of its kind in Canada with its training school in Oakville and breeding facility in Breslau.


An Argument for Splitting Up Vaccines in Small Dogs

A study, namely ‘Adverse events diagnosed within three days of vaccine administration in dogs’ by GE Moore [2005], has indicated that a greater percentage of small dogs experience vaccine-associated adverse events (VAAEs).

Evidently then, injection of multiple vaccines at one time is likelier to produce vaccine-associated adverse events in small dogs.

Risk Factors

The study indicated that the risk of a vaccine-associated adverse event (VAAE) was inversely related to a dog’s weight. Genetics of the animal, for example small breed dogs or families of dogs, can also play a role and components other than the primary antigen may contribute to adverse events as well. Still, low weight as a risk factor carries more weight, so to speak:

‘When multiple vaccines are simultaneously administered to a dog, the ratio of volume received per kilogram of body weight per patient also varies. The importance of this volume-to-weight ratio in relation to adverse event risk was evident in this study by the increase in VAAE rates as the number of simultaneously administered vaccine doses increased, even when adjusted for weight.’


Splitting up vaccines, so a dog does not get more than one vaccine per visit, can be done. A veterinarian can split up and give vaccines on different days, for example, two weeks apart. It may not be convenient for the owner or fun for the dog, but if it reduces the risk of a vaccine-associated adverse event it is worth it.


Even though vaccines are tested for efficacy and safety, no vaccine is completely effective or absolutely reaction free. However, it is also important to realize that evidence of vaccine-associated adverse events (VAAEs) does not mean vaccines are not safe; instead it shows a small risk of adverse events associated with certain dog factors or vaccines.

Conclusions and Clinical Relevance of the Study

The conclusions of the study were that young adult small-breed neutered dogs that received multiple vaccines per visit were at greatest risk of a vaccine-associated adverse event (VAAE) within 72 hours after vaccination.

These findings are important as they should be considered in risk assessment and risk communication with dog owners prior to vaccination.

previous arrow
next arrow
Print Friendly, PDF & Email