Not surprisingly, “should my dog be vaccinated against flu?” has been a very common question over the past few days. Here’s my take on vaccination of Canadian dogs, with the assumption that the recent H3N2 flu cluster in southwestern Ontario has been contained (something that is likely but is still to be determined).

Who should be vaccinated?

  • Dogs that will be travelling to areas in the US where there is canine flu activity (or more broadly, dogs that travel to the US, since canine flu is present in various regions).
  • Dogs that may have contact with dogs imported from Asia. This includes mainly dogs in rescues and kennels that are actively importing dogs, as well as dogs in households of people thinking about adopting a dog from Asia.
  • Dogs that may have contact with dogs imported (or travelling) from the US. The risk here is lower, but if dogs are coming from US shelters, in particular, it’s not a bad idea to vaccinate the dogs that will have contact with them.

When else might vaccination be useful?

The benefits of vaccination decrease as the likelihood of exposure decreases. There are a few more groups where vaccination could be considered:

  • Dogs at increased risk of exposure. This includes dogs that have frequent contact with lots of other dogs, especially dogs from a wide geographic range, such as those that travel for shows or other similar events.
  • Dogs at increased risk of serious consequences. This includes dogs with pre-existing heart disease or lung disease, potential senior dogs, and brachycephalic breeds (i.e. smushy faced dogs like bulldogs).

What about everyone else?

On one hand, it’s easy to say that the risk of exposure is very low, so vaccination is of very low utility (because it’s true). The tricky part is the fact that you never know when (and it’s probably when, not if) canine flu will revisit Canada. It takes two doses of vaccine given a couple of weeks apart for good vaccine effectiveness, so by the time a problem is identified, dogs in the immediate area may already be exposed before vaccination has time to work.

That’s an inherent problem with emerging diseases.

H3N2 canine flu could pop up in any given city tomorrow, but it also might not happen for years. At the moment, it’s hard to say that vaccination is broadly indicated in Canadian dogs, but if people are particularly worried about flu, it’s a safe vaccine and there’s no reason not to get it.

What about my dog, Merlin?

He’s pretty low risk. We live in the country and he doesn’t see other dogs at home. However, he goes into work with Heather regularly and mixes with a few other dogs there. It’s a fairly small population, but those dogs presumably regularly meet other dogs (who meet other dogs…), so if flu emerged in this area, he’d be at some degree risk. At the moment, I don’t have a plan to vaccine him against flu. (Leptospirosis is a different story. He’s getting that booster tonight.)

More information about canine influenza can be found here.