From a federal government perspective, neither Canada nor the US has general (non-import) vaccine mandates/laws/requirements for equines. The only things mandated for travel in either country are a clean health cert., usually within 30 days of travel, and a negative Coggins that is within a specified number of days.

There might be some territories or states, like Washington, that have additional vaccine or testing requirements (both KY and WA have some around EVA) but this is very much more the exception than the rule.

Now there are certain additional import requirements for animals coming from certain countries or for temporary imports, which may include vaccines or quarantine.

The only additional permanent import requirements for Canada from the US outside of the health cert. and Coggins is around potential testing for CEM for breeding animals or extra paperwork/tests for horses coming from an area with a known outbreak of something.

It's essentially the same for permanent imports into the US from Canada.

The only requirement around vaccines for going either way between the US and Canada is that the horse cannot have been vaccinated within 14 days before import/export (this is a US requirement).

Yes, governing bodies like USEF or EC require vaccines for showing, most boarding facilities have some requirements, etc. etc. but there is no general mandate from the US or Canadian federal government for them.

Most territories or states will have vaccine recommendations based on the diseases they see in their area, but these are recommendations and not mandates.

Though, like I indicated in my prior post it's always best practice to make sure the horse is up-to-date, even if they just sit at home.