Frank the Tank
The Godfather
The US struck deals, funded production, etc. with many companies to try and hedge their bets to get a vaccine ASAP to try and get things back to normal ASAP. Maybe Canada felt that since they didn't get hit very hard in the spring that they could wait? Not a wise idea if that was the case IMO. Given the population size and wealth of the country there really is no good excuse for basically waiting around for apple cores like Joe Dirt.
It's more complex than that. Canada also struck deals with at least 7 companies. This article gets into the nuance of the situation:
Will Canada lag behind on coronavirus vaccines? It’s complicated, experts say