YVR does have sterile transit for USA-International pax. YVR is a gateway to Asia, and there are a large number of pax who do connect from the USA to Asian flights via YVR.

I am not sure if recent Canadian or American regulations have restricted the use of the sterile facilities, but they are there nonetheless.

IIRC, the new terminal at Toronto's Pearson International is also being built to allow sterile connections.