Quebec delays vaccine mandate for health-care workers, fearing staffing crisis
cbc.ca
cbc.ca
Less to do with staffing levels and more to do with voting blocks I’d presume.
Remember the executive order was for OSHA to study this and then come up with a ruling, and that hasn't even happened yet, let alone the inevitable court challenges once OSHA comes up with a new policy.
So action now means that the employer is just acting unilaterally, without any actual OSHA requirements, trying to amend a union contract - instead of waiting for the OSHA ruling to come out. That's not a particularly strong position to be in. If you are in a rush, then reach out to the union and ask them what it would take to agree to a modification of the contract. Unions will bargain with you if you bother bargaining with them instead of trying to impose mandates.
Now unions only cover a small share of employment, but they tend to be bigger in the healthcare sector, and in the current environment workers have a lot of options.