Through OSHA (Occupational Safety and Health Administration). I.E. viewing unvaxxed employees as making the workplace unsafe. Businesses that don't comply will be fined.
Patriots should have fought hard against OSHA in the first place, because the whole concept violates the Constitution directly.
"A senior administration official estimated that this new OSHA requirement will cover about 80 million workers and businesses that do not comply with the agency’s rule can face substantial fees"
DoD Law of War details how the occupying power must care for the health of the citizens and can also restrict movement.
Depends on who you think is in control. It also deals with how a nation deals with an occupying power.