I have been trying to figure out how I get it and my brother the dentist, hasn't. So I called him. He bought two hepa filtration devices for the rooms he sees patients in that draw the air away from him.
All of his employees are vaccinated, not necessarily by choice.
The furnace is old and could not handle a thick hepa filter, so, he closed off the cold air returns.
He wears an N95 and surgical mask throughout the workday. And they clean surfaces.
I live in a rural area where we have 59.5% vaccination rate for people over age 12. Those in this county who are not vaccinated in general are unlikely to vaccinate unless disaster strikes their family.