Windsor Regional Hospital now has COVID-19 outbreaks on four units at both of its campuses.
So far, 19 patients have tested positive for the virus on 7 North and 6 North at the Met Campus and 7 East and 6 West at Ouellette.
Most are not suffering any symptoms, and the majority of transmissions have been among those sharing a room.
The hospital urges those who have not been vaccinated against COVID-19 not to visit units under outbreak.
It also recommends anyone who was recently to isolate for ten days and watch for symptoms.