St. Joseph’s Hospital staff tested four patients for chicken pox this week after contact with an infected nurse.

The nurse contracted the virus on June 28, and so far is the only one who has it. But the hospital has backtracked through the areas the nurse worked, and confirmed that all but four patients were immune, said spokesperson Maria Hayes.

St. Joe’s reported late Friday that the patients were immune.

The nurse was in the King Street East Urgent Care Centre and the renal transplant and urology departments.