The staff member was in contact with Ford on Monday, and was tested on Tuesday after learning they had been at risk of exposure, according to Ivana Yelich, spokesperson for the premier.
That staff member received a positive test result on Tuesday evening.
Ford left the Ontario legislature to be tested as soon as he learned the staffer was at risk of exposure, Yelich said in a statement. The premier has received a negative test result.
“While his test results have returned negative, the premier will follow all public health advice for close contacts of positive cases, including isolating,” she said.
Members of Ford’s office staff, who were close contacts of the staff member who tested positive, will also go into isolation.
“We are seeking additional guidance from Toronto Public Health on all precautions that the premier and isolating staff must follow,” Yelich added.
“The premier will continue leading this government’s response to the COVID-19 pandemic while in isolation, including briefings with officials and communicating with the public.”