Hamilton Health Sciences has confirmed a nurse who works at McMaster Children's Hospital has tested positive for COVID-19.

"We are working with Hamilton Public Health to identify and inform individuals that may be associated with this case ... this is occurring now," Lillian Badzioch, spokesperson for HHS, told CBC News Saturday morning.

"Those who met exposure criteria with the nurse were directed to go into self-isolation at home immediately. ... the area where the nurse provided care has also been thoroughly cleaned and disinfected."

Badzioch said Hamilton Public Health notified HHS on Friday, but would not specify the time of day.

"The nurse did the right thing by contacting HHS Employee Health Services as soon as they started experiencing symptoms and did not return to work," she said.

There are few details about the case.

It's unclear what unit the nurse worked in, how many staff and patients might be affected, how severe the nurses' symptoms are and how they contracted the virus.

"The entire situation is very concerning," Badzioch said in a phone interview with CBC News.

This is the second nurse working in a Hamilton hospital to test positive for the novel coronavirus.

The previous nurse worked at the Charlton campus of St. Joseph's Healthcare Hamilton and provided dialysis care at Hamilton General Hospital.

There are 52 confirmed cases of COVID-19 in Hamilton as of Saturday at noon.