TORONTO -- The Hospital for Sick Children in Toronto has declared a COVID-19 outbreak.

SickKids said in a statement earlier this week that a patient had tested positive for the novel coronavirus. Since then, his parents and one health-care worker have contracted the virus, the hospital said in a statement.

The hospital says one other patient has also tested positive for the virus, but is not connected to the first patient.

"The ensuing headlines of an outbreak at SickKids will no doubt be alarming to many,” the hospital’s CEO and President Ronald Cohn said in a statement. “But it is important to know that the Toronto Public Health definition of outbreak has a very low threshold given that we are all learning about this organism."

"There is no higher priority for us than your safety, and that of our patients and families. As soon as we received the positive test result for our staff member, many teams at SickKids came together to mobilize a response and implement enhanced infection prevention and control measures."

The patient’s parents and a member of the care team have also tested positive. Everyone who has been exposed or suspected to have been exposed has been notified. All patients on the affected unit have tested negative for COVID-19. Staff on the unit continue to be tested. — SickKids_TheHospital (@SickKidsNews) April 28, 2020

"These are challenging times for all of us, even more so for our colleagues, who will be working under extraordinary circumstances."

SickKids has previously restricted visitors to one adult caregiver per patient in an attempt to limit COVID-19 and has begun screening patients and visitors for symptoms upon arrival.