A hospital in B.C.'s Lower Mainland has stopped admitting new patients as it works to address an ongoing COVID-19 outbreak, but the emergency department remains open.

Delta Hospital first announced the outbreak in one of its units on Sept. 16. At the time, admissions to the particular medicine unit were halted after two patients tested positive. No other units were impacted, however.  

But on Monday, Fraser Health said in a news release that no patients will be admitted to the hospital as a whole, "in order to further protect them from the risk of transmission of COVID-19."

"If a patient needs admission to hospital for further care, they will be transported to an appropriate hospital within the Fraser Health network," the health authority's advisory says.

Fraser Health later confirmed in an afternoon teleconference that 18 patients at the hospital have tested positive for the disease since the outbreak was declared. As well, 17 staff members have gotten COVID-19, but some of those were community infections not connected to work at the hospital.

Of those, seven people have died. All of those people were older patients on the second floor medical unit where the outbreak was originally reported.

"It has been a very challenging outbreak," Dr. Bonnie Henry during her COVID-19 briefing Monday, saying a "number of factors" led to the spread of the disease at the hospital.

"Like often happens it’s unrecognized cases that spread that cause the biggest challenge in our health-care system."

Fraser Health said Monday that Delta Hospital's emergency department is still open for "urgent and emergent" care and all scheduled surgeries will continue. However, some patients are being transferred to other hospitals.

"Enhanced infection prevention and control measures were put in place at the onset of the outbreak and continue to be in place," Fraser Health's notice says.

"All appropriate staff, medical staff and patients are being tested, and contact tracing is being carried out to prevent further transmission."