VICTORIA -- A COVID-19 outbreak affecting five staff members at a Nanaimo hospital may have been brought into the health-care facility from the Lower Mainland.

That’s according to Island Health’s chief medical health officer Dr. Richard Stanwick.

Vancouver Island’s top doctor told CFAX 1070 on Thursday that public health investigators “have a pretty good idea” who the source of the outbreak was at Nanaimo Regional General Hospital.

Stanwick said the virus was likely community acquired and brought into the hospital, but not by a patient.

“There was somebody who possibly may have come from the Lower Mainland who was the source of the COVID,” Stanwick said.

The health officer said more than half of Vancouver Island’s COVID-19 cases are related to travel to or from the mainland.

“People who are travelling to the Lower Mainland, please only do it for essential travel,” Stanwick pleaded. “This is not a time to basically take a holiday in Vancouver."

Island Health has tested every patient in the affected transitional care unit and most staff members who spent more than 15 minutes in the unit, Stanwick said.

So far, all additional tests have come back negative, he added.

Some of those who tested positive were included in Tuesday’s announcement of seven new cases in Island Health, Stanwick said.

Island Health declared a COVID-19 outbreak at the hospital Wednesday night. It’s the first outbreak declared in the Island Health region since the pandemic began, and one of only a handful of outbreaks outside of the Lower Mainland.

The hospital unit is currently closed to admissions and visitors while enhanced cleaning and contact tracing are underway.

The emergency department at NRGH remains open, and no other areas of the hospital are affected, Island Health said.