BOSTON (CBS) – A coronavirus cluster has been discovered at Brigham and Women’s Hospital involving seven patients and 11 staff members. The hospital said on Thursday that the cluster is connected to two inpatient units on the 14th and 16th floors where positive tests were reported.

“The concern is that they’re not sure if this came in with a patient, or came in with an employee, or a visitor,” said Trish Powers, a nurse at the hospital.

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The hospital said the cluster was detected by the infection control team.

“Through an intensive tracing process, our experts are working closely with all involved to ensure that others who may have been exposed are identified and tested,” the hospital said in a statement.

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“The Brigham is committed to creating and maintaining a safe care environment by testing all patients admitted to the hospital, requiring staff to attest to their health daily before working, requiring all staff, patients and visitors to wear hospital-issued masks while on campus, insisting on frequent hand hygiene, frequently cleaning the environment, and enforcing appropriate physical distancing.”

Powers said there are potentially a lot of people who may have been exposed, including nursing staff, doctors, residents, cleaning crews and food service workers. The hospital has tested more than 300 people so far.

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Nurses said this could not have come at a worse time as health care providers are preparing for a second surge of the virus. They are asking anyone who may have been a patient or visitor on Unit 14CD or 16A in the last few weeks to get tested.