SAN JOSE (CBS SF) — Hospital officials at Kaiser Permanente San Jose Medical Center confirmed Saturday evening that 43 emergency room staffers have tested positive for COVID-19 in the last week.

In a statement to KPIX 5, Irene Chavez, senior vice president and area manager, Kaiser Permanente San Jose Medical Center, said the outbreak began on Dec. 27.

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“We have determined that 43 staff members at the Kaiser Permanente San Jose Emergency Department have tested positive for COVID-19 between Dec. 27 and Jan. 1,” Chavez said. “We will ensure that every affected staff member receives the care and support they need. Using our infection prevention protocols, we are investigating the outbreak and using contact tracing to personally notify and test any staff or patients who were exposed during this time period based on CDC and public health guidelines.”

“We are also moving quickly to test all emergency department employees and physicians for COVID-19,” she continued. “Employees confirmed to have COVID-19 or suspected of having COVID-19 due to symptoms will not come to work.”

The hospital’s emergency department has also undergone deep cleaning and the Medical Center remains open.

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Officials said that one of the infected staffers did “appear briefly in the emergency department on Dec. 25th wearing an air-powered costume.”

“Any exposure, if it occurred, would have been completely innocent, and quite accidental, as the individual had no COVID symptoms and only sought to lift the spirits of those around them during what is a very stressful time,” the hospital said in the statement.

The outbreak comes as Santa Clara County hospitals are being pushed to the brink by a surge in COVID-19 cases. On Saturday, county health officials reported there were 1,784 new positive cases with 37 deaths and 108 hospitalizations. The county has had a 7-day rolling average of nearly 1,000 positive test results each day.

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There were just 10 ICU beds available in the county of over 2 million residents as of Saturday.