The hospital is investigating the outbreak and told KGO-TV in an email that the spread "may" have been connected to an "air-powered costume."
Officials confirmed an employee appeared briefly in the emergency department wearing an inflatable costume on Christmas Day.
"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," Chavez said. "If anything, this should serve as a very real reminder that the virus is widespread, and often without symptoms, and we must all be vigilant."
The emergency staff was the first to receive the COVID-19 vaccine less than 10 days ago and the hospital said they "would not be expected to have reached immunity when this exposure occurred. It is important not only for everyone to get vaccinated, but to receive the required two doses of vaccine to be protected."
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The hospital says the emergency department is still open and safe to receive care and all areas of the department are undergoing deep cleaning. An ongoing investigation and contact tracing among staff and patients are underway.
"Obviously, we will no longer allow air-powered costumes at our facilities," Chavez told KGO. "At the same time, we are taking steps to reinforce safety precautions among staff, including physical distancing and no gathering in break rooms, no sharing of food or beverages, and masks at all times."
Read the hospital's full statement below:
"The health and safety of our patients, employees, and physicians is our highest priority. 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. 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. Employees confirmed to have COVID-19 or suspected of having COVID-19 due to symptoms will not come to work, adhering to COVID-19 isolation protocols as per Kaiser Permanente and CDC guidance.
The Kaiser Permanente San Jose Medical Center is open and safe to receive care. All areas in the Emergency Department are undergoing deep cleaning, in addition to the already-rigorous cleaning protocols in effect. All our health care workers will be offered weekly testing for COVID-19 and expedited testing for anyone with symptoms or exposure to a person with COVID-19. Masks are required in all areas and we are further reconfiguring our processes and common spaces, such as staff break rooms, to limit any staff gatherings.
We are grateful to our employees, nurses, and physicians for their dedication to providing excellent and compassionate care every day. Nearly 40,000 Kaiser Permanente health care workers in Northern California have already received COVID-19 vaccinations, with more continuing each day, taking us a step closer to controlling the pandemic. Even as the vaccine is beginning to be provided in our communities, given the prevalence of COVID-19 in the community we are all still vulnerable and it remains critical for everyone to continue using the methods to help protect ourselves and others - especially masks, hand washing, avoiding gatherings, and social distancing."
Note: An earlier version of this story said Kaiser had 43 cases. Kaiser later updated the figure to 44.