A now former employee at a Wisconsin medical center "intentionally removed" 57 vials of a coronavirus vaccine from refrigeration, forcing officials to throw out nearly 500 doses, according to an internal investigation.

Aurora Medical Center officials had initially suspected the Moderna vaccines, which must be kept between 36° to 46°F, had inadvertently been left out at the Grafton hospital on Dec. 26. But an investigation found the individual "acknowledged that they intentionally removed the vaccine from refrigeration," officials said Wednesday.

The medical center, which is part of Advocate Aurora Health Care, has notified "appropriate authorities for further investigation" and added that the individual is no longer employed by Aurora.

"We continue to believe that vaccination is our way out of the pandemic. We are more than disappointed that this individual's actions will result in a delay of more than 500 people receiving their vaccine. This was a violation of our core values."

The vials can remain at room temperature for up to 12 hours. That allowed clinicians to salvage some of the doses.

As of Wednesday afternoon Aurora Health Care said more than21,000 health care workers had received the first of two injections at the company's centers.

A total of 47,157 of coronavirus vaccines have been administered in Wisconsin since vaccinations began over the last two weeks, according to state data.

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