An employee at a Wisconsin medical center deliberately removed 57 vials of a COVID vaccine from refrigeration, prompting officials to dispose of nearly 500 doses.

Aurora Medical Center officials had initially suspected the Moderna coronavirus vaccines, which should be stored between 36°F and 46°F, had inadvertently been left out at the Grafton hospital on December 26.

On Wednesday, the officials investigated and found the employee “acknowledged that they intentionally removed the vaccine from refrigeration.”

The hospital, which is part of Advocate Aurora Health Care, has notified “appropriate authorities for further investigation,” adding that the employee is no longer working with Aurora.

“We continue to believe that vaccination is our way out of the pandemic,” the officials said. “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.”

Once removed from refrigerators, the vials can remain at room temperature for up to 12 hours, which allowed doctors to save some of the doses.

Aurora did not provide additional information. However, it said the officials would provide more details today.

As of Wednesday afternoon, Aurora Health Care said over 21,000 health workers had received the first dose of the vaccine at the company’s centers.

So far, Wisconsin has administered nearly 47,160 doses of the coronavirus vaccine. The Centers for Disease Control and Prevention (CDC) has recently said that the country has distributed more than 11 million doses of the Pfizer and Moderna COVID vaccine, with over 2 million of those doses were given to people as of Monday morning.