Grafton, Wis.-based Aurora Medical Center discarded 50 vials containing 500 doses of Moderna's vaccine after they were accidentally left out overnight Dec. 26, according to local CBS affiliate WDJT.
"Our internal review determined that as a result of unintended human error, the vials were not replaced in the refrigerator after being temporarily removed to access other items," Milwaukee-based Advocate Aurora Health said in a statement sent to local news outlets.
Some of the vaccine was administered to team members "within the approved 12-hour post-refrigeration window," though most had to be discarded, officials said. So far, 17,000 team members across the health system have been vaccinated.
A spokesperson from the state's health department said they're unaware of this happening anywhere else in Wisconsin, according to local ABC affiliate WISN.