A hospital worker in Wisconsin said they removed COVID-19 vaccine vials from refrigeration on purpose, causing spoilage of more than 500 doses.
Advocate Aurora Health, which runs hospitals in Wisconsin and Illinois, learned earlier this week that 57 vials of Moderna's COVID-19 vaccine were removed from a pharmacy refrigerator at Aurora Medical Center in Grafton.
An internal review was launched to probe what happened, and officials initially thought the action was caused by "inadvertent human error," Advocate said in a statement to news outlets.
"The individual in question today acknowledged that they intentionally removed the vaccine from refrigeration," it added.
The person was fired and Advocate notified the authorities.
"We continue to believe that vaccination is our way out of the pandemic. We are disappointed that this individual's actions will result in a delay of more than 500 people receiving their vaccine," Advocate said.
The Grafton Police Department confirmed in a statement that officers were informed about a hospital employee allegedly tampering with vials of the vaccine.
The department said it is investigating, along with the FBI and the Food and Drug Administration (FDA).
The first two COVID-19 vaccines approved for emergency use by the administration, including Moderna's, require refrigeration. The hospital said most of the vials that were removed went bad and had to be thrown out, though some of the doses were administered within the approved 12-hour window for injections post-refrigeration.
According to the FDA's authorization, Moderna vials are stored frozen between -13 degrees Fahrenheit and 5 degrees Fahrenheit. The vials can be stored between 36 degrees and 46 degrees for up to 30 days before first use. Unpunctured vials may be stored between 46 degrees and 77 degrees for up to 12 hours.
According to Wisconsin health authorities, over 47,000 COVID-19 vaccine doses have been administered in the state as of Dec. 29, including 6,306 doses of Moderna's vaccine.
Nationwide, 2.79 million people have been vaccinated as of 9 a.m. on Dec. 30, according to a tracker from the Centers for Disease Control and Prevention.