1,900 doses of Moderna vaccine destroyed after cleaner accidentally unplugs freezer in Boston

Thousands of doses of Moderna's COVID-19 vaccine were destroyed after a cleaner in Boston accidentally unplugged the freezer in which they were being stored.

"On Tuesday, January 19, 2021, VA Boston Pharmacy staff discovered that a freezer at the Jamaica Plain campus failed. As a result, 1,900 doses of the Moderna Covid-19 Vaccine stored in the freezer were compromised," Kyle Toto, the public affairs specialist at VA Boston Healthcare System, said in a statement Thursday.

The Moderna vaccine doses arrive at their designated facilities frozen between -13 and 5 degrees Fahrenheit, according to the Centers for Disease Control and Prevention. They can then be kept frozen or stored in a refrigerator at between 36 and 46 degrees Fahrenheit, for up to 30 days before vials are punctured.

Toto said, the freezer at the Boston pharmacy "was in a secure location and had an alarm system installed. The plug was found loose after a contractor accidentally removed it while cleaning."

He said they are investigating why the incident occurred and why the alarm system did not work as it was supposed to.

"Replenishment doses are in process and we do not foresee disruption of our vaccination effort," Toto added.

ABC News' Kendall Coughlin contributed to this report.