On Feb. 25, 2021, the U.S. Food and Drug Administration announced that it was allowing undiluted frozen vials of the Pfizer-BioNTech COVID-19 Vaccine to be transported and stored at conventional temperatures commonly found in pharmaceutical freezers for a period of up to two weeks.

This reflected an alternative to the preferred storage of the undiluted vials in an ultra-low temperature freezer between -80ﾺC to -60ﾺC (-112ﾺF to -76ﾺF).