Vials of Pfizer/BioNTech's coronavirus vaccine can be kept at normal freezer temperatures for short periods instead of in ultra-cold storage, the EU's drugs regulator said Friday.

The change would help the "rapid roll-out" of vaccines across Europe, where vaccination campaigns are stalling due to supply and logistical issues, the European Medicines Agency said in a statement.

The EU regulator had "given a positive opinion to allow transportation and storage of vials of this vaccine at temperatures between -25 to -15 degrees Celsius (-13 to 5 Fahrenheit)... for a one-off period of two weeks."

The EMA said this was the "temperature of standard pharmaceutical freezers"

"This is an alternative to the long-term storage of the vials at a temperature between -90 to -60 degrees Celsius in special freezers" the Amsterdam-based watchdog added in a statement.

"It is expected to facilitate the rapid roll-out and distribution of the vaccine in the EU by reducing the need for ultra-low temperature cold storage conditions throughout the supply chain."

The US made a similar decision about the Pfizer vaccine on February 25.

The Pfizer vaccine's high effectiveness against coronavirus has been tempered by the difficulty of storing and transporting the jab due to the need for super-cold conditions.