The US Food and Drug Administration (FDA) has approved more flexible storage and transportation conditions for Pfizer-BioNTech’s Covid-19 vaccine.

The new ruling allows Pfizer-BioNTech’s vaccines to be stored at standard freezer temperatures for up to two weeks and potentially impacts the demand for dry ice, which has been high since the development of the vaccine from last summer.

“Pfizer submitted data to the FDA to support this alternative temperature for transportation and storage,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.

“This alternative temperature for transportation and storage of the undiluted vials is significant and allows the vials to be transported and stored under more flexible conditions. The alternative temperature for transportation and storage will help ease the burden of procuring ultra-low cold storage equipment for vaccination sites and should help to get vaccine to more sites.”

This is a change from the previously preferred storage of the undiluted vials in an ultracold temperature freezer between -80ºC to -60ºC (-112ºF to -76ºF), which pharmaceutical and distribution companies have achieved through shipping the vials in a special thermal container packed with dry ice to maintain that temperature range, or by using freezers that utilise liquid nitrogen.

Earlier this month, Pfizer-BioNTech submitted new temperature data to the FDA to support an update to the current label that would allow vials to be stored at -25 to -15 degrees Celsius (-13°F to 5°F) for a total of two weeks. 

The alternative temperature for storage of frozen vials is not applicable to the storage of thawed vials before dilution (which can be held in the refrigerator for up to five days), or on the storage of thawed vials after dilution (which can be held at refrigerator temperature or room temperature for use within six hours).