The US Food and Drug Administration on Wednesday announced a big change in the way doses of Pfizer-BioNTech’s COVID-19 vaccine can be handled. From now on, undiluted vials of the mRNA vaccine can stay at normal refrigerator temperatures for up to a month rather than the previous limit of just five days.

The change has the potential to significantly ease storage issues and promote the use of the highly effective vaccine, which has been hindered in some settings by its ultra-cold storage requirements.

For long-term storage, the vaccine still requires ultra-cold freezer temperatures—between -80°C to -60°C (-112°F to -76°F). But the vials can be transported and temporarily stored at normal freezer temperatures—between -25°C to -15°C (-13°F to 5°F)—for up to two weeks. According to yesterday’s update, the undiluted vials can then be thawed and kept at normal refrigerator temperatures—between 2°C to 8°C (35°F to 46°F)—for up to a month. Once the vials are diluted and ready for use, they must be used within six hours, according to the FDA’s detailed handling guide.

The updated handling conditions are based on new vaccine stability data that Pfizer and BioNTech submitted to the FDA. The companies also submitted the data to the European Medicines Agency, which approved the change to required storage conditions on Monday.

In a statement, the FDA’s top vaccine regulator, Peter Marks, said:

Making COVID-19 vaccines widely available is key to getting people vaccinated and bringing the pandemic to an end. Pfizer Inc. submitted data to the FDA to support storage of undiluted, thawed vials of its COVID-19 vaccine for up to one month at refrigerator temperatures. This change should make this vaccine more widely available to the American public by facilitating the ability of vaccine providers, such as community doctors’ offices, to receive, store and administer the vaccine.

The change puts the Pfizer-BioNTech vaccine’s handling requirements more in line with Moderna’s COVID-19 vaccine, which is also an mRNA-based vaccine. Moderna’s vaccine requires long-term storage conditions of between -50°C to -15°C (-58°F to 5°F), but the vaccine can be kept at refrigerator temperatures for up to 30 days. Once the first dose is withdrawn from a vial, it must be used within 12 hours.