FDA gives Pfizer COVID-19 vaccine go-ahead for easier storage rules

The FDA has allowed more flexible Pfizer COVID-19 vaccine transportation and storage rules, after the pharmaceutical company released new evidence that the drug doesn't necessarily require the ultra-low temperatures first suggested. Pfizer announced the updated findings last week, having initially advised that the vaccine it developed with BioNTech needed to be kept at temperatures between -80ºC and -60ºC (-112ºF to ‑76ºF).

It was with that guidance that the US Food and Drug Administration (FDA) granted emergency use authorization for the vaccine, in late 2020. Still, it proved to be a headache for the supply chain, and for healthcare providers.

Pfizer developed a special, low-temperature delivery container for the vaccine candidate, which could be restocked with dry ice to maintain the safe temperature range. Still, it meant that the standard refrigeration in most locations couldn't get sufficiently cold. Today, though, the FDA allowed an update on the EUA based on the new evidence.

The preferred storage remains the ultra-low temperature freezers. However, the FDA will now permit the COVID-19 vaccine to be transported and stored at conventional temperatures, commonly supported by pharmaceutical freezers, for periods of up to two weeks. Even at that higher temperature, the vaccine should remain stable.

In fact, the updated guidance is even more flexible. Vaccine stored frozen at -25°C to -15°C (-13°F to 5°F) for less than two weeks can actually be returned to an ultra-low freezer if it can't be used in time, the FDA says. However, the total cumulative time vials are stored at the regular freezer temperatures must not exceed two weeks.

Unchanged are the rules for thawed vials, the process which takes place before the vaccine is to be used. Vials can be stored in a refrigerator for up to five days after being thawed, but before being diluted. Once diluted, they need to be used within 6 hours, but can be stored either at refrigerator temperature or room temperature. Doses administered are given at room temperature, and Pfizer still requires two doses – given roughly a month apart – for full efficacy of the drug.

Still, the changes are expected to make a sizable difference to how the immunization roll-out is managed in the coming months.

"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," Peter Marks, M.D., Ph.D., director of the FDA's Center for Biologics Evaluation and Research, said of the amendment to the EUA. "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."

Pfizer currently expects to supply the US government with 300 million doses of the Pfizer-BioNTech COVID-19 Vaccine, sufficient to vaccinate 150 million people.