Agency allows a stability budget of up to 2 weeks at -25°C
Tons of dry ice have been consumed, and hundreds of ultra low-temperature freezers sold to distributors and pharmacies in the Covid-19 vaccine supply chain, to meet Pfizer-BioNTech’s original requirement for shipping and storing the vaccine at -80°C to -60°C (-112°F to -76°F), prior to thawing and then administering to patients. Now, FDA, benefitting from new stability data provided by Pfizer, is allowing for looser temperature control: storage and shipping at -25°C to -15°C (-13°F to 5°F) for up to 2 weeks; the vaccine could be returned at least once to the ultra-cold storage; but overall, “total cumulative time the vials are stored at -25°C to -15°C (-13°F to 5°F) should be tracked and should not exceed 2 weeks.”
Was the initial restriction of ultra low-temperature storage and shipping a wasted effort? Hardly. Pfizer and FDA were following a well-thought-out process for allowing drug environmental conditions as per their clinical trial data, and then loosening the restrictions as real-world data came in. And this, in turn, reflects the extraordinary pace of going from a research idea to an approved treatment to meet the global pandemic.
“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,” said Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research. In practice, vaccination sites will be able to use the warmer freezers onsite as long as they track the duration of vaccine storage. After thawing (to 2-8°C), the vaccines can be held for up to 120 hours; and after warming to room temperature and dilution, administration needs to happen within 30 minutes.