Coronavirus | Pfizer vaccine can be stored at low temperatures for two weeks, company claims

‘As an alternative or complement to storage in an ultra-low temperature freezer’.

A helper prepares a vaccine from BioNTech/Pfizer. File

On Friday, the U.S.-based Pfizer claimed that its COVID-19 vaccine is stable when stored in low temperatures of minus 25°C to  minus 15°C, which are commonly found in pharmaceutical freezers and refrigerators. 

In a release, the company said data had been submitted to the FDA (Food and Drug Administration) to support a proposed update to the U.S. Emergency Use Authorization (EUA) Prescribing Information. It claimed that the vaccine could be stored at low temperatures for a “total of two weeks as an alternative or complement to storage in an ultra-low temperature freezer”.

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On December 11, 2020, when the FDA approved the vaccine for emergency use, the storage temperature stipulated was minus 60°C to minus 80°C. The

labels of the vaccine too state that the vaccine must be stored at temperatures between minus 80ºC and minus 60ºC (minus 112ºF to minus 76ºF). The vaccine remains stable at ultra-low temperature for up to six months.

The data submitted to the FDA included low temperature (minus 25ºC  to minus 15ºC) stability data generated on batches manufactured over the past nine months of COVID-19 vaccine development. It includes “batches that supplied the earliest clinical trials through the commercial scale batches currently in production. These data also will be submitted to global regulatory agencies within the next few weeks”.

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Stability studies 

Albert Bourla, Chairman and Chief Executive Officer, Pfizer, said in the release: “We have been continuously performing stability studies to support the production of the vaccine at commercial scale, with the goal of making the vaccine as accessible as possible for healthcare providers and people across the U.S. and around the world.”

Ugur Sahin, CEO and Co-founder of BioNTech said in the release, “The data submitted may facilitate the handling of our vaccine in pharmacies and provide vaccination centers an even greater flexibility.”

He stated, “We will continue to leverage our expertise to develop potential new formulations that could make our vaccine even easier to transport and use.”

Before mixing with a saline diluent prior to administering the vaccine, the dose may also be refrigerated for up to five days at standard refrigerator temperature, between 2ºC and 8ºC. “If approved, the option to store at minus 25°C to minus 15°C for two weeks would be in addition to this five-day option to store at standard refrigerator temperature,” the release said.

Even the developed countries did not have large numbers of ultra-low storage facilities at the time of approval. The ultra-low temperature required to store and transport the vaccine meant that most developing countries, which do not have the deep-freezer infrastructure, may not be able to handle the vaccine for large-scale immunisation.