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expert reaction to Pfizer press release saying Pfizer and BioNTech have submitted to the US FDA data on stability of their vaccine at standard freeze temperatures

It has been announced that Pfizer and BioNTech have submitted their COVID-19 vaccine stability data at standard freeze temperature to the U.S. FDA.


Dr Peter English, Consultant in Communicable Disease Control, Former Editor of Vaccines in Practice Magazine, Immediate past Chair of the BMA Public Health Medicine Committee, said:

“The requirement to store the Pfizer-BioNtech vaccine at dry-ice ‘ultra-cold’ temperatures until shortly before the vaccine is used has caused some problems, as there is not an existing and widespread infrastructure for storing pharmaceuticals that way.  My guess would be that they store the product that way in their research facilities, and had not been able to do the necessary testing in time, prior to release as soon as possible so the product could be used, to ensure that lower temperature storage would suffice.

“It would appear that they have now been able to do enough testing to be confident that the vaccine remains stable if stored at ordinary freezer temperatures, rather than ‘ultra-cold’ temperatures, for up to 2 weeks before use, and have submitted new data to the U.S. Food and Drug Administration (FDA) to this effect.

“I would not be surprised if, as time goes by and the period of storage prior to testing increases, they will be able to increase this period.

“This is likely to make the infrastructure requirements considerably easier.

“I think that in USA it is not uncommon for vaccines to be shipped and stored frozen, being thawed shortly before use; but that in the UK this is unusual.  Indeed, many (non-Covid) vaccines are more vulnerable to damage through freezing than they are to damage from warming up above the stated temperature range.  So this might be less of an advantage in the UK than it is in the United States.  Nevertheless, it seems likely that it will facilitate transport and storage of the vaccine.

“This change will not alter the requirement to thaw the vaccine – without it getting above vaccine fridge temperatures – and to extract it from multi-use vials.  Ideally, vaccines are packaged and shipped in pre-filled syringes.”



All our previous output on this subject can be seen at this weblink:



Declared interests

Dr Peter English: “No interests to declare.”

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