"Keeping Coronavirus Vaccines at Subzero Temperatures During Distribution Will Be Hard, But Likely Key to Ending Pandemic"

quote Trucks, planes and storage facilities all need to be able to keep a vaccine cold.

quote Most vaccines need to be stored within 1 degree Fahrenheit of their ideal temperature. Traditional vaccines are usually stored between 35 degrees Fahrenheit and 46 degrees Fahrenheit, but some of the leading COVID-19 vaccines need to be stored at much colder temperatures. Moderna’s vaccine requires a storage temperature of minus 4 degrees Fahrenheit, whereas Pfizer’s vaccine candidate requires a storage temperature of minus 94 degrees Fahrenheit. These are not easy temperatures to maintain accurately. A study from 2019 estimated that 25% of vaccines are degraded by the time they arrive at their destination. If a vaccine is exposed to temperatures outside its range, and this gets noticed, then the vaccines are always thrown away. Rarely, a temperature mistake is missed and one of these vaccines is administered. Research shows that these vaccines won’t cause any adverse effects, but could offer decreased protection and might require a patient to be revaccinated. Temperature mistakes are mostly due to inappropriate shipping procedures in the cold chain, and these losses are estimated at US$34.1 billion annually. But that number does not even take into account the cost – physically as well as financially – of any illnesses that could have been prevented by timely deliveries of high-quality vaccines.

I am gobsmacked at the large difference between the temperature requirements for the Moderna vaccine candidate (-4 F) and Pfizer's candidate (-94 F.)

These are both mRNA (messenger RNA) vaccines, which is a kind of vaccine that has not ever been used before in a full scale human vaccination program. There is a track record for mRNA vaccines in the veterinary field and for vaccinating livestock.

If you feel like reading more about this, you can hook up with Anna Nagurney's very excellent report in Discover magazine; September 24, 2020.
https://www.discovermagazin...-during-distribution


If you're into more "looming questions", STAT's Helen Branswell and Ed Silverman have you (well) covered.

"7 looming questions about the rollout of a Covid-19 vaccine"
Helen Branswell and Ed Silverman for STAT; October 9, 2020.
https://www.statnews.com/20...-a-covid-19-vaccine/

[This message has been edited by rinselberg (edited 10-12-2020).]

I know a little about cold chain and refrigerated transport and distribution. I will say that the Pfizer vaccine requiring -70C is a difficult to manage for several reasons. 1) I am not aware of any commercial distribution locations that can maintain -70C. Typically -70C is more the range for smaller laboratory freezers, going much colder is the limits of mechanical refrigeration. -70C is also too warm for "common" chemical refrigeration...aka nitrogen vapor, which in the right conditional is also used for cryogenic storage. Then there is another danger below -70 C, ( approx -75 C if i recall correctly) which is the "glass inflection point" for biologics where if an item is frozen below and then warms up it will cause crytals insid eof the cells which "explode" the biologic from the inside out much like popcorn.

The normal ranges of -20 C is not easy to keep it is also a lot more realistic. Mechanical refrigeration at these temperautres is easy and common. -20C is a common temperature used for flash freezing such as ice cream, or frozen vegetables; so storage facilties and even refrigerated trialers can reach these temperatures. While the range is more common for food, the qualification of facilities and trucks is very different when used for vaccines. Think of it this way we make ice cream everyday and deliver it to your local grocery store while -20C is cold, it is a realively an easy nut to crack.

Just be glad that ranges of these vaccines are not truly cryogenic ranges where threre is truly no distribution capacity in terms of storage and distribution. I will admit there is infrastructure for cryogenic storage and distribution mainly for R&D but nothing at commercial scale.


When vaccaiens are made there will be ~20,000 to 30,000 doses per pallet so anywhere between 33 to 50 pallet spaces wil be needed to store ( and transport) ~1 million doses. just adding this to give some scale of the problem that needs to be solved.