How Did They Dicover That The New Vaccine Has To Be Kept At -70 (Or -80)?

[Bert45]

I have heard -70 and -80 mentioned on TV reports. Which is it? This is much colder than any freezer is capable of. How are they going to store this vaccine at such low temperatures? And how did they discover this? I imagine a scenario: they have a vaccine and it works for a day or two, but after three days in the fridge it stops working. (They store things in the fridge, because that's what you do. I've heard of problems with medicines that have to be kept 'cool' when they are used in hot climates.) It takes two weeks, at least, to find that the vaccine has stopped working. So they try keeping it in a freezer (-18). That doesn't work. Why try keeping it any colder? Why not? So where do you find a storage system at -70 or -80? There are university Low Temperature Physics Departments that use -272, but I don't suppose many are working at -70 or -80. If there is a medical section, I'd put my question there.

[woofgang]

he does.....needs keeping super cold for long term storage and transport, has limited but acceptable storage time in a normal fridge for administering it. I suspect that the 48 hour figure could be the minimum time that is logistically acceptable to ensure minimum waste.

[theprof]

THECORBYLOON, I think you'll find that the S of S was referring to fluctuation of temperature rather than a higher temperature.

Common sense would indeed seem to point to a reduction of efficacy of the vaccine if the storage temperature was reduced by -10 degrees C from that intended. However, this is not the case here. The efficacy is indeed reduced but by a very negligible amount that for all practical purposes can be ignored.

I chose not to discuss some issues over the containers provided by Pfizer but now it's become necessary. The long and short of it is that no portable container can maintain the same temperature as the ULT for hours/days on end. If they could, we wouldn't need the freezers as I can knock up in a lab a suitably enclosed freezing mix (see my answer above). In a nutshell, the container contents are regarded as viable and fine if upon unsealing, the vials are at -70 degrees C or colder.

I'm puzzled about your second paragraph. The vaccine returns to ULT storage when it enters the country of destination. The vaccine temperature can be raised at the immunisation centre by allowing the temperature to rise in a medical fridge or by other means. If long journeys are necessary within that host country then the Pfizer transportation container is redeployed but other equipment is available.

[theprof]

THECORBYLOON, just to clarify, the five day period refers to the length of time the vials can be stored in a medical fridge at an immunisation centre before being discarded.

It's important to understand that the vaccine cannot be transported from the manufacturing plant to the immunisation centre at precisely the same temperature. I've just realised I've not even discussed how they got the vials over the Atlantic Ocean into my research facilities!

If there are any further questions, I'll do my best to answer them.

[woofgang]

theprof...I think it might be just an opportunity to have a pop at Matt Hancock

[theprof]

THECORBYLOON, I think it's best if we don't begin to speculate on precisely who should have what knowledge about this vaccine and its use. No one has complete knowledge of covid-19 and the situation changes daily.

[theprof]

It had occurred to me woofgang!

[woofgang]

see theprof I knew you were bright :)

[Bert45]

Thanks to all respondents. It's hard to pick a best answer. I've certainly learned a lot. In fact, on the TV news they had a reporter standing next to a freezer that could store the vaccine at -70 (or-80). I never knew they were so available. I have a new question, I'll start a new thread.