OT: Pfizer vaccine and cold storage

Ice cream was never served at -80C. It would have 'burned' you. Torn the skin off your lips.

There are rules concerning the carriage of dry-ice by air though.

It's coming through the chunnel.

assuming you could actually get your spoon into it.

The terms of the vaccine license seem to be very prescriptive with a limited number (4) of temperature controlled movements and block of thawed vaccine having to be used ASAP after thawing.

mRNA is intrinsically unstable and will begin to deteriorate from the moment that it is thawed. That in part is why they need the supercold freezer ice isn't quite icy enough at -20C. Chemical reactions slow down exponentially with decreasing temperature.

mRNA molecules are not very stable. Their lifetime is quite limited at ambient temperatures and not all that good as -20C either. Chemical reactions slow down exponentially with lowered temperature.

It might not strictly *need* -80C but that is the next lowest convenient passive freezing technology of dry ice. After that it is LN2.

I am a bit surprised it survives long enough in a human body at 37C when injected to actually work but evidently it does!

They know the molecules being used for this are very fragile. TBH I'm surprised that it is good for as long as a week in a fridge.

They can use the freezer part of my fridge freezer if they like. Even "soft scoop" ice cream is hard as iron.

But the Frenchies will intercept it. "Die, you rosbif scum ... you leave ze EU, you veel not live to tell ze tale!"

Well...yes, of course. But all it would need would be better insulation - not hard to come by these days.

Ah, I see. Thanks for that.

Perhaps take up is fairly rapid. Is the mRNA fragment more stable inside a cell? Or are the cell processes very rapid?

As I understand, even in hospitals -70 C is not regularly required for storage of this type.

The Astra-Zenica vaccine is much more tolerant and can be stored in existing freezers.

The USA has already arranged special rules to permit larger than usual quantities of dry ice to be carried by air. Though I think they have to take some additional precautions. Five time usual quantity if I remember correctly. No idea if anyone else has done similarly.

The Scottish government has bought 23 ultra-low temperature freezers to store the vaccine:

I thought Oxford / AstraZenica could be stored in a fridge?

I think you are right. I relied on memory which was that it could be distributed at cold chain temperatures but needed freezing for storage. I see there are claims it can be stored for six months in refrigerator temperatures.

Probably. All they've got to do is nip across from the nucleus to a nearby ribosome.

Strict control of distribution seems to be the key issue. Some similarity with distributing frozen food with a "do not refreeze" label. How can you be sure that it hasn't been thawed and refrozen one or more times in transit?

So make sure that initial distribution is to centres with proper freezing capability and that it transits and arrives still frozen in the original packaging.

Then distribute directly to a location which can use all of the doses in a short time; that is a mass vaccination centre.

Otherwise you could get little packages of thawed vaccine all over the place (including fakes) whith no guarantee that they are still viable.

Very strict control of a very short supply chain makes a lot of sense for this particular vaccine.

Vaccinating people with denatured vaccine leads to a whole world of hurt.

Cheers

Dave R

Moderna has also used the RNA approach and have produced a vaccine that can be stored at -20C.

Either electronic data loggers, or various "cards" can be stuck to products to indicate it has breached temperature, shock, humidity limits etc in transport.

I notice that company does mention covid vaccines, but doesn't seem to have a product for the -80 degree, just for -18 degree

Hmm, one issue I have not seen mentioned is, if it has to be that cold, if somebody injected that temperature stuff into me, I'd get frostbite at the injection site, also of course as the body is warm, how does the vaccine still survive long enough to latch onto cells to make the protein needed to start the immunity process off with this safe fragment made in our own bodies. Brian