Scrutable

headshot wrote: ↑

Thu Nov 12, 2020 5:00 pm

Two doses needed though...

What that means is that if you deliver, say, 4 million shots in the first month, then after two months you've done 4 million people. Which sounds obvious when you spell it out, but that's the way you need to think about it when calculating how soon you will get a certain amount of coverage.

AMS wrote: ↑

Thu Nov 12, 2020 6:20 pm

Dry ice is a solid.

There's a clue in the name...

The clue is also in the name of "liquid CO2", which exists at room temperature above about 5 atm, so you can keep it in a tank without special cooling and make dry ice from it when the dry ice which is cooling your vaccines has sublimated away.

AMS wrote: ↑

Thu Nov 12, 2020 6:23 pm

AMS wrote: ↑

Thu Nov 12, 2020 6:20 pm

shpalman wrote: ↑

Thu Nov 12, 2020 5:13 pm

"At any point, the boxes can be recharged with dry ice"

Assuming you have some tanks/cylinders of liquid CO2 to hand.

Dry ice is a solid.

Also, it's easy to handle. We routinely use it at work as the packing agent for frozen shipments, including international stuff. I bet there are some on nearly all Fedex transatlantic flights.

Here's how to not handle it: https://www.salon.com/2002/10/03/askthepilot13/

lpm wrote: ↑

Thu Nov 12, 2020 4:33 pm

If we can do 300,000 Covid tests per day, why can't we do 300,000 vaccinations per day? It's easier. No need for lab resources. Just a queue, a gazebo with people stabbing arms, a post-jab resting place to check for allergic reactions.

As I said on another thread, it's hard thinking about these stupidly big numbers. 300,000 vaccinations per day is 0.05% of the population. Assume an average GP list of 10,000 (a bit high), that's 50 patients per day per GP. Say an hour per day per GP - doable but something else would have to give.

Alternatively, consider a centralised provision. For a moderate sized town of 200,000, that's 1000 per day or a couple per minute. Possible if you've got a full-time team of say a dozen staff on a site with good road access.

That sort of high-level view suggests to me that it would be challenging but possible to deliver that level of throughput with sufficient organisation.

AMS wrote: ↑

Thu Nov 12, 2020 6:20 pm

shpalman wrote: ↑

Thu Nov 12, 2020 5:13 pm

"At any point, the boxes can be recharged with dry ice"

Assuming you have some tanks/cylinders of liquid CO2 to hand.

Dry ice is a solid.

Dry ice manufacturing starts with liquid carbon dioxide held under pressure (300 psi) in bulk storage vessels. To begin making dry ice, the liquid C02, is sent through an expansion valve into an empty chamber where under normal atmospheric pressure it flashes into C02 gas. This change from liquid to gas causes the temperature to drop quickly. About 46% of the gas will freeze into dry ice snow.

link

shpalman wrote: ↑

Thu Nov 12, 2020 7:22 pm

The clue is also in the name of "liquid CO2", which exists at room temperature above about 5 atm, so you can keep it in a tank without special cooling and make dry ice from it when the dry ice which is cooling your vaccines has sublimated away.

Fair point about how it's made, but that's not needed to top up the cryoprotection in a vaccine distribution network, which was the point. (In much the same way as they won't have to think about how to refine the oil into diesel for all the lorries they'll need.) The distributors will buy in tne pellets in bulk, which is already a factor in the supply chain for temperature sensitive reagents.

Sciolus wrote: ↑

Thu Nov 12, 2020 7:26 pm

300,000 vaccinations per day is 0.05% of the population.

0.44% of the UK population of 68 million.

shpalman wrote: ↑

Thu Nov 12, 2020 5:13 pm

Assuming you have some tanks/cylinders of liquid CO2 to hand.

Let's hope that no part of this process involves anything that might get stuck in a queue of lorries at Calais.

They will probably air freight this in, to be honest.

AMS wrote: ↑

Thu Nov 12, 2020 8:14 pm

shpalman wrote: ↑

Thu Nov 12, 2020 7:22 pm

The clue is also in the name of "liquid CO2", which exists at room temperature above about 5 atm, so you can keep it in a tank without special cooling and make dry ice from it when the dry ice which is cooling your vaccines has sublimated away.

Fair point about how it's made, but that's not needed to top up the cryoprotection in a vaccine distribution network, which was the point. (In much the same way as they won't have to think about how to refine the oil into diesel for all the lorries they'll need.) The distributors will buy in tne pellets in bulk, which is already a factor in the supply chain for temperature sensitive reagents.

So the pellets will arrive on other trucks, in thermal vessels similar to the ones with the vaccine in, but without any vaccines in?

We get dry ice deliveries to the lab. It comes in big plastic bags, probably 10 kg a bag at a guess. These have sufficient thermal mass that you can leave them lying around at room temperature long enough to cart them round the building. They get emptied into a big thermally insulated box, a bit like a big cool box. I really don't see this as the hard bit of the logistics!

AMS wrote: ↑

Thu Nov 12, 2020 8:46 pm

We get dry ice deliveries to the lab. It comes in big plastic bags, probably 10 kg a bag at a guess. These have sufficient thermal mass that you can leave them lying around at room temperature long enough to cart them round the building. They get emptied into a big thermally insulated box, a bit like a big cool box. I really don't see this as the hard bit of the logistics!

You can buy it at the supermarket round my way.

It seems there may be a shortage coming up which will cause problems, but moving CO2 around doesn't seem to be the limiting factor here.

So, a thermal sensor on a lorry somewhere on a motorway indicates that it needs more dry ice, and thanks to the GPS you know where it is. What, the driver stops off at a supermarket to buy a bag and tops up the relevant cool box?

sTeamTraen wrote: ↑

Thu Nov 12, 2020 8:17 pm

Sciolus wrote: ↑

Thu Nov 12, 2020 7:26 pm

300,000 vaccinations per day is 0.05% of the population.

0.44% of the UK population of 68 million.

Sorry, yeah, dunno where that stray zero came from. The rest of my numbers should be correct, in a spherical-cow way.

Lots of comments about cold chain. Google reefer container, refrigerated shipping containers that are suitable to -65 C and used for shipping e.g. organic peroxides.

Dry ice is convenient in a lab, but Arrhenius rules and -65 C will be a pretty good alternative to -78 C for shipping.

shpalman wrote: ↑

Thu Nov 12, 2020 9:40 pm

So, a thermal sensor on a lorry somewhere on a motorway indicates that it needs more dry ice, and thanks to the GPS you know where it is. What, the driver stops off at a supermarket to buy a bag and tops up the relevant cool box?

I was thinking about how available it would be, not how easy it is to "recharge". I'm not sure what that means. That could mean an automatic process, or the driver getting out and refilling from a bucket, or anything in between.

But it seems (in the US at least) that chains are already set up to get dry ice wherever it needs to go.

shpalman wrote: ↑

Thu Nov 12, 2020 9:40 pm

So, a thermal sensor on a lorry somewhere on a motorway indicates that it needs more dry ice, and thanks to the GPS you know where it is. What, the driver stops off at a supermarket to buy a bag and tops up the relevant cool box?

Temperature sensitive stuff can be shipped with temperature monitors inside the packaging. You worry less about how much dry ice is left and more about the sample temp.

Also, a sealed box with dry ice will make it from Belgium to the UK without needing a top up. I've regularly had to send or receive frozen samples to / from the US, and there is always plenty of dry ice left in the box.

Surely not an airtight seal or it would go bang?

bolo wrote: ↑

Fri Nov 13, 2020 12:59 am

Surely not an airtight seal or it would go bang?

Sorry - couldn't resist...

AMS wrote: ↑

Thu Nov 12, 2020 11:38 pm

shpalman wrote: ↑

Thu Nov 12, 2020 9:40 pm

So, a thermal sensor on a lorry somewhere on a motorway indicates that it needs more dry ice, and thanks to the GPS you know where it is. What, the driver stops off at a supermarket to buy a bag and tops up the relevant cool box?

Temperature sensitive stuff can be shipped with temperature monitors inside the packaging. You worry less about how much dry ice is left and more about the sample temp.

Also, a sealed box with dry ice will make it from Belgium to the UK without needing a top up. I've regularly had to send or receive frozen samples to / from the US, and there is always plenty of dry ice left in the box.

I'm specifically referring to this bit of the graphic (which reads right to left). Pfizer have means to check that the cold chain is intact, which is good, but recharging a box with dry ice means having immediate access to more dry ice while out on a road somewhere. (Or it means carrying fewer boxes of vaccines in order to cart spare dry ice around.)

I doubt it's even an issue since nowhere in the UK is really that far from an airport but then why put it in the graphic?

shpalman wrote: ↑

Fri Nov 13, 2020 1:44 pm

AMS wrote: ↑

Thu Nov 12, 2020 11:38 pm

shpalman wrote: ↑

Thu Nov 12, 2020 9:40 pm

So, a thermal sensor on a lorry somewhere on a motorway indicates that it needs more dry ice, and thanks to the GPS you know where it is. What, the driver stops off at a supermarket to buy a bag and tops up the relevant cool box?

Temperature sensitive stuff can be shipped with temperature monitors inside the packaging. You worry less about how much dry ice is left and more about the sample temp.

Also, a sealed box with dry ice will make it from Belgium to the UK without needing a top up. I've regularly had to send or receive frozen samples to / from the US, and there is always plenty of dry ice left in the box.

I'm specifically referring to this bit of the graphic (which reads right to left).
rps20201113_143905.jpg
Pfizer have means to check that the cold chain is intact, which is good, but recharging a box with dry ice means having immediate access to more dry ice while out on a road somewhere. (Or it means carrying fewer boxes of vaccines in order to cart spare dry ice around.)

I doubt it's even an issue since nowhere in the UK is really that far from an airport but then why put it in the graphic?

Was it here that someone was saying the letting compressed CO2 expand into a fabric bag can convert up to 43% by weight into dry ice?
Also, I was reading earlier about Dry Ice in Dewar jars being able to keep items below -70C for a week.

I don't think it's a particular technological stretch to maintain the cold chain, but putting it in the graphic is for people who say "Ah, but what about...."

Gfamily wrote: ↑

Fri Nov 13, 2020 2:20 pm

shpalman wrote: ↑

Fri Nov 13, 2020 1:44 pm

AMS wrote: ↑

Thu Nov 12, 2020 11:38 pm

Temperature sensitive stuff can be shipped with temperature monitors inside the packaging. You worry less about how much dry ice is left and more about the sample temp.

Also, a sealed box with dry ice will make it from Belgium to the UK without needing a top up. I've regularly had to send or receive frozen samples to / from the US, and there is always plenty of dry ice left in the box.

I'm specifically referring to this bit of the graphic (which reads right to left).
rps20201113_143905.jpg
Pfizer have means to check that the cold chain is intact, which is good, but recharging a box with dry ice means having immediate access to more dry ice while out on a road somewhere. (Or it means carrying fewer boxes of vaccines in order to cart spare dry ice around.)

I doubt it's even an issue since nowhere in the UK is really that far from an airport but then why put it in the graphic?

Was it here that someone was saying the letting compressed CO2 expand into a fabric bag can convert up to 43% by weight into dry ice?

Yes, you could do that, assuming you have some tanks/cylinders of liquid CO2 to hand.

I mean, it is possible they aren't total morons.

For example, if a substance needs to be kept at below 2°C, you could wait til it gets to 1.9°C and then hope that somebody nearby has immediate access to dry ice.

Or, you could watch it rise from -80°C to, say, -10°C, perhaps even keeping track of the rate of change, and send a notification saying "this needs to go back into deep freeze within 24/48 hours" or whatever.

And even then, given that it can apparently last quite a while between recharges, the tracking tech is probably more of a failsafe in case of equipment failure than a critical part of the distribution system.

The vaccine is going to be used in rich countries, which have loads of fridges and electricity and fast roads and reliable trucks. Distributing the vaccine is going to be easy.

In poor countries they might have to get people to distribute themselves closer to suitable vaccine storage areas, if they get a vaccine at all, but then again it's probably mostly people who live in places that have solar panels and generators that are more at risk of catching the virus anyway.

Dr ZDogg did a live stream a couple days ago on the Pfizer vaccine that's very much worth a watch (assuming you're on FB) https://www.facebook.com/watch/live/?v=1781394635348330

Russian Phase 3 trial results announced as 92% effective, amid some skepticism.
https://www.nature.com/articles/d41586-020-03209-0

Putin has asked Macron for French help in producing the Russian vaccine.
https://www.challenges.fr/entreprise/sa ... ron_736652

Meanwhile, the Russian healthcare system is under severe strain: https://thebarentsobserver.com/en/covid ... -hospitals

As Russia reports record cases: https://www.themoscowtimes.com/2020/11/ ... ons-a72046