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Glad to hear it! One key advantage of the Moderna one versus the similar Pfizer/BioNTech vaccine is that it doesn't require deep freeze storage, only regular f

Glad to hear it! One key advantage of the Moderna one versus the similar Pfizer/BioNTech vaccine is that it doesn't require deep freeze storage, only regular freezing temperatures. (-90º C for Pfizer/BioNTech vs -20º C for Moderna)

lisper 6y ago
Does anyone here know the reason for the difference? They're both mRNA vaccines, right? So why does one need a deep freeze and the other one not?
- m-ee 6y ago
  Different lipid nano particles, or maybe just stability testing. The vaccines could be stable at lower temperatures but the companies haven’t had time to prove it by letting the vaccine sit in a fridge for months.
  - garmaine 6y ago
    At higher temperatures, you mean.
    - m-ee 6y ago
      Yes at higher temperatures
- bpodgursky 6y ago
  The answer is "there is probably no difference, but Moderna has more experience with mRNA vaccines and felt good about the -20 requirement, but Pfizer is new to mRNA, and didn't": https://www.npr.org/sections/health-shots/2020/11/17/935563377/why-does-pfizers-covid-19-vaccine-need-to-be-kept-colder-than-antarctica https://www.npr.org/sections/health-shots/2020/11/17/9355633...
  - refurb 6y ago
    As someone who has been involved in stability testing before, I doubt this is really the case. In order to justify your stability, you need data to submit to the FDA (they don't take your word for it). When doing your initial stability studies, you try and collect data for the most ideal conditions - no refrigeration needed, stable for X years from room temperature to 30C (to account for conditions during shipment). No doubt Pfizer lined up a number of early stability studies testing -80C, -50C, -20C, 0C, etc. They recognize that needing a -70C cold chain is a logistics hurdle. If they could avoid it at all, they would have pushed for it and had data to back it up.
    - seanwilson 6y ago
      > stable for X years from room temperature to 30C How do you get this data for a large value of X without having to wait X years?
      - Retric 6y ago
        The general rule is increasing temperature by 10C roughly doubles the rate of chemical reactions. https://www.ddltesting.com/package-testing/shelf-life-testing/ https://www.ddltesting.com/package-testing/shelf-life-testin... Though in practice it’s more complicated. Basically, make predictions based on accelerated testing and then validate them in real time tests. So, if things hold up at 3 and 6 months real time you can probably trust them over longer timeframes.
        maxerickson 6y ago
        In practice it seems the expiration dates on even boring drugs aren't real far into the future.
        Retric 6y ago
        Yea, prescription drug manufacturers have little incentives to seek multi year shelf lives. Combined with the slow approval process real time testing is likely considered sufficient. https://www.pharmacytimes.com/news/some-medications-last-long-past-expiration-date https://www.pharmacytimes.com/news/some-medications-last-lon...
- gnicholas 6y ago
  According to NPR [1] > Moderna spokesperson Colleen Hussey explained to NPR in an email that its vaccine doesn't need to be kept so cold because of its particular "lipid nanoparticle properties and structure," and because the company has learned from experience — it's developed ten mRNA vaccine candidates already. "Now we don't need [ultra-cold conditions] as the quality of product has improved and [it] doesn't need to be highly frozen to avoid mRNA degradation," Hussey explained. and > It's possible that Pfizer's vaccine could eventually be shown to be stable in somewhat warmer conditions — or for longer times out of the freezer. 1: https://www.npr.org/sections/health-shots/2020/11/17/935563377/why-does-pfizers-covid-19-vaccine-need-to-be-kept-colder-than-antarctica https://www.npr.org/sections/health-shots/2020/11/17/9355633...
  - ehsankia 6y ago
    Are they saying it's possible the existing BioNtech vaccine will be stable at lower temps or that they could make it with the alternative lipid? The latter would require another phase2/phase3 trial I assume, and you'd think they would've tested the former by now thoroughly.
    - gnicholas 6y ago
      My reading of the article is that they are testing to see whether the current formulation is not as temperature-sensitive as currently believed.
  - kart23 6y ago
    Read in between the lines for a moment. They're saying that the differences are secret, and they're not gonna release the specific structure of the LNPs and why the differences are there. The equivalent of having two proprietary binaries that both accomplish the same task, but have different code, and the reasons why are secret as well. And we're accepting this on the first mRNA vaccine ever to be used on a massive scale, all to protect their profits before the rest of the world can start producing vaccines. Yes they spent a lot of money and time creating the vaccine. Now open source it and let the rest of the world save their citizens.
- nerfhammer 6y ago
  Pfizer wanted to release as quickly as possible and didn't want to bother doing another study to tell
- hannob 6y ago
  I read that Pfizer/Biontech is currently testing whether they can go with higher temperatures, but those tests aren't finished yet, because the first priority was to get the patient data, and there they did what they expected will be safest and most likely to work. It may very well be that later on they'll change the freezing requirement later.
wycy 6y ago
Do both vaccines require 2 doses? Also, is the second dose different or just a duplicate of the first?
- throwaway201103 6y ago
  Both of the mRNA vaccines (Pfizer and Moderna) require two doses. Don't know if the 2nd dose is the same as the first.
  - Exmoor 6y ago
    Both the first and second doses of the mRNA vaccines are identical.
    - ehsankia 6y ago
      Yep, my understanding is that the mRNA eventually degrade and disappear from your system, but your system requires more time to build enough antibodies.
    - harimau777 6y ago
      Could the first dose be one the Pfizer one and the second be the Moderna one? That might make logistics somewhat easier.
      - IfOnlyYouKnew 6y ago
        no. Might work, isn't tested.
  - zaroth 6y ago
    The actual study results show the vaccine is highly effective within 10 days of the first dose. Honestly a bit shocked based on the results and the number of lives that could be saved by effectively doubling the number of available doses that they didn’t try to get it modified to a single dose regimen. Seems to me like just another way the FDA has screwed up this whole rollout.
neuronic 6y ago
Isn't the Pfizer/BioNTech one marked at this temp because they simply didn't have enough time to really figure out the safe temps? I recall reading an article that mentioned -90C as the "safe shot", meaning they can be 100% certain that the vaccine is stable at this temp but it might be stable at much lower temps. Also more BNT-XXX vaccines are in development.
- markus92 6y ago
  Pfizer is spending a considerable amount of money on their cold chain, for example buying up pretty much all ultra-low temperature freezers they can find. I personally doubt they'd still be spending that money if they needed it, there's been plenty of time for a stability analysis by now.
  - rualca 6y ago
    > I personally doubt they'd still be spending that money if they needed it, there's been plenty of time for a stability analysis by now. I don't believe your logic follows. There's a lot riding on this vaccine working as advertised, thus there is considerable pressure on Pfizer/BioNTech to deliver on that promise. If they know their vaccine is at peak effectiveness when transported at -90ºC and that the effectiveness drops if handled at lower temperatures, and if time is critical as it is, then they have all the reasons in the world to just play it safe by going with the costly but reliable option.
    - markus92 6y ago
      That's true, on the other hand, consider that Moderna has lowered storage requirements twice in the past four months. This gives us three options, Is it Moderna taking more risks, Pfizer being more risk-averse or is the Moderna one inherently more stable?
      - rualca 6y ago
        > That's true, on the other hand, consider that Moderna has lowered storage requirements twice in the past four months. Moderna's vaccine was the second to enter the US market. If Pfizer/BioNTech delayed their vaccine to work on lowering the temperature requirements, Moderna would eat their lunch, and Pfizer/BioNTech would be relegated to second place on the place it matters the most: the history books. As is, I'm sure that Pfizer/BioNTech are already working on improving temperature requirements, while leading the race. > This gives us three options, Is it Moderna taking more risks, Pfizer being more risk-averse or is the Moderna one inherently more stable? I have zero insight on the situation, thus I can't really tell. However, it's clear that each and every single actor in the story, from biotech companies to politicians and also regulatory bodies, is taking way more risks on this issue than what they would otherwise take.
loufe 6y ago
If anyone is curious how this difference will make an impact in the big picture, I cannot recommend highly enough the Youtube video on Covid vaccine logistics by Wendover Productions (I can't search youtube at work to provide a direct link but it should be easily searchable).

lisper 6y ago

Does anyone here know the reason for the difference? They're both mRNA vaccines, right? So why does one need a deep freeze and the other one not?

m-ee 6y ago
Different lipid nano particles, or maybe just stability testing. The vaccines could be stable at lower temperatures but the companies haven’t had time to prove it by letting the vaccine sit in a fridge for months.
- garmaine 6y ago
  At higher temperatures, you mean.
  - m-ee 6y ago
    Yes at higher temperatures
bpodgursky 6y ago
The answer is "there is probably no difference, but Moderna has more experience with mRNA vaccines and felt good about the -20 requirement, but Pfizer is new to mRNA, and didn't": https://www.npr.org/sections/health-shots/2020/11/17/935563377/why-does-pfizers-covid-19-vaccine-need-to-be-kept-colder-than-antarctica https://www.npr.org/sections/health-shots/2020/11/17/9355633...
- refurb 6y ago
  As someone who has been involved in stability testing before, I doubt this is really the case. In order to justify your stability, you need data to submit to the FDA (they don't take your word for it). When doing your initial stability studies, you try and collect data for the most ideal conditions - no refrigeration needed, stable for X years from room temperature to 30C (to account for conditions during shipment). No doubt Pfizer lined up a number of early stability studies testing -80C, -50C, -20C, 0C, etc. They recognize that needing a -70C cold chain is a logistics hurdle. If they could avoid it at all, they would have pushed for it and had data to back it up.
  - seanwilson 6y ago
    > stable for X years from room temperature to 30C How do you get this data for a large value of X without having to wait X years?
    - Retric 6y ago
      The general rule is increasing temperature by 10C roughly doubles the rate of chemical reactions. https://www.ddltesting.com/package-testing/shelf-life-testing/ https://www.ddltesting.com/package-testing/shelf-life-testin... Though in practice it’s more complicated. Basically, make predictions based on accelerated testing and then validate them in real time tests. So, if things hold up at 3 and 6 months real time you can probably trust them over longer timeframes.
      - maxerickson 6y ago
        In practice it seems the expiration dates on even boring drugs aren't real far into the future.
        Retric 6y ago
        Yea, prescription drug manufacturers have little incentives to seek multi year shelf lives. Combined with the slow approval process real time testing is likely considered sufficient. https://www.pharmacytimes.com/news/some-medications-last-long-past-expiration-date https://www.pharmacytimes.com/news/some-medications-last-lon...
gnicholas 6y ago
According to NPR [1] > Moderna spokesperson Colleen Hussey explained to NPR in an email that its vaccine doesn't need to be kept so cold because of its particular "lipid nanoparticle properties and structure," and because the company has learned from experience — it's developed ten mRNA vaccine candidates already. "Now we don't need [ultra-cold conditions] as the quality of product has improved and [it] doesn't need to be highly frozen to avoid mRNA degradation," Hussey explained. and > It's possible that Pfizer's vaccine could eventually be shown to be stable in somewhat warmer conditions — or for longer times out of the freezer. 1: https://www.npr.org/sections/health-shots/2020/11/17/935563377/why-does-pfizers-covid-19-vaccine-need-to-be-kept-colder-than-antarctica https://www.npr.org/sections/health-shots/2020/11/17/9355633...
- ehsankia 6y ago
  Are they saying it's possible the existing BioNtech vaccine will be stable at lower temps or that they could make it with the alternative lipid? The latter would require another phase2/phase3 trial I assume, and you'd think they would've tested the former by now thoroughly.
  - gnicholas 6y ago
    My reading of the article is that they are testing to see whether the current formulation is not as temperature-sensitive as currently believed.
- kart23 6y ago
  Read in between the lines for a moment. They're saying that the differences are secret, and they're not gonna release the specific structure of the LNPs and why the differences are there. The equivalent of having two proprietary binaries that both accomplish the same task, but have different code, and the reasons why are secret as well. And we're accepting this on the first mRNA vaccine ever to be used on a massive scale, all to protect their profits before the rest of the world can start producing vaccines. Yes they spent a lot of money and time creating the vaccine. Now open source it and let the rest of the world save their citizens.
nerfhammer 6y ago
Pfizer wanted to release as quickly as possible and didn't want to bother doing another study to tell
hannob 6y ago
I read that Pfizer/Biontech is currently testing whether they can go with higher temperatures, but those tests aren't finished yet, because the first priority was to get the patient data, and there they did what they expected will be safest and most likely to work. It may very well be that later on they'll change the freezing requirement later.

wycy 6y ago

Do both vaccines require 2 doses? Also, is the second dose different or just a duplicate of the first?

throwaway201103 6y ago
Both of the mRNA vaccines (Pfizer and Moderna) require two doses. Don't know if the 2nd dose is the same as the first.
- Exmoor 6y ago
  Both the first and second doses of the mRNA vaccines are identical.
  - ehsankia 6y ago
    Yep, my understanding is that the mRNA eventually degrade and disappear from your system, but your system requires more time to build enough antibodies.
  - harimau777 6y ago
    Could the first dose be one the Pfizer one and the second be the Moderna one? That might make logistics somewhat easier.
    - IfOnlyYouKnew 6y ago
      no. Might work, isn't tested.
- zaroth 6y ago
  The actual study results show the vaccine is highly effective within 10 days of the first dose. Honestly a bit shocked based on the results and the number of lives that could be saved by effectively doubling the number of available doses that they didn’t try to get it modified to a single dose regimen. Seems to me like just another way the FDA has screwed up this whole rollout.

neuronic 6y ago

Isn't the Pfizer/BioNTech one marked at this temp because they simply didn't have enough time to really figure out the safe temps? I recall reading an article that mentioned -90C as the "safe shot", meaning they can be 100% certain that the vaccine is stable at this temp but it might be stable at much lower temps. Also more BNT-XXX vaccines are in development.

markus92 6y ago
Pfizer is spending a considerable amount of money on their cold chain, for example buying up pretty much all ultra-low temperature freezers they can find. I personally doubt they'd still be spending that money if they needed it, there's been plenty of time for a stability analysis by now.
- rualca 6y ago
  > I personally doubt they'd still be spending that money if they needed it, there's been plenty of time for a stability analysis by now. I don't believe your logic follows. There's a lot riding on this vaccine working as advertised, thus there is considerable pressure on Pfizer/BioNTech to deliver on that promise. If they know their vaccine is at peak effectiveness when transported at -90ºC and that the effectiveness drops if handled at lower temperatures, and if time is critical as it is, then they have all the reasons in the world to just play it safe by going with the costly but reliable option.
  - markus92 6y ago
    That's true, on the other hand, consider that Moderna has lowered storage requirements twice in the past four months. This gives us three options, Is it Moderna taking more risks, Pfizer being more risk-averse or is the Moderna one inherently more stable?
    - rualca 6y ago
      > That's true, on the other hand, consider that Moderna has lowered storage requirements twice in the past four months. Moderna's vaccine was the second to enter the US market. If Pfizer/BioNTech delayed their vaccine to work on lowering the temperature requirements, Moderna would eat their lunch, and Pfizer/BioNTech would be relegated to second place on the place it matters the most: the history books. As is, I'm sure that Pfizer/BioNTech are already working on improving temperature requirements, while leading the race. > This gives us three options, Is it Moderna taking more risks, Pfizer being more risk-averse or is the Moderna one inherently more stable? I have zero insight on the situation, thus I can't really tell. However, it's clear that each and every single actor in the story, from biotech companies to politicians and also regulatory bodies, is taking way more risks on this issue than what they would otherwise take.

loufe 6y ago

If anyone is curious how this difference will make an impact in the big picture, I cannot recommend highly enough the Youtube video on Covid vaccine logistics by Wendover Productions (I can't search youtube at work to provide a direct link but it should be easily searchable).