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DiceMaster t1_j9u7jlq wrote

Reply to comment by sciolycaptain in Does the common flu vaccine offer any buffer against H5N1 (Bird Flu)? by Esc_ape_artist

How long can flu vaccines last in cryo storage? Could it make sense to have tons of h5n1 vaccine stockpiled just in case?

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sciolycaptain t1_j9u8fp0 wrote

Influenza vaccines can't be frozen without having decreased efficacy. They have a narrow window of temps they can be stored in a refrigerator, and once room temperature, must be used within 72 hours.

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DiceMaster t1_j9uahwa wrote

"Cryo" may not have been the exact word I was looking for. How long do they last, sealed and in a fridge?

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boooooooooo_cowboys t1_j9uqop3 wrote

I don’t know that there is much solid data to address that question. Typically flu vaccines are tailored to whatever strains are circulating in a given season, so they’re just thrown away at the before the next flu season.

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aphilsphan t1_j9urj8k wrote

There will be solid data somewhere, and generally an expiry date on the label. The manufacturer would have done or sponsored shelf life stability tests.

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xanthraxoid t1_j9uyoii wrote

It's worth noting that these tests aren't completely comprehensive. Recall that the nominal shelf life of various Covid vaccines was extended a couple of times - the initial results were interpreted conservatively, but over time more evidence allowed a more confident prediction of a longer shelf life.

When it comes to a vaccine that's not expected to be useful more than ~6 months into the future (nobody's taking the flu jab in the spring, and next year they'll want the new one) there's not really much point in measuring how it lasts beyond that with any degree of rigour.

Providing the shelf life is expected to be good enough for "this year's flu season" (3 months?) they'll most likely just use that figure and move on to more valuable work.

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NotAnotherEmpire t1_j9u8ok4 wrote

Tons, no. We don't know what the antigens of a future pandemic strain would be.

The USA does try to keep an updated stockpile of H5N1 vaccine, at least enough for doctors, first responders and the armed forces.

https://pubmed.ncbi.nlm.nih.gov/28554058/

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DiceMaster t1_j9uazju wrote

> The USA does try to keep an updated stockpile of H5N1 vaccine, at least enough for doctors, first responders and the armed forces.

That's sensible. Do we know how effective the h5n1 vaccine is, given that bird flu is so rare in humans to begin with?

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NotAnotherEmpire t1_j9vtck8 wrote

We don't "know know" because the infections are so rare and the virus is so dangerous. This is not a virus where one would do human challenge tests.

We do know what a successful flu vaccine match looks like though, and in animal tests (like the one linked) it shows what we want to see.

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The_RealKeyserSoze t1_j9uak8y wrote

We don't really stockpile flu vaccines because influenza changes and so older versions would not be very helpful. Instead we stockpile the raw materials and production capabilities for the vaccines. The traditional flu vaccine is made using chicken eggs infected with the virus so many countries have their own emergency supplies of chickens/eggs for this purpose.

Now that we also havecell based flu vaccines that don't require chicken eggs as well as future mRNA based flu vaccines that can be rapidly mass produced there will likely be a variety of of options for stockpiling/emergency preparation.

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xanthraxoid t1_j9uyz4e wrote

Emergency Chicken Stockpile is a combination of concepts I didn't expect to encounter today...

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