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Comment by lfuller | Hacker News Reader

One question I have about mRNA vaccines that I haven't been able to find the answer to through my own searching: how is the mRNA delivered to the cell?

All the articles I read say that the mRNA is "taken up by the cell", but what is the mechanism? Do cells naturally just absorb free-floating mRNA? Or is a modified virus used to inject the mRNA?

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John Campbell talks about that here in a digestible way: https://youtu.be/smm_ZvJqJk4?t=438

Very very simplified: Basically, you have a blob of fat that the mRNA sits in. The fat sticks to the cell, merges with the cell membrane and the mRNA pokes into the cell. It's not a modified virus, it's a much simpler structure but it has a similar mechanism. It's much simpler in that it can't replicate itself or do much else. It's literally just the code for a protein that's found on the surface of the covid virus, in a blob of fat.

That's for the BioNTech/Pfizer vaccine. Other vaccines, such as the Oxford/AstraZeneca one do use a modified virus.

So no spike protein needed?

Safe to assume that in time these will evolve into new forms of fat-embeded rna virus which no living being has immunity to?

No, they won't. They can't survive for long enough inside the body, and are even less durable outside.

The mRNA contains the spike protein or at least a sufficient part of it for the immune system to recognize, as well as other genes.

In both the Moderna and Pfizer-BioNTech vaccines the RNA is encapsulated in “lipid nanoparticles”. These microscopic droplets of oily liquid — about 0.1 micron in diameter — enclose and protect the fragile genetic instructions as they are manufactured, transported and finally injected into people. https://archive.is/6dxTg

So it's naked mRNA wrapped in oil, basically?

“The lipid nanoparticles have some adjuvant activity, providing a little inflammation with the vaccination that helps the immune system to make antibodies and T-cells that target the Sars-Cov-2 virus,”

Itchy oil, then.

https://www.acsh.org/news/2020/10/21/how-pfizers-rna-vaccine...

Essentially the mRNA is packaged into a lipid, which the body's cells can uptake thru its phospholipid bilayer

It appears there are a few different approaches, described here:

https://en.wikipedia.org/wiki/RNA_vaccine#Delivery

Viral vectors were the ones I was familiar with. I am not sure which one the Pfizer vax uses, however.

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