>Don't people have different immune systems, thus even if you gave them exactly the same 'bits' that wouldn't result in differing outcomes?

Essentially, there is a region of DNA called the Major histocompatibility complex that is, er, the Genetic equivilent of a computer's PRNG, except it actually does shuffle DNA around (twins aren't even identical), so it's true RNG, but static after conception. This random DNA is used by the immune system to make basically every kind of antigen-receptor possible (the thing that does the sensing/binding for a white blood cell). During development, there is a mechanism by which if antigens match, it's assumed to be matching to "self" and it gets whitelisted and not made again. Eventually you are left with a library of antigen-receptors that don't bind to anything inside you - the correct state for a mature white blood cell. Then you are born, and the immune system kicks in and starts recognising all new antigens of these antigen-receptors as foriegn, and long story short when that happens the white blood cell will both divide and suicidally attack anything it's receptors bind too.

So all of the antigen-receptor based part of the immune system is different between people, giving us group diversity, even in a small isolated family of individuals. However. The miRNA suppression complex and other DNA/RNA based facets of your immune system - some of which i probably don't even know about, but I know of at least 2 - do not work in this way. They work at the DNA/RNA sequence level, in a non-analog way. A digital way. They are triggered by the detection of a forigen sequences, and stop infection before any viral protein is produced. By comparison, these digital parts of our immune system counteract the bulk of our protection to viruses. While the analog antigen-receptor method will work for poisons, viruses, moulds, worms, cancer, etc, the digital immune system is much faster and much more energy efficient, and essentially once your cells are updated (which we assume they each do individually but maybe there is co-ordination) they simply can not be hijacked by that kind of virus. No amount of viral load will overcome the cellular innate immune system, that is constantly having to supress retrovirals, let alone exogenus fractions of a fraction. It's the information in a virus that is the problem.

>If DIY is viable then it would be trivial to forge ID and/or make something communicable that screws up the ID. You can presumably write and over write fragments as easily as the initial write.

I hadn't considered that. Actually a lot of the older genetic tools in the toolkit only let you "insert", and even then only in a pre-determined place. CRISPR allows in-place editing, but even then it's not so easy/pragmatic as one would hope. More importantly, if I wanted to barcode you I would use technology out of your reach to do it, or to load it up, or whatever. You see this a lot with DRM. The point being, if they have a cool trick to hide DNA/RNA from sequencing machines - and to be honest that is as trivial as using synthetic bases and/or paying off the sequencing monopoly that is Illumina - then it's possible we won't be able to find the barcode for a while, and when we do we might not have the technology to get our new stuff to where it got it's stuff back when you were vaccinated. I'd imagine they write to your white bloodcell's genome in a sort of hap-hazard way, which is probably what is suppressing the immune system of some older people, as some of those cells might die if the barcode is inserted into the wrong region. But if the white bloodcells survive then they will eventually have daughter cells that will carry the insertion onwards, and it will remain in your blood and sweat. If that's the case, it's all doable with modern technology developed in the last 5 years, but targeted removal of the sequence will be out of reach for at least 50 years.

>What you want is a unique identifier that never changes. You can hang everything else off that one variable. 

Yeah, actually, that sounds far more likely. And also totally doable with synthetically made DNA/RNA, it's done all the time to basically barcode individual cells in a suspension of cells before sequencing them all at once, and there is literally billions of cells. You assumed it would be expensive, and I don't blame you, but it's actually really cheap and has been par for the course for about 4 years now. It's as easy as having the synthesis reaction simply extend the DNA with a random base in solution, so it basically doesn't cost anything extra to write random junk than it costs to write a specific base. What costs extra is very long sequences, over 100 letters long. But with just 20 letters i can usually target a specific portion of a 3-billion-base human genome. So a per-citizen tag per-vaccine is no problem at all. All automatable. Actually the automatable was only invented in the past 3 years hahah. My poor arms.

Why do you think the DNA sequence couldn't be different from batch to batch? 

Nothing about what I described would be illegal, per se. It's their vaccine, if they want small but specific change from batch to batch, i'm not sure that would be illegal. Police will probably use the immunological profile of suspects regardless of whether they are in on it or not. Intentional or not, this wasn't a problem with previous kinds of vaccine.

wat. mRNA is ssRNA.

I have no idea, but I can take a guess. 1) Because crime scenes will have more information left in them. We can't tell your age all that easily from a blood sample, but if your vaccinated with something suitable for your age range...

and 2) obviously being the spike protein being present on your cell surfaces is like an interacellular backdoor. But that isn't my area of expertiese at all, just pure speculation on my part :)

Ah OK i understand the confusion, and it's from an oversimplification of how the vaccine works. While both the DNA and RNA vaccines are said to produce spike proteins that ultimately present on the surface of the host cell, triggering an immune response, there is also the viral DNA/RNA immune system, sometimes described as the RISC: How Drosha and Dicer work in RNA interference - YouTube

This works with both double-stranded and single-stranded RNA, but the system seems to be much more aggressive against double-stranded, which would make sense as since humans don't make dsRNA very often, while their are whole classes of virus dedicated to it. It's way less "self", because self RNA has special sequences (poly-A) and is decorated in special proteins (CAP) that it acquired due to being made at the right place at the right time. Kind of like a hallway pass.

I don't know if the Moderna or Pfizer vaccines, which are RNA, are ssRNA or dsRNA, but suffice to say they will absoluely kick off the immune response. To my knowledge it would be unfathomibly hard to sneak synthetic DNA/RNA past the RISC (and there are homologs for DNA by the way - DNA is supposed to be in the nucleus only, and decorated in all sorts of shit). If it can be done, it can't be done on the cheap, which is what these new class of vaccines are supposed to provide.

This system is not some abstract complex that doesn't play a role, it is THE method by which the cell protect itself from viral attacks, at the front-line. The presentation of the spike protein on the surface of the cell is the white flag of surrender, as it will kick off necrosis through immune recognition for sure. The RISC and similar pathways also hold back all retrovirals, so it's a constant background thing going on. Also present in germline cells, just FWIW.

But even if the RISC and similar pathways are not involved at all, the digital nature of the vaccine in that all of our cells will present the exact same spike protein in pre-packaged form for the immune system to digest, be it RNA or DNA as the route, creates a situation where that spike protein could be cheaply designed to be reliably and specifically different from batch of vaccine to the next, as a tag, with no obvious effect on the efficacy of the vaccine. The modification of an internal fold for example would be all that is needed, and now that person will express that information in their blood for as long as they stay immunised.