alt Hacker NewsDo we have any studies that show this fast clearance? From what I understand at least one of them used a pseudo-uradine that there isn't an efficient direct metabolic pathway to process, which was kind of the whole point. The idea being it would circulate longer and be "more effective"
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Numerous studies have found vax-derived spike persisting for months and even years after vaccination, giving rise to concerns expression of spike can continue long after the claimed 24-48 hours.
A recent study found spike protein persisting for 17 months in the cerebral arteries of stroke victims. [1]
[1] https://www.sciencedirect.com/science/article/pii/S096758682...
That's right, they use N1-Methylpseudouridine instead of uridine (the nucleoside contained in uracil, which is the U in mRNA sequences) to last a bit longer (but not forever) and to avoid triggering immune reactions to the mRNA itself (the immune system can detect foreign mRNA).
Certainly the vaccine's mRNA sequence breaks down into separate nucleotides. If it did not, continued production of the antigens would cause a chronic immune reaction and/or immune exhaustion that would make the vaccine ineffective.
I don't know what happens to the N1-Methylpseudouridine though. That's an interesting question.
The uridine modification was intended to reduce immunogenicity of mRNA - some of our immune cells have pattern-seeking receptors in the TLR family that recognize ssRNA and dsRNA. The presence of modified uridines throws this pattern recognition off. (https://doi.org/10.1016/j.jconrel.2015.08.051)
The modifications to increase mRNA half-life concerned mostly the caps and poly(A) tail. But even with those the persistence was in the range of days (sort of depending on how sensitive a method you picked).