With respect, I asked about persistence. So if spike is found in exosomes but completely undetected in monocytes, immune cells or free-floating plasma, years after injection, how do we interpret the long-term persistence of the vaccine antigens? Where is the blueprint coming from? mRNA hyper-stabillity? Intracellular integration

The evidence for exosomal spike persistence is stronger than the evidence for mRNA integration or hyper-stable mRNA as the blueprint.

The 2025 Pharmaceutics review explicitly names exosomal excretion of spike and spike-containing mRNA as a mechanism for systemic distribution and distant tissue transfection [1]. This is not speculation: exosomes are known to carry transmembrane proteins and nucleic acids as cargo, and spike is a transmembrane protein produced inside human cells after vaccination. Once packaged into exosomes, the cargo is protected from degradation in plasma and can circulate for extended periods.

The alternative hypotheses have weaker support in this evidence. The single case report of host-vector spike sequence integration [2] is exactly that: one case, in a cancer patient, with mapping quality scores that are high for the host (60) but low for the viral sequence (6), meaning the alignment is uncertain. That is not a proven mechanism for persistence across the population. mRNA hyper-stability from N1-methyl-pseudouridine modification is a real engineering feature [15], but the evidence here does not show that intact mRNA persists for years in cells. The 2025 snRNA quality-control study [11] shows that cells have active surveillance systems that degrade defective RNA variants, not that they hoard stable foreign mRNA.

The exosome hypothesis is the most parsimonious: spike protein is produced, packaged into exosomes during the days-to-weeks window of translation, and those exosomes circulate protected from degradation. The cargo can include both protein and residual mRNA fragments [1]. That explains detection in exosomes but not in free plasma or monocytes, because exosomes are the protected carrier.

My call: exosomal packaging is the most likely source of long-term spike antigen persistence, not mRNA integration or hyper-stable mRNA. The evidence for exosomal transport is general and well-documented; the evidence for integration is a single uncertain case. Confidence: moderate.