This is a logical method of accomplishing a method of generating unique signals;

HLAs are what cause you to reject foreign tissue such as a transplant; So let us assume that a batch is somewhat unique, combining it with the HLA would make it unique;

Further, it has already been shown that the vax interacts with Transferrin (iron) a critical protein, which would provide all the building blocks needed for micro antennas;

Inevitably this information will leak out as they will start to use these IDs in daily life, maybe the reason they are pushing to get everyone vaxxed quick;