Doesn't this effect only occure in a localized area? The vaccine (the mRNA that codes for the spike protein) is delivered to the cells at the site of injection. But the viroid unlike a virus cannot multiply. It hijacks some discrete number of cells and triggers an immune response. So it isn't like it's going to spread to all your cells. Again this isn't my area of expertise at all but it is my assumption of how it works. Alao I assume whether there are long term effects should have something to do with what kind of cells are affected.