This should be discussed more but sadly, it's so boring next to all of the other Vax theories that it gets over looked. I've personally witnessed people getting their jabs in front of me and I have yet to see a nurse pull back on the plunger to see if they hit a vein. Which is what is supposed to be done. This is completely anecdotal and I'm sure some do, but I think this is a major contributer to the side effects.