they give you the shot into the muscle of your arm, not into a vein. Why is this, the vaccine is not supposed to go into your bloodstream. If it does, that is when it causes heart problems and clots. Pretty obvious to me. You do have veins in your upper arm of course so it can get in there. I think they should have some other way of administering it so it doesn't get into the blood stream. But they want to let untrained clerks working at drugstores to give the shot, probably to make it easier. Only highly trained infectious disease doctors should give the shot IMO.