Thank you and I appreciate your comment. Please correct me if I misunderstood what you mean, but immune memory refers to pre-existing adaptive immune cells (i.e., the B-cells and T-cells) that recognize a specific antigen (like a virus’s protein).

Without immune memory, these immune cells that recognize and neutralize (or attack) the antigen have to be made from scratch, which can up to a week. With immune memory, this step can be skipped since these immune cells have already been made (from vaccination).

So, immune memory doesn’t get out, because it’s already there. I hope that’s clear, but let me know again if it’s not.