In many people’s understanding, experiencing arm soreness after vaccination—so severe that the arm can hardly be lifted, sometimes persisting for weeks—is like a lottery: it all comes down to luck. With luck, the discomfort subsides in a couple of days; without it, one simply has to endure. We often attribute this to “individual physiological differences” or “strong immune responses.” Setting aside metaphysical explanations, this discussion focuses on the physical science perspective, specifically analyzing SIRVA. This is not only a matter of patient comfort but also directly affects vaccine immunogenicity and safety—and this study provides a precise anatomical explanation.
