ABSTRACT This article surveys Shakespeare’s biopolitical thought, with a focus on the semantic feature of “inoculat[ion]” in Hamlet. Today, the word “inoculation” means a way to produce artificial immunity by inserting a pathogenic material taken from an external entity through a small incision. This medical procedure, widely practiced in the eighteenth century, is called inoculation because it was like grafting—mixing one body with another. By using “inoculat[ion]” as a rhetorical device, Hamlet explores the politics of immunity before the dawn of modern immunology. Shakespeare’s work negotiates legal and medical thoughts on immunity: in particular, Hamlet is an intriguing text because it balances two different features of immunity, signifying at once juridical exception (as a signature of sovereign authority) and the negative protection of a body (through the metaphor of corpus politicum). Like the metaphor of inoculation (i.e. grafting), a practice that needs the other’s body, Hamlet shows that the body politic can be secured only when the realm elects the same invading foreign entity. In Shakespeare’s early modern imagination, immunity is not a strict boundary between self and non-self; rather, it is a much more negotiable boundary open to alterity and creaturely existences.