Vacunada literally means "vaccinated". It's a powerful and unexpected word to find in a fiery breakup anthem!
In the song, Shakira uses it as a brilliant metaphor. When she sings "estoy de ti vacunada" (I am vaccinated against you), she means she has become immune to her ex's lies and hurtful ways, a very creative way to declare her emotional strength and freedom.
Have you ever been in a relationship that felt more like a competition? In this song, Shakira is completely fed up with being in a love triangle. She tells her partner that one day it's about the other woman, and the next it's about her: "Es un día ella y otro día yo" (One day it's her and another day it's me). She's had enough of the drama and declares that she's leaving him to his "negocios sucios" (dirty business).
This isn't just a sad breakup song; it's an announcement. Shakira says she's become immune to his games, or "vacunada" (vaccinated) against him. The relationship has left her feeling numb, "como Monalisa / Sin llanto y sin sonrisa" (like the Mona Lisa / without tears and without a smile). She ends things with a final, brilliant line that gets to the heart of the problem: "el tango no es de tres" (the tango is not for three people). It's a powerful and dramatic exit!