Fentanyl (and the derivative the vaccine works on) have very short half-lives, which is ideal for _minimal_ dosing during surgery. Any drug that lengthens the QT interval, or fucks with the S wave will bring about catastrophic heart failure in people with conduction channel issues. The only time alternative anesthetics are given to me for example is to induce heart failure in order to test new leads.

I find the idea of a vaccine that makes therapeutic drugs fail to work quite scary personally.