Wasteful of his employer, not him.
```
Employer: We want you to take an extra and unnecessary vaccine dose, which you, as an RN, likely understand to be most-likely useless.
Employee: That's useless and unnecessary. No, I won't take it.
Employer: You're fired.
```
What kind of magical world do you think people live in where their employer doesn't hold a stupid amount of power over them?
I do not know any of the specifics of OP's situation, but it does sound reasonable.