There was no doubt that she was a danger to herself, but Klaus still felt his stomach turn at the feel of her delicate wrists, her thin body being crushed beneath his own. Sensing his hesitation, Vivianne sank her teeth into his forearm so deeply that he could hear the grinding sound of bone against bone. He gritted his own teeth and struck her hard across the cheek with his other fist, ignoring the tearing feeling as her clenched jaw ripped flesh away from his arm.

[...]

She was on her feet again in a flash, charging back toward him with her bloody hands outstretched, but he slammed the door between them and drove the bars home into their sockets. He felt the wood shudder as Vivianne’s body thrashed against it, and after a brief pause he felt the same thing again. His arm throbbed where she had bitten him. The flesh was already beginning to knit itself back together, but in the meantime it hurt like hell.

- The Originals: The Loss, Chapter 22