I came to say precisely this.

The standard hp for a regular human, which for the setting is probably in better shape than the office honed bodies of today, to be incapacitated for combat and eventually die is about 4 (depending on edition).

There is maybe one way a trained human could perform a combat biting attack that would render someone unable to fight back, which is a bite to crush the wind pipe, and with all anatomical protection in place, it seems unfeasible even if they would have the jaw strength for it.