For example i don't have rabies, i haven't bitten by a cat or scratched and i just take anti rabies vaccine. is it bad? would that make me sick?

Common: The rabies vaccine is often used by those in the business of handling animals as a safety measure.They get the vaccine as part of their work, and repeat it every 2 years as long as they are in a high risk setting.Anyone can have individual allergic or intolerance reactions to components of a vaccine, but when given under proper conditions these can be identified & managed successfully.