Imovax Rabies; Rabavert; Descriptions. Rabies vaccine is an active immunizing agent used to prevent infection caused by the rabies virus. The vaccine works by causing your body to produce its own protection (antibodies) against the rabies virus. Rabies vaccine is used in two ways. Rabies vaccine is given to persons who have been exposed (e.g., by a bite, scratch, or lick) to an animal that is known, or thought, to have rabies. This is called post-exposure prophylaxis. Rabies vaccine may also be given ahead of time to persons who have a high risk of getting infected with rabies virus.