It is conducted by vaccinating two groups of mice twice, 7 days apart, with dilution of a reference vaccine and the vaccine under test. Seven days after the last vaccination, the immunized mice and a control group of mice are challenged with the challenge virus strain (CVS) of fixed rabies virus. The mice are observed for 14 days and the median effective dose (ED50) of the reference and the test vaccine is determined, based on the number of survivors. The relative potency of the test vaccine is then calculated by comparing the ED50 of the test vaccine with that of the reference vaccine.
Minimum potency requirements: The relative potency of rabies vaccine is determined using a recognized rabies reference vaccine and the batch of rabies vaccine used in a valid vaccination challenge test in target species.