[Humane endpoints as a replacement for the estimation of lethality rates in the potency testing of rabies vaccines]

Vaccines are successfully used to prevent rabies infections in humans and animals. The quality requirements for these products are high. After licensing it is still necessary for batch release to perform animal challenge tests to demonstrate the potency of the vaccines. In these experiments it is registered how many animals in the immunised groups die or show symptoms of rabies within a defined time frame. An ECVAM working group has examined whether clinical signs can be used in challenge tests for vaccine control to replace lethality as criterion. The severe distress and the typical signs of the disease made the rabies infection a promising example for this study. Clinical signs, body temperature and body weight were the criteria used to define humane endpoints. It could be shown, that the reduction of body weight and the appearance of typical clinical signs are suitable to define humane endpoints. Pain and distress could be considerably reduced by the implementation of these criteria in to the legal requirements for potency tests of rabies vaccines.