Field trials of a very potent rabies DNA vaccine which induced long lasting virus neutralizing antibodies and protection in dogs in experimental conditions.

Kinetics of antibody responses and protection against rabies were investigated after injection of a single dose of rabies DNA vaccine and compared to those induced by one or two injections of cell culture-derived vaccine in dogs issued from the common local breed and reared in experimental conditions. Rabies DNA vaccine administered intradermally by a jet injector in the inner face of the ear was by far more efficient in inducing long lasting high titers of virus neutralizing antibodies compared to cell culture vaccine Rabisin administered either subcutaneously or intramuscularly. Four years after vaccine administration of either DNA or cell culture-derived rabies vaccines, full protection against a rabies peripheral challenge was achieved. Vaccine trials targeting dogs living in field conditions in Tunisia further established that rabies DNA-based vaccination induced a stronger induction of virus neutralizing antibodies compared to Rabisin. This report shows for the first time that DNA vaccination could be more efficient under experimental or field conditions in large size mammals than the best commercially available cell culture-derived vaccine. This improvement will hopefully allow a better rabies control in developing countries by using a more efficient vaccination with fewer doses and targeting all categories of dogs.