Evaluation of long-term protective efficacy of rabies vaccines in dogs

Rabies is a fatal encephalitis caused by rabies virus. It causes more than 59,000 human deaths worldwide annually. Rabies vaccination can prevent the development of rabies in humans and animals. In dogs, booster vaccination is administered annually or triennially, as per local law or the vaccines used. To evaluate the long-term efficacy of current rabies vaccines, beagles vaccinated 6 and 8 years ago, were challenged with a virulent rabies virus. Blood and lymph node aspirates were collected for the analysis of immune responses. It was found that 80% of the six-year vaccinated dogs survived with the induction of high levels of virus-neutralizing antibodies (VNA), whereas 80% of the eight-year vaccinated dogs and all of the non-vaccinated dogs succumbed to rabies. Also, six-year vaccinated dogs induced better cellular immune responses than other dogs. These results indicate that a single shot of rabies vaccine can protect dogs for up to six years.