Role of Oral Rabies Vaccination in Dogs in the Elimination of Dog-Mediated Human Rabies Deaths
The mass vaccination of dogs is a proven tool for rabies prevention. Besides parenteral delivery of inactivated vaccines, over the past several decades, several self-replicating biologics, including modified-live, attenuated and recombinant viruses, have been evaluated for the oral vaccination of dogs against rabies. Vaccines are included within an attractive bait for oral consumption by free-ranging dogs. Due to the high affinity between dogs and humans, such biologics intended for oral vaccination of dogs (OVD) need to be efficacious as well as safe. Baits should be preferentially attractive to dogs and not to non-target species. Although many different types have been evaluated successfully, no universal bait has been identified to date. Moreover, high bait acceptance does not necessarily mean that vaccine efficacy and programmatic success is predictable. The use of OVD in the laboratory and field has demonstrated the safety and utility of this technology. Within a One Health context, OVD should be considered as part of a holistic plan for the global elimination of canine rabies. Barring a few countries, rabies is endemic in both humans and animals in most countries in the Asia and Pacific Region, with over 95% of human rabies cases associated with dog bites. For the effective control and elimination of dog-mediated rabies, a minimum of 70% vaccine coverage in susceptible dog populations is needed.
However, in many rabies-endemic countries in the region, owing to substantial numbers of free-roaming dogs that are difficult to catch for catch-vaccinate-release vaccination, countries do not achieve the required vaccination coverage. Oral rabies vaccines (ORVs) have been used successfully in eliminating sylvatic rabies from the wildlife reservoirs (red foxes, raccoons, etc.) in North America and Europe.
Although there are currently no examples of use of ORVs as part of the official dog-mediated rabies elimination programmes, research studies are currently underway in many countries focusing on the application of ORVs as a tool in complementing parenteral vaccination in dogs. There is clear interest from countries in the region to learn and understand more about ORVs and their use in complementing dog rabies vaccination.
How health experts can improve oral rabies vaccine use
To further explore the use of oral rabies vaccines (ORV) in dogs and make sure it is done safely, health experts worldwide should work in the following areas:
Safety Evaluation: Since oral rabies vaccine products contain a weakened version of live viruses, they need to be thoroughly evaluated for safety – for humans to handle and give out, and for animals to eat.
WHO and OIE have developed guidance and a report on how this can be done. Furthermore, a global formal vaccine review process could help to increase confidence regarding using these oral vaccine products.
Central Licensure: Not every country has a veterinary vaccine licensure process. And achieving licensure in every country could significantly delay rabies elimination. Entities such as the European Medicines Institute should consider recognizing regional veterinary vaccine licensures to reduce barriers to use of safe and effective oral rabies vaccines.
Bait Development: There is evidence that dogs may prefer different bait flavors based on what they typically eat, which can vary by where they live. Groups implementing use of ORV in dogs need to continue to examine which types of baits dogs most like to eat and ensure that these flavors can be mass produced.
Resource Allocation: Oral rabies vaccines are likely to cost more than traditional “shots.” Oral vaccines must be used appropriately, and with proper planning, to ensure that they are as effective as possible.
Education: Since oral rabies vaccines are a new product for dogs, international organizations will need to develop new educational programs to help vaccinators and owners understand the benefits of these new vaccines and how they can be used to eliminate rabies cases linked to dogs.
ORV can play a vital role in the fight against rabies and offers a new tool to help save lives now and reach the goal of eliminating human rabies deaths caused by dogs by 2030.
ORAL VACCINATION OF DOGS AGAINST RABIES
SAFETY AND EFFICACY OF USING ORAL RABIES VACCINES IN DOGS FROM FIELD STUDIES IN THAILAND
Dr Nirbhay Kumar Singh , Department of veterinary Anatomy
Bihar veterinary college
source-on request
