Oral rabies vaccine: a new strategy in the fight against rabies deaths

Did you know dogs cause nearly 59,000 annual human rabies deaths worldwide?

Major partners¹ have pledged to eliminate rabies spread by dogs. Their goal is to reach zero human deaths by 2030. Risk of rabies is especially high in countries with large stray dog populations or where the community, rather than a single owner, cares for dogs.

“Free-roaming dogs have played a major role in spreading rabies among animal and human populations in Thailand and other countries in the region for decades. Vaccinating these dogs with shots takes tremendous effort. Without any innovative tools to vaccinate free-roaming dogs, rabies elimination is difficult to achieve.” Karoon Chanachai, formerly Department of Livestock Development (DLD) and now regional animal health advisor for the U.S. Agency for International Development’s Regional Development Mission for Asia.

Because dog bites cause most of rabies deaths – more than 9 of every 10 cases – keeping dogs from getting rabies is the most important strategy to prevent human rabies deaths. We can help prevent rabies deaths in people by routinely vaccinating dogs against rabies.

To get rid of rabies in the community, we need to vaccinate 7 out of every 10 dogs.

Current rabies vaccination programs for dogs rely on the use of injectable shots. This method for protecting dogs from rabies in low-income countries can be tricky since many dogs have not been to a veterinarian and may not be accustomed to close interactions with people.

A newer method – giving dogs oral vaccine – is gaining traction as a safe and effective alternative.

The World Health Organization (WHO) and World Organisation for Animal Health (OIE) support the effective and safe use of oral rabies vaccines for dogs.

Getting the dogs to ‘eat’ a rabies vaccine bait is much quicker, easier and more practical than capturing them in nets and giving them rabies shots. It also saves money because more dogs can get vaccinated each day.

“It takes months to train a team of physically fit people to catch hard-to-reach dogs using nets for rabies shots. These same dogs can be vaccinated using oral vaccines by people after a few hours of training in how to spread the bait. This efficient way of reaching previously unhandleable dogs for vaccination is a game changer. It could/will drastically improve rabies control in many parts of the world where it’s still a major problem.” Andy Gibson, director of strategic research for Mission Rabies.

 

ORV IN THAILAND

“Thailand applies an oral vaccine in its free-roaming dog population. Working with partners, we identified the most appropriate bait for Thai free-roaming dogs. We worked with five cities/towns to roll out oral rabies vaccination in their areas in 2020, vaccinating almost 2,000 free-roaming dogs. We achieved 65% of vaccination coverage in the free-roaming dog population in these areas. All parties agreed that this tool is feasible and practical to increase vaccination coverage in inaccessible dog populations. More importantly, there have been no rabies outbreaks reported in free-roaming dogs in any of these five municipalities since oral vaccination was conducted. We will be scaling up oral rabies vaccination in free-roaming dogs in 2021 to complement rabies vaccine shots.” Karoon Chanachai, regional animal health advisor for the U.S. Agency for International Development’s Regional Development Mission for Asia.

 

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. (Photos by Pierre Dilius/www.who.int)

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¹The World Health Organization (WHO), World Organisation for Animal Health (OIE), Food and Agriculture Organization of the United Nations (FAO) and Global Alliance for Rabies Control (GARC) comprise United Against Rabies (UAR)