When it comes to free-roaming dogs, oral rabies vaccination (ORV) may play a crucial role in the global fight against canine rabies and could revolutionise the progress towards the ‘Zero by 30’ global strategic plan. For the first time, and according to scientific literature, there is an oral rabies vaccine for dogs.

Regulatory approval of oral rabies vaccines and associated testing is cost-effective. A number of oral rabies vaccines, both attenuated or recombinant, have been developed and licensed for wildlife but not a single vaccine has yet claimed regulatory approval for dogs. However, if a vaccine is already licensed for wildlife, it may only take overcoming a few more hurdles to achieve this. As for wildlife, we need to ensure that an oral rabies vaccine, as well as the bait, are effective, safe and enticing for dogs. Most potential vaccine candidates have only been used experimentally in dogs, either in the laboratory or in the field. Only recently has a first oral rabies vaccine been reported to show high efficacy, immunogenicity and safety both under laboratory ^[1–4] and field conditions ^[5–8] and will apply for regulatory approval.

Safe and efficacious oral rabies vaccines respond to WOAH standards

Safe and efficacious vaccines, whether modified live or biotechnology derived, form a main pillar of the ORV programme for dogs. WOAH has established rigorous international standards for the efficacy and safety of oral rabies vaccines for both wildlife and dogs. With regard to dog vaccines, WOAH standards exceed the requirements for wildlife target species and include a human risk assessment that considers the probability of a person coming into contact with the vaccine, as well as the potential health impacts of that contact ^[9]. It is to be hoped that other vaccine manufacturers will follow the above example.

 Vaccinating the right dogs to save human lives

Canine rabies continues to take the lives of tens of thousands of people every year, particularly children in Africa and Asia. Here, free-roaming dogs play a key role in the transmission of rabies among other dogs. While there are increasing reports of the inadequacies of the parenteral vaccination approach, ORV may offer a powerful tool in achieving and maintaining adequate herd immunity in these subsets of susceptible dog populations ^[10,11]. This efficient way of reaching unhandleable dogs for vaccination can be a game changer if the goal of zero dog-mediated human rabies deaths by 2030 is to be achieved ^[12]. On behalf of the Tripartite, the United Against Rabies (UAR) Forum is currently working on new recommendations on ORV of dogs. So future efforts will hopefully lead to large-scale application of ORV as an integrated strategy for the control of dog-mediated rabies.

The Friedrich-Loeffler-Institut in Germany is a WOAH Reference Centre for rabies.

Photo: ©2022/Friedrich-Loeffler-Institute/Giulia Manzetti

References

1. Ortmann S., Kretzschmar A., Kaiser C., Lindner T., Freuling C.M., Schuster P., Müller T. & Vos A. (2018). – In Vivo Safety Studies With SPBN GASGAS in the Frame of Oral Vaccination of Foxes and Raccoon Dogs Against Rabies. Front. Vet. Sci., 5, 91, https://doi.org/10.3389/fvets.2018.00091.
2. Ortmann S., Vos A., Kretzschmar A., Walther N., Kaiser C., Freuling C.M., Lojkic I. & Müller T. (2018). – Safety studies with the oral rabies virus vaccine strain SPBN GASGAS in the small Indian mongoose (Herpestes auropunctatus). BMC Vet. Res., 14, 90, https://doi.org/10.1186/s12917-018-1417-0.
3. Head J.R., Vos A., Blanton J., Müller T., Chipman R., Pieracci E.G., Cleaton J. & Wallace R. (2019). – Environmental distribution of certain modified live-virus vaccines with a high safety profile presents a low-risk, high-reward to control zoonotic diseases. Sci. Rep., 9, 6783, https://doi.org/10.1038/s41598-019-42714-9.
4. Bobe K., Ortmann S., Kaiser C., Perez-Bravo D., Gethmann J., Kliemt J., Körner S., Theuß T., Lindner T., Freuling C., Müller T. & Vos A. (2023). – Efficacy of Oral Rabies Vaccine Baits Containing SPBN GASGAS in Domestic Dogs According to International Standards. Vaccines, 11, 307, https://doi.org/10.3390/vaccines11020307.
5. Leelahapongsathon K., Kasemsuwan S., Pinyopummintr T., Boodde O., Phawaphutayanchai P., Aiyara N., Bobe K., Vos A., Friedrichs V., Müller T., Freuling C.M. & Chanachai K. (2020). – Humoral Immune Response of Thai Dogs after Oral Vaccination against Rabies with the SPBN GASGAS Vaccine Strain. Vaccines, 8, 573, https://doi.org/10.3390/vaccines8040573.
6. Molini U., Hassel R., Ortmann S., Vos A., Loschke M., Shilongo A., Freuling C.M. & Müller T. (2021). – Immunogenicity of the Oral Rabies Vaccine Strain SPBN GASGAS in Dogs Under Field Settings in Namibia. Front. Vet. Sci., 8, 737250, https://doi.org/10.3389/fvets.2021.737250.
7. Chanachai K., Wongphruksasoong V., Vos A., Leelahapongsathon K., Tangwangvivat R., Sagarasaeranee O., Lekcharoen P., Trinuson P. & Kasemsuwan S. (2021). – Feasibility and Effectiveness Studies with Oral Vaccination of Free-Roaming Dogs against Rabies in Thailand. Viruses, 13, 571, https://doi.org/10.3390/v13040571.
8. Freuling C.M., Busch F., Vos A., Ortmann S., Lohr F., Hedimbi N., Peter J., Nelson H.A., Shoombe K., Shilongo A., Gorejena B., Kaholongo L., Khaiseb S., van der Westhuizen J., Dietze K., Geurtse G. & Müller T. (2022). – Oral rabies vaccination of dogs-Experiences from a field trial in Namibia. PLoS Neglect. Trop. Dis., 16, e0010422, https://doi.org/10.1371/journal.pntd.0010422.
9. World Organisation for Animal Health). – Chapter 3.1.17 – Rabies (Infection with Rabies virus and other Lyssaviruses). WOAH (Ed.) 2018 – Manual of Diagnostic Tests and Vaccines for Terrestrial Animals; pp 578–612.
10. Cliquet F., Guiot A.L., Aubert M., Robardet E., Rupprecht C.E. & Meslin F.X. (2018). – Oral vaccination of dogs: a well-studied and undervalued tool for achieving human and dog rabies elimination. Vet. Res., 49, 61, https://doi.org/10.1186/s13567-018-0554-6.
11. Wallace R.M., Cliquet F., Fehlner-Gardiner C., Fooks A.R., Sabeta C.T., Setién A.A., Tu C., Vuta V., Yakobson B., Yang D.-K., Brückner G., Freuling C.M., Knopf L., Metlin A., Pozzetti P., Suseno P.P., Shadomy S.V., Torres G., Vigilato M.A.N., Abela-Ridder B. & Müller T. (2020). – Role of Oral Rabies Vaccines in the Elimination of Dog-Mediated Human Rabies Deaths. Emerg. Infect. Dis., 26, e1-e9, https://doi.org/10.3201/eid2612.201266.
12. Abela-Ridder B., Balogh de K., Kessels J.A., Dieuzy-Labaye I. & Torres G. (2018). – Global rabies control: the role of international organisations and the Global Strategic Plan to eliminate dog-mediated human rabies. Rev. Sci. Tech., 37, 741–749, https://doi.org/10.20506/rst.37.2.2837.

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