Investigating the effectiveness of oral rabies vaccination in the control of canine and human rabies

Global Animal Health Tanzania, Arusha

Investigators

Abstract

PROJECT SUMMARY Rabies has the highest case fatality rate of any known human infectious disease and kills around 60,000 people annually. Nearly all of these deaths (99%) occur in Africa and Asia and are due to canine rabies. While human rabies can be prevented with post-exposure prophylaxis, the intervention is costly and often not available in remote communities where it is needed. Targeting control efforts at the reservoir host through mass dog vaccination is an effective approach. Parenteral vaccination is the conventional method of choice for dealing with dog-mediated rabies in many rabies-endemic countries. This approach has proven to be effective in regions where responsible dog ownership is practiced. The level of responsible dog ownership in Africa is low. While the majority of dogs have some form of affiliation with households, a significant proportion of dogs roam freely, presenting a substantial public health concern for the maintenance and spread of rabies to humans. Reliance upon parenteral vaccination, therefore, can be inadequate in these settings. Oral rabies vaccination (ORV), which has been successfully used in rabies virus elimination in wildlife populations, offers an alternative way to reach dogs that are inaccessible for parenteral vaccination. The immunogenicity of ORV in dogs has been evaluated in laboratory and field conditions and vaccines delivered this way have been shown to be safe, immunogenic and efficacious. However, to date, there have been no studies investigating the application of ORV in rural settings and at scale. The proposed study aims to: First, determine if the oral rabies vaccine is thermotolerant following storage in Zeepot up to 7 days. We hypothesize that the oral vaccine will remain potent following storage in Zeepot for limited period of time. Second, through a randomized controlled trial (RCT), compare the coverage achieved through an enhanced (parenteral plus oral) vaccination strategy against the standard, parenteral vaccination-only approach. We hypothesize that supplementing parenteral vaccination with ORV will lead to increased coverage compared to the conventional parenteral-only strategy. Third, we will use the coverage output from the RCT to model the impact that the anticipated increased coverage achieved through enhanced vaccination has on public health outcomes. We hypothesize that the implementation of the enhanced vaccination strategy will lead to a reduction in human dog bite injuries and human rabies cases compared to the standard parenteral-only intervention. Fourth, carry out cost-effectiveness and benefit-cost analyses to assess the overall public health benefits of the enhanced vaccination strategy. We hypothesize that the cost-effectiveness analysis will demonstrate that the implementation of the enhanced vaccination strategy will be the more cost-effective (lower cost) for a given coverage goal, thus reducing the economic cost burden of mitigating human rabies through mass dog vaccination compared to the parenteral-only strategy. Contact PD/PI: Lugelo, Ahmed Project Summary/