PHFI/RCZI Advocates for One Health approach to Cost Effectively Control Rabies

Rabies claims more than 59,000 lives around the world every year. Over 20,000 of these deaths take place in India, where most victims are children in rural areas and people from marginalised sections of society. Canine vaccination is a possible solution with potential to curb rabies transmission to humans. It has worked remarkably in settings like the United States and Great Britain, where it helped eliminate canine rabies. In Western Europe, South America and regions of sub-Saharan Africa and Asia, it has helped control rabies significantly. However, in India it has not gained traction. This is because canine vaccination has been clubbed with animal birth control as ABC-AR which has been found to be prohibitive in cost compared to canine vaccination alone..

Furthermore, cost-effectiveness of canine rabies vaccination has not even been evaluated for India. Despite the high prioritisation of rabies control by zoonotic disease experts in India, policymakers have been reluctant to implement widespread canine rabies interventions without conducting any sort of an assessment of the balance between expenditure and effectiveness. Campaigns of combined stray canine vaccination and sterilisation have been advocated by the Animal Welfare Board of India as a humane intervention to control rabies and some of these campaigns have been effective in a few cities. However, this is still sporadic and not a widespread initiative.

Despite the increased priority being accorded to rabies which is now classified as a priority disease by WHO, a disconnect among research and policy persists. PHFI/ RCZI through their research efforts tried to bridge this gap by identifying information needs and gaps for conducting assessments of impact of rabies and its interventions in India. Supported by a Grand Challenge award from the Bill and Melinda Gates Foundation, researchers from PHFI, LSHTM & Yale came together in 2012 to develop a One Health framework to assess impacts of zoonoses and their interventions in Tamil Nadu. A national stakeholder meeting was held in January 2015 on rabies assessment. This was followed by another multi-stakeholder meeting in September, 2015. A Costs Analysis of a Population Level Rabies Control Programme in Tamil Nadu, India was conducted and a Test Case for ‘One Health’ Approach mooted. A policy brief was brought out earlier this year suggesting dog vaccination as an essential intervention for rabies control, using the Tamil Nadu experience.

Case study of cost-effective canine interventions in Tamil Nadu with potential for replication
Meanwhile, the work done by researchers from PHFI/RCZI who developed a data-driven rabies transmission model fit to human rabies autopsy data and human rabies surveillance data from Tamil Nadu has been discussed in detail in the PNAS 2016 edition under the title, “One Health approach to cost effective rabies control in India”.

Currently, rabies control in Tamil Nadu involves post exposure vaccination of humans after dog bites, whereas potential supplemental approaches include canine vaccination and sterilisation. The study team presented a cost-effectiveness evaluation of rabies control strategies for Tamil Nadu , predicting the impact of exclusive vaccination strategies as well as combined strategies of canine vaccination and sterilisation. To evaluate these strategies, they integrated a model of rabies transmission and canine demography within a framework of cost-effectiveness analysis parameterised by data from Tamil Nadu. They took into account both rabies mortality and dog bite morbidity in determining outcomes of disability-adjusted life-years (DALYs), a measure of health impact that ranges from zero (no health impact) to one (an entire year lost to death).

Applying a WHO criteria for cost effectiveness, which defined strategies as “very cost-effective” or “cost-effective” when they confer health benefits at a cost per DALY that is less than the per capita gross domestic product (GDP) of a country or three times the per capita GDP, respectively. Recognising that organisations and policymakers would prefer to apply cost-effectiveness thresholds that differ from WHO standards, they also evaluated the optimal strategy across a variety of thresholds.

Vaccinating stray dogs can reduce human rabies deaths by 70%
The study team evaluated the effectiveness and cost-effectiveness of canine-focused rabies control programmes as an approach for reducing human rabies

According to the study, a highly feasible strategy was suggested, namely to focus on stray dogs, vaccinating as few as 7% annually and thereby cost-effectively reducing human rabies deaths by 70% within 5 years. A modest expansion to vaccinating 13% of stray dogs could further cost-effectively reduce human rabies by almost 90%. An annual vaccination target of 200,000 stray dogs corresponds to ∼13% of the canine population, which is highly feasible to implement in Tamil Nadu and other settings in India. If owners are willing to bring dogs to central point campaigns at double the rate that campaign teams can capture strays, expanded annual targets become even more cost-effective.

Stray capture canine vaccination at an annual target of 200,000 dogs or ∼13% coverage is estimated to cost $2.68 ($2.68–$2.68) million in the first year. A combined strategy of stray canine vaccination and sterilization of both females and males with an annual target of 200,000 dogs is estimated to cost $5.40 ($5.39–$5.40) million in year 1. Thus canine vaccination was more efficient than combined vaccination and sterilisation.

Need for better coordination between sectors and adoption of a One Health approach
Despite a commitment to PEP, rabies will continue to threaten human life if unabated in canine populations. Coordination between different sectors of the state government will be fundamental to the successful control of rabies not just in the state of Tamil Nadu but in the country as a while. Canine interventions will require participation, expertise, and resources of the Department of Animal Husbandry Dairying & Fisheries and the Animal Welfare Board of India, neither of which have a mandate or funding to address human health challenges.

The study concluded with the conviction that human rabies can be virtually eliminated with a much more moderate investment than anticipated. The successful implementation of canine vaccination in Tamil Nadu can serve as an example of cost-effective rabies control for similar settings within and beyond India.