Cost-effectiveness of dog rabies vaccination programs in East Africa

Background Dog rabies annually causes 24,000–70,000 deaths globally. We built a spreadsheet tool, RabiesEcon, to aid public health officials to estimate the cost-effectiveness of dog rabies vaccination programs in East Africa. Methods RabiesEcon uses a mathematical model of dog-dog and dog-human rabies transmission to estimate dog rabies cases averted, the cost per human rabies death averted and cost per year of life gained (YLG) due to dog vaccination programs (US 2015 dollars). We used an East African human population of 1 million (approximately 2/3 living in urban setting, 1/3 rural). We considered, using data from the literature, three vaccination options; no vaccination, annual vaccination of 50% of dogs and 20% of dogs vaccinated semi-annually. We assessed 2 transmission scenarios: low (1.2 dogs infected per infectious dog) and high (1.7 dogs infected). We also examined the impact of annually vaccinating 70% of all dogs (World Health Organization recommendation for dog rabies elimination). Results Without dog vaccination, over 10 years there would a total of be approximately 44,000–65,000 rabid dogs and 2,100–2,900 human deaths. Annually vaccinating 50% of dogs results in 10-year reductions of 97% and 75% in rabid dogs (low and high transmissions scenarios, respectively), approximately 2,000–1,600 human deaths averted, and an undiscounted cost-effectiveness of $451-$385 per life saved. Semi-annual vaccination of 20% of dogs results in in 10-year reductions of 94% and 78% in rabid dogs, and approximately 2,000–1,900 human deaths averted, and cost $404-$305 per life saved. In the low transmission scenario, vaccinating either 50% or 70% of dogs eliminated dog rabies. Results were most sensitive to dog birth rate and the initial rate of dog-to-dog transmission (Ro). Conclusions Dog rabies vaccination programs can control, and potentially eliminate, dog rabies. The frequency and coverage of vaccination programs, along with the level of dog rabies transmission, can affect the cost-effectiveness of such programs. RabiesEcon can aid both the planning and assessment of dog rabies vaccination programs.
Author summary Dog rabies causes, globally, approximately 55,000 human deaths per year. Mass vaccination programs can control dog rabies. We built a spreadsheet-based tool, RabiesEcon, to aid public health officials in planning large-scale dog rabies vaccination programs. We used RabiesEcon to estimate the cost-effectiveness of dog rabies control programs in East Africa for a human population of one million (approximately 2/3 urban, 1/3 rural). We evaluated three different vaccination options: no vaccination, annual vaccination of 50% of dogs, and semi-annual vaccination of 20% of dogs. Over a 10-year period, no dog vaccination results in approximately 44,000–65,000 rabid dogs and 2,000 human deaths. Annually vaccinating 50% of dogs for 10 years resulted in approximately 42,000–48,000 fewer rabid dogs and approximately 2,000–1,600 fewer human deaths. These reductions cost approximately $450-$385 per life saved. Semi-annual vaccination of 20% of dogs for 10 years resulted in approximately 41,000–50,000 fewer rabid dogs and approximately 2,000–1,900 fewer human deaths. These reductions cost approximately $400–$300 per life. In certain scenarios, 70% of dogs vaccinated eliminated dog rabies. Dog rabies vaccination programs can control, and potentially eliminate, dog rabies.