Approaches to Refining Estimates of Global Burden and Economics of Dengue

Dengue presents a formidable and growing global economic and disease burden, with around half the world's population estimated to be at risk of infection. There is wide variation and substantial uncertainty in current estimates of dengue disease burden and, consequently, on economic burden estimates. Dengue disease varies across time, geography and persons affected. Variations in the transmission of four different viruses and interactions among vector density and host's immune status, age, pre-existing medical conditions, all contribute to the disease's complexity. This systematic review aims to identify and examine estimates of dengue disease burden and costs, discuss major sources of uncertainty, and suggest next steps to improve estimates. Economic analysis of dengue is mainly concerned with costs of illness, particularly in estimating total episodes of symptomatic dengue. However, national dengue disease reporting systems show a great diversity in design and implementation, hindering accurate global estimates of dengue episodes and country comparisons. A combination of immediate, short-, and long-term strategies could substantially improve estimates of disease and, consequently, of economic burden of dengue. Suggestions for immediate implementation include refining analysis of currently available data to adjust reported episodes and expanding data collection in empirical studies, such as documenting the number of ambulatory visits before and after hospitalization and including breakdowns by age. Short-term recommendations include merging multiple data sources, such as cohort and surveillance data to evaluate the accuracy of reporting rates (by health sector, treatment, severity, etc.), and using covariates to extrapolate dengue incidence to locations with no or limited reporting. Long-term efforts aim at strengthening capacity to document dengue transmission using serological methods to systematically analyze and relate to epidemiologic data. As promising tools for diagnosis, vaccination, vector control, and treatment are being developed, these recommended steps should improve objective, systematic measures of dengue burden to strengthen health policy decisions.Author Summary: Dengue is the most common mosquito-transmitted viral disease. It represents a formidable public health problem that is expanding in both infection rates and geographical range. Fortunately, vaccines, improved diagnostics, innovative vector control approaches, and other disease control methods are under development. Despite the importance of dengue, there is substantial uncertainty about the magnitude of the disease burden and economic cost of dengue, particularly in the number of symptomatic dengue infections. There is substantial variation in national reporting systems for dengue, which hinders accurate estimates of total cases and, therefore, of economic burden. Here we suggest a combination of immediate, short-term, and longer term strategies to address this knowledge gap. Immediate strategies include, for example, documenting the number of ambulatory visits before and after hospitalization. Short-term recommendations include merging multiple data sources, such as cohort and surveillance data to improve estimates of dengue incidence. Long-term efforts include increasing the collection and analysis of seroprevalence and economic data, use of enhanced surveillance (e.g., use of incentives to improve reporting, include private sector sentinel sites). Implementing these steps would give policy makers more reliable, systematic data for strengthening and refining policies about the application and financing of new technologies to control dengue.