Cost of dengue outbreaks: literature review and country case studies

Abstract

Background: Dengue disease surveillance and vector surveillance are presumed to detect dengue outbreaks at an early stage and to save--through early response activities--resources, and reduce the social and economic impact of outbreaks on individuals, health systems and economies. The aim of this study is to unveil evidence on the cost of dengue outbreaks.

Methods: Economic evidence on dengue outbreaks was gathered by conducting a literature review and collecting information on the costs of recent dengue outbreaks in 4 countries: Peru, Dominican Republic, Vietnam, and Indonesia. The literature review distinguished between costs of dengue illness including cost of dengue outbreaks, cost of interventions and cost-effectiveness of interventions.

Results: Seventeen publications on cost of dengue showed a large range of costs from 0.2 Million US$ in Venezuela to 135.2 Million US$ in Brazil. However, these figures were not standardized to make them comparable. Furthermore, dengue outbreak costs are calculated differently across the publications, and cost of dengue illness is used interchangeably with cost of dengue outbreaks. Only one paper from Australia analysed the resources saved through active dengue surveillance. Costs of vector control interventions have been reported in 4 studies, indicating that the costs of such interventions are lower than those of actual outbreaks. Nine papers focussed on the cost-effectiveness of dengue vaccines or dengue vector control; they do not provide any direct information on cost of dengue outbreaks, but their modelling methodologies could guide future research on cost-effectiveness of national surveillance systems.The country case studies--conducted in very different geographic and health system settings - unveiled rough estimates for 2011 outbreak costs of: 12 million US$ in Vietnam, 6.75 million US$ in Indonesia, 4.5 million US$ in Peru and 2.8 million US$ in Dominican Republic (all in 2012 US$). The proportions of the different cost components (vector control; surveillance; information, education and communication; direct medical and indirect costs), as percentage of total costs, differed across the respective countries. Resources used for dengue disease control and treatment were country specific.

Conclusions: The evidence so far collected further confirms the methodological challenges in this field: 1) to define technically dengue outbreaks (what do we measure?) and 2) to measure accurately the costs in prospective field studies (how do we measure?). Currently, consensus on the technical definition of an outbreak is sought through the International Research Consortium on Dengue Risk Assessment, Management and Surveillance (IDAMS). Best practice guidelines should be further developed, also to improve the quality and comparability of cost study findings. Modelling the costs of dengue outbreaks and validating these models through field studies should guide further research.

Figure 1

Cost components during dengue outbreaks in Vietnam. All in US$ of the year 2011; Vector control: 5,285,280 US$ (44%); Surveillance: 1,029,600 US$ (9%); IEC: 549,120 US$ (5%); Direct cost: 2,700,138 US$ (22%); Indirect cost: 2,447,000 US$ (20%).

Figure 2

Cost components during dengue outbreaks in Indonesia. All in US$ of the year 2011; Vector control: 465,676 US$ (7%); Surveillance: 13,722 US$ (0.2%); IEC: 2,927 US$ (0.04%); Direct cost: 3,288,168 US$ (48.7%); Indirect cost: 2,979,902 US$ (44%).

Figure 3

Cost components during dengue outbreaks in Peru. All in US$ of the year 2011; Vector control: 738,701 US$ (16%); Surveillance: 112,024 US$ (2%); IEC: 173,842 US$ (4%); Direct cost: 1,917,791 US$ (43%); Indirect cost: 1,569,102 US$ (35%).

Figure 4

Cost components during dengue outbreaks in Dominican Republic. All in US$ of the year 2011; Vector control: 9,165 US$ (0%); Surveillance: 2,550 US$ (0%); IEC: NA; Direct cost: 1,424,007 US$ (51%); Indirect cost: 1,367,047 US$ (49%).

Figure 5

Total cost components in percent estimated for a recent dengue outbreak in four countries. Direct costs include laboratory, technical services, drugs, consumables, fees and other resources. Indirect costs include loss of working hours. All in US$ of the year 2011; Vector control: 6,498 US$ (25%); Surveillance: 1,157 896 US$ (4%); IEC: 725, 889 (3%); Direct cost: 9,330,104 US$ (36%); Indirect cost: 8,363,051 US$ (32%).