The costs of monitoring trachoma elimination: Impact, surveillance, and trachomatous trichiasis (TT)-only surveys

Background: Although trachoma causes more cases of preventable blindness than any other infectious disease, a combination of strategies is reducing its global prevalence. As a district moves toward eliminating trachoma as a public health problem, national programs conduct trachoma impact surveys (TIS) to assess whether to stop preventative interventions and trachoma surveillance surveys (TSS) to determine whether the prevalence of active trachoma has rebounded after interventions have halted. In some contexts, programs also conduct trachomatous trichiasis (TT)-only surveys. A few costing studies of trachoma prevalence surveys exist, but none examine TIS, TSS, or TT-only surveys. Methodology/Principal findings: We assessed the incremental financial cost to the national program of TIS, TSS, and TT-only surveys, which are standardized cluster-sampled prevalence surveys. We conducted a retrospective review of expenditures and grant disbursements for TIS and TSS in 322 evaluation units in 11 countries between 2011 and 2018. We also assessed the costs of three pilot and five standard TT-only surveys in four countries between 2017 and 2018. The median cost of TIS and TSS was $8,298 per evaluation unit [interquartile range (IQR): $6,532–$10,111, 2017 USD]. Based on a linear regression with bootstrapped confidence intervals, after controlling for country, costs per survey did not change significantly over time but did decline by $83 per survey implemented in a single round (95% CI: -$108 –-$63). Of total costs, 80% went to survey fieldwork; of that, 58% went towards per diems and 38% towards travel. TT-only surveys cost a median of $9,707 (IQR: $8,537–$11,635); within a given country, they cost slightly more (106% [IQR: 94%–136%]) than TIS and TSS. Conclusions/Significance: The World Health Organization requires trachoma prevalence estimates for validating the elimination of trachoma as a public health problem. This study will help programs improve their planning as they assemble resources for that effort. Author summary: The global health community is working to eliminate trachoma, a bacterial disease that causes blindness. The elimination strategy includes offering antibiotics to everyone living in communities with a high prevalence of active trachoma, also known as mass drug administration, and providing surgeries for people with advanced trachoma. The World Health Organization requires that countries conduct surveys to see whether a district has reached the prevalence benchmarks for stopping population-level prevention interventions against trachoma. After stopping these interventions, programs conduct more surveys to make sure that trachoma has remained at bay. Trachoma programs must include the costs of these surveys in their budgets. Although some estimates of the costs of baseline trachoma prevalence surveys already exist, none examine the costs of additional surveys required later in the program. In this paper, we analyze the costs of over 300 of these surveys. We find that they cost about $8,000-$10,000 per survey, varying widely by country. Variations are mostly driven by how much it costs to pay surveyors and transport them to survey sites. Costs did not appear to change over time. With the data that we present in this paper, national programs will be more prepared to plan for monitoring the elimination of trachoma.