Accurate and reliable diagnostic tools are an essential requirement for neglected tropical diseases (NTDs) programmes. However, the NTD community has historically underinvested in the development and improvement of diagnostic tools, potentially undermining the successes achieved over the last 2 decades. Recognizing this, the WHO, in its newly released draft roadmap for NTD 2021–2030, has identified diagnostics as one of four priority areas requiring concerted action to reach the 2030 targets. As a result, WHO established a Diagnostics Technical Advisory Group (DTAG) to serve as the collaborative mechanism to drive progress in this area. Here, the purpose and role of the DTAG are described in the context of the challenges facing NTD programmes.

Global programs targeting 5 preventive chemotherapy neglected tropical diseases (PC-NTDs) have scaled up rapidly in recent decades due, in large part, to the generous drug donations from 6 pharmaceutical companies—Eisai; Johnson & Johnson (J&J); GlaxoSmithKline (GSK); Merck & Co., Inc., Kenilworth, New Jersey, United States of America (MSD); Merck KgaA; and Pfizer. Today, the scale of the PC-NTD drug donation programs is staggering. Nearly 15 billion tablets have been manufactured, packaged, shipped, and distributed in order to reach the people in need. The supply chains established to support such massive operations are enormously complex. Here, we describe a unique public–private partnership that was formed to bring together supply chain expertise to overcome the critical challenges associated with such large-scale production and delivery of donated pharmaceutical products.

As lymphatic filariasis (LF) programs move closer to established targets for validation elimination of LF as a public health problem, diagnostic tools capable of supporting the needs of the programs are critical for success. Known limitations of existing diagnostic tools make it challenging to have confidence that program endpoints have been achieved. In 2019, the World Health Organization (WHO) established a Diagnostic Technical Advisory Group (DTAG) for Neglected Tropical Diseases tasked with prioritizing diagnostic needs including defining use-cases and target product profiles (TPPs) for needed tools. Subsequently, disease-specific DTAG subgroups, including one focused on LF, were established to develop TPPs and use-case analyses to be used by product developers. Here, we describe the development of two priority TPPs for LF diagnostics needed for making decisions for stopping mass drug administration (MDA) of a triple drug regimen and surveillance. Utilizing the WHO core TPP development process as the framework, the LF subgroup convened to discuss and determine attributes required for each use case. TPPs considered the following parameters: product use, design, performance, product configuration and cost, and access and equity. Version 1.0 TPPs for two use cases were published by WHO on 12 March 2021 within the WHO Global Observatory on Health Research and Development. A common TPP characteristic that emerged in both use cases was the need to identify new biomarkers that would allow for greater precision in program delivery. As LF diagnostic tests are rarely used for individual clinical diagnosis, it became apparent that reliance on population-based surveys for decision making requires consideration of test performance in the context of such surveys. In low prevalence settings, the number of false positive test results may lead to unnecessary continuation or resumption of MDA, thus wasting valuable resources and time. Therefore, highly specific diagnostic tools are paramount when used to measure low thresholds. The TPP process brought to the forefront the importance of linking use case, program platform and diagnostic performance characteristics when defining required criteria for diagnostic tools.

Chronic intestinal schistosomiasis can cause severe hepatosplenic disease and is a neglected tropical disease of public health importance in sub-Saharan Africa, including Kenya. Although the goal of control programs is to reduce morbidity, milestones for program performance focus on reductions in prevalence and intensity of infection, rather than actual measures of morbidity. Using ultrasound to measure hepatosplenic disease severity is an accepted method of determining schistosomiasis-related morbidity; however, ultrasound has not historically been considered a fielddeployable tool because of equipment limitations and unavailability of expertise. A point-of-care tablet-based ultrasound system was used to perform abdominal ultrasounds in a field investigation of schistosomiasis-related morbidity in western Kenya; during the study, other pathologies and pregnancies were also identified via ultrasound, and participants referred to care. Recent technological advances may make it more feasible to implement ultrasound as part of a control program and can also offer important benefits to the community.

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