Development of new malaria diagnostics: matching performance and need

Abstract

Despite advances in diagnostic technology, significant gaps remain in access to malaria diagnosis. Accurate diagnosis and misdiagnosis leads to unnecessary waste of resources, poor disease management, and contributes to a cycle of poverty in low-resourced communities. Despite much effort and investment, few new technologies have reached the field in the last 30 years aside from lateral flow assays. This suggests that much diagnostic development effort has been misdirected, and/or that there are fundamental blocks to introduction of new technologies. Malaria diagnosis is a difficult market; resources are broadly donor-dependent, health systems in endemic countries are frequently weak, and the epidemiology of malaria and priorities of malaria programmes and donors are evolving. Success in diagnostic development will require a good understanding of programme gaps, and the sustainability of markets to address them. Targeting assay development to such clearly defined market requirements will improve the outcomes of product development funding. Six market segments are identified: (1) case management in low-resourced countries, (2) parasite screening for low density infections in elimination programmes, (3) surveillance for evidence of continued transmission, (4) clinical research and therapeutic efficacy monitoring, (5) cross-checking for microscopy quality control, and (6) returned traveller markets distinguished primarily by resource availability. While each of these markets is potentially compelling from a public health standpoint, size and scale are highly variable and continue to evolve. Consequently, return on investment in research and development may be limited, highlighting the need for potentially significant donor involvement or the introduction of novel business models to overcome prohibitive economics. Given the rather specific applications, a well-defined set of stakeholders will need to be on board for the successful introduction and scaling of any new technology to these markets.

Keywords: Malaria; Malaria diagnostics market; Rapid diagnostic testing; Target product profiles.

Fig. 1

The importance of six malaria diagnostic markets in different epidemiological settings. As parasite prevalence declines (left to right), estimation of transmission becomes more dependent on low limit of detection screening and survey assays. Slide cross-checking and research markets cut across endemic and non-endemic settings

Fig. 2

Stylized time course of an untreated Plasmodium falciparum infection in a host, and the impact of varying thresholds of detection on assay positivity. Red bars represent episodes of fever. Derived from observations of controlled infections to induce fever in tertiary syphilis patients, compiled by Collins and Jeffreys, US CDC. Unpublished data