Using modeled P. vivax prevalence data to estimate the market size for glucose-6-phosphate dehydrogenase (G6PD) deficiency tests in order to support decision making on service delivery models

Background: Plasmodium vivax (P. vivax) is estimated to be responsible for over 100 million clinical infections annually. The 8-aminoquinoline family of drugs, such as primaquine, can completely clear P.vivax parasites by killing malaria gametocytes and consequently blocking vector-borne transmission. However, the 8-aminoquinoline family of drugs can cause severe hemolysis in patients with reduced activity of the G6PD enzyme; therefore, the World Health Organization recommends identifying the G6PD status of patients infected with P. vivax malaria prior to administering these drugs. Point-of-care (POC) tests that can rapidly and affordably identify G6PD status are needed to support safer and wider use of the 8-aminoquinoline family of drugs. During the time that PATH has been supporting the development and market entry of POC G6PD quantitative and qualitative tests, we have also developed a computer program called GeoDX to estimate the P. vivax burden per health facility (i.e., the number of patients testing positive for P. vivax that visit each health facility), the total quantify of G6PD tests per country, and the associated costs. Materials and Methods: Leveraging data modeled by the Malaria Atlas Project—i.e., P. vivax prevalence and population per geographical area, geospatial facility data, and certain assumptions about facility catchment area—GeoDX estimates the P. vivax burden per health facility. This estimate was further used to calculate the total quantity of G6PD tests required per country and the associated costs over a ten-year period. GeoDX is interactive, and users can adjust parameters such as diagnosis-to-treatment algorithms, malaria elimination scenarios, and characteristics of any G6PD test for which they choose to generate country-specific data. Results and Conclusions: National malaria control programs and other program implementers can use the outputs of GeoDX to evaluate which use-case scenario would most likely attain the desired target coverage in the most effective manner. They can also use the outputs to determine what the cost impact of the selected G6PD diagnostic test(s) would be on their budget. Test manufacturers can use this same information to identify the production quantity required, which will enable them to evaluate their production costs and pricing structure over time.