Global economic costs due to vivax malaria and the potential impact of its radical cure: A modelling study

Abstract

Background In 2017, an estimated 14 million cases of Plasmodium vivax malaria were reported from Asia, Central and South America, and the Horn of Africa. The clinical burden of vivax malaria is largely driven by its ability to form dormant liver stages (hypnozoites) that can reactivate to cause recurrent episodes of malaria. Elimination of both the blood and liver stages of the parasites (“radical cure”) is required to achieve a sustained clinical response and prevent ongoing transmission of the parasite. Novel treatment options and point-of-care diagnostics are now available to ensure that radical cure can be administered safely and effectively. We quantified the global economic cost of vivax malaria and estimated the potential cost benefit of a policy of radical cure after testing patients for glucose-6-phosphate dehydrogenase (G6PD) deficiency. Methods and findings Estimates of the healthcare provider and household costs due to vivax malaria were collated and combined with national case estimates for 44 endemic countries in 2017. These provider and household costs were compared with those that would be incurred under 2 scenarios for radical cure following G6PD screening: (1) complete adherence following daily supervised primaquine therapy and (2) unsupervised treatment with an assumed 40% effectiveness. A probabilistic sensitivity analysis generated credible intervals (CrIs) for the estimates. Globally, the annual cost of vivax malaria was US$359 million (95% CrI: US$222 to 563 million), attributable to 14.2 million cases of vivax malaria in 2017. From a societal perspective, adopting a policy of G6PD deficiency screening and supervision of primaquine to all eligible patients would prevent 6.1 million cases and reduce the global cost of vivax malaria to US$266 million (95% CrI: US$161 to 415 million), although healthcare provider costs would increase by US$39 million. If perfect adherence could be achieved with a single visit, then the global cost would fall further to US$225 million, equivalent to $135 million in cost savings from the baseline global costs. A policy of unsupervised primaquine reduced the cost to US$342 million (95% CrI: US$209 to 532 million) while preventing 2.1 million cases. Limitations of the study include partial availability of country-level cost data and parameter uncertainty for the proportion of patients prescribed primaquine, patient adherence to a full course of primaquine, and effectiveness of primaquine when unsupervised. Conclusions Our modelling study highlights a substantial global economic burden of vivax malaria that could be reduced through investment in safe and effective radical cure achieved by routine screening for G6PD deficiency and supervision of treatment. Novel, low-cost interventions for improving adherence to primaquine to ensure effective radical cure and widespread access to screening for G6PD deficiency will be critical to achieving the timely global elimination of P. vivax.

Resource allocation strategies for insecticide-treated bed nets to achieve malaria eradication

“…By using ITNs as the sole means to reduce mosquito-to-human transmission, we did not capture the complexities of other key interventions that play a role in burden reduction and elimination, the geospatial heterogeneity in cost-effectiveness and optimized distribution of intervention packages on a sub-national level, or related pricing dynamics (Conteh et al, 2021, Drake et al, 2017). For P. vivax in particular, reducing the global economic burden and achieving elimination will depend on incorporation of hypnozoitocidal treatment and G6PD screening into case management (Devine et al, 2021). Furthermore, for both parasites, intervention strategies generally become more focal as transmission decreases, with targeted surveillance and response strategies prioritized over widespread vector control.…”

“…[29,30] For P. vivax in particular, reducing the global economic burden and achieving elimination will depend on incorporation of hypnozoitocidal treatment and G6PD screening into case management. [31] Furthermore, for both parasites, intervention strategies generally become more focal as transmission decreases, with targeted surveillance and response strategies prioritized over widespread vector control. Therefore, policy decisions should additionally be based on analysis of country-specific contexts.…”

Using observed incidence to calibrate the transmission level of a mathematical model for Plasmodium vivax dynamics including case management and importation

“…Long considered as a benign malaria parasite, Plasmodium vivax is now increasingly recognized as an important public health issue, due to its potential severe clinical outcomes, its large health and socio-economic burden and the challenges associated with its elimination and control [1] , [2] , [3] . In 2017, [4] estimated about 14 million cases worldwide, and more than 3 billion people living within the limits of the parasite transmission across the globe.…”

Band 3–mediated Plasmodium vivax invasion is associated with transcriptional variation in PvTRAg genes

“…It is more difficult to eliminate than P. falciparum, in part because of its unique biologic properties, which include hypnozoites (dormant forms), gametocyte formation during the first blood-stage cycle, and reticulocyte tropism, which results in lower peripheral parasite densities and cryptic cycles in the spleen and bone marrow (Silva-Filho et al, 2020;Kho et al, 2021). Although P. vivax is increasingly recognized as a cause of morbidity and mortality (Price et al, 2009;Battle and Baird, 2021) and represents a substantial economic burden (Devine et al, 2021), major knowledge gaps remain, including the molecular mechanism underlying reticulocyte invasion. A better understanding of receptor-ligand interactions involved in this process could provide new targets for vaccine development (Beeson et al, 2016;Tham et al, 2017).…”