Post-2015 Consensus: Health Perspective - Malaria, Raykar and Laxminarayan
Despite a 42% decrease in global malaria mortality since 2000, the disease was estimated to have caused 627,000 deaths worldwide in 2012. 90% of these deaths occurred in Sub-Saharan Africa and 77% were in children under five. In addition to the considerable mortality burden, malaria-endemic countries also bear considerable indirect long-term costs associated with physical and cognitive retardation, malnutrition, anaemia and increased disease susceptibility of its surviving population.
Considerable progress has been made; in the decade from 2000 there was a 26% decline in malaria-specific mortality rates globally while the estimated global incidence of malaria declined by 17%. However, there remains the threat of resistance developing to artemesinin, the drug of choice, and long-lasting insecticide-treated bed nets (LLITNs) have yet to be fully deployed. We therefore consider two targets:
A. Delay artemisinin resistance greater than 1% until 2025 through a combination of quality artemisinin combination therapies (ACTs), multiple first-line therapies (MFTs) and resistance containment efforts
B. Reduce malaria incidence by 50% between 2015 and 2025 through mass distribution of LLITNs
Artemisinin resistance is one of the greatest threats to global malaria control efforts today. Artemisinins have been responsible for averting millions of deaths from falciparum malaria and there are no other drugs available today or in the late stages of development that are nearly as effective. An increasing number of endemic countries have deployed highly effective ACTs. Use of MFTs, a strategy wherein multiple different first-line therapies are simultaneously made available through both public and private healthcare providers, represents an extension of treatment with a range of combinations to the population scale, to delay the emergence of resistance.
LLITNs have been proven to prevent malaria transmission. Their use by a majority of a target community provides protection even to those who do not sleep under LLITNs. They reduce the incidence of uncomplicated malaria by 50% compared to no use of nets at all and by 39% compared to the use of untreated nets, but need to be maintained and replaced at intervals.
Studies have been done on the cost-effectiveness of combinations of malaria control interventions in Western and Southern/Eastern sub-Saharan Africa, regions with high transmission rates but different disease burdens. In Western Africa, the region with a greater at-risk population, case management including treatment with ACTs at 80% target coverage is the most cost effective intervention ($9 per DALY averted). In Southern and Eastern Africa, for this intervention to be the most cost effective, the target coverage needed is 95% (costing $12 per DALY averted). In both regions, use of ITNs plus case management with ACTs is the next most cost-effective intervention.
We can use these estimates to calculate the cost effectiveness of these interventions for the combined sub-regions of sub-Saharan Africa, using DALY values of $1,000 and $5,000. For the delay of the development of artemisinin resistance until 2025, the BCRs are very large: 40 and 201 respectively for the low and high values of a DALY at 3% discount rate. Delaying resistance and reducing the incidence of malaria by 50% through ITNs is also highly cost-effective, with BCRs of 17 and 83 for the two cases at a discount rate of 3%. Because malaria contributes to child mortality and morbidity directly as well as indirectly through increased susceptibility to other infections, this analysis underestimates the DALYs averted.
There are, of course challenges. Malarial symptoms make it difficult to diagnose in the field, so expensive ACTs are used for non-malarial patients, who are also not treated appropriately for their actual illness. The development and rollout of rapid diagnostic testing should improve matters. ACTs are also relatively expensive, but successful pilot studies on the Affordable Medicines Facility malaria (AMFm) present a case in favor of making funds available for governments of developing countries to buy drugs and distribute them at lower prices. Finally, reducing malaria incidence requires substantial and costly scaling up of treatment coverage.