Costs and Consequences of Malaria Control in Sub-Saharan Africa: The Economics of Vector Control and Parasitological Diagnosis

Abstract

Economic evaluations of health intervention programs can provide decision makers with quantitative information on how to allocate the scare resources available for health investment. Malaria is the single most important parasitic infection in humans and accounts for a large proportion of the disease burden of sub-Saharan Africa. Currently many strategies are being employed for malaria prevention, and there is a need for evaluation of the various strategies being used. Additionally, routine malaria diagnosis in Africa often leads to mis-use of anti-malarial drugs and there is an urgent need to assess the cost implications of strategies for diagnostic improvement. Costs and cost-effectiveness of vector control Economic evaluations of ITNs (insecticide treated bednets) and IRS (indoor residual spraying) have been conducted in several settings but few of these evaluations relate to the scope and scale of interventions currently underway. Furthermore, few of these evaluations used comparable methodologies. We developed a standardized methodology for the economic evaluation of malaria vector control programs by reviewing and refining existing guidelines. Utilizing this methodology we collected new data from several settings (Eritrea, Malawi, Senegal, and Tanzania) and reanalyzed existing datasets from others (Togo, South Africa, and Mozambique). These sites were chosen to represent geographic variability as well as a diversity of implementation models for ITN delivery. The goals of this thesis were threefold: (1) to evaluate the relative cost and cost-effectiveness of ITNs and IRS for vector control in sub-Saharan Africa, (2) to evaluate the relative cost and cost-effectiveness of different implementation strategies for ITN delivery, and (3) to estimate the costs of introducing RDTs and their effect on the cost of case management of febrile patients. The ITN programs which we evaluated were chosen to represent five different delivery strategies: (1) free delivery through integrated vaccination campaigns (Togo), (2) free delivery through routine services and community mechanisms (Eritrea), (3) highly subsidized delivery through routine services (Malawi), (4) subsidized delivery through the commercial sector utilizing vouchers aimed at pregnant women and infants (Tanzania), and (5) pure commercial sector subsidization (Senegal). ITN/IRS Results The results of the studies generally showed that both interventions remained attractive uses of health resources in a low income country context under almost any scenario. More specifically, for conventional ITNs (targeted to children) the cost per treated net year of protection (TNY) and child death averted ranged from USD 1.21 to USD 6.05 and USD 438 to USD 2,199, respectively. Long-Lasting Insecticidal Net (LLIN) scenarios (also targeted to children) resulted generally in improved cost-effectiveness (USD 1.38 to USD 1.90 per TNY and USD 502 to USD 692 per death averted). IRS was more expensive in base scenarios, with a total cost per person year of protection of USD 3.27 in KwaZulu-Natal and USD 3.90 in Mozambique, this resulted in costs per death averted of USD 3,933 and USD 4,357. ITN programs appeared to be a more efficient strategy for the prevention of child mortality in highly endemic sub-Saharan African settings. However, this was dependant on both effective use of nets and a preferential usage of nets by children. Generally, the cost effectiveness of either strategy was heavily dependant on the cost of the commodities and their effective lifetime (nets for ITN programs and insecticide for IRS programs). ITN programs benefited clearly from a shift to LLINs. Under most scenarios free net delivery utilizing integrated campaigns appeared the most attractive method for short term “catch-up” in coverage levels for ITNs. The other strategies that were reviewed appeared to be better suited to the long term maintenance of coverage (“keep-up”). The data presented here provide a significant amount of new information collected and analyzed in a comparable manner to aid in decision making regarding vector control for malaria in sub-Saharan Africa. Costs of introducing rapid diagnostic tests in Tanzania We also conducted a study on the costs of implementation of Rapid Diagnostic Tests (RDTs) for malaria in Dar Es Salaam, Tanzania. Data were collected both at the level of individual patients and for entire health facilities. RDTs significantly lowered patient expenditure on drugs (by USD 0.37; p=0.001) and provider drug costs (by USD 0.44; p=0.014), but did not significantly reduce patients’ overall expenditures (USD 1.08 vs. USD 1.36) and have increased total provider costs (USD 3.62 vs. USD 2.31). Clinician’s compliance with tests was higher in clinics with RDTs than in those with routine microscopy. Use of the economic data in this thesis will hopefully help to provide a better evidence base for program managers to make more rational and efficient decisions about malaria control options and case management of febrile patients.