Cost of the national malaria control program and cost-effectiveness of indoor residual spraying and insecticide-treated bed net interventions in two districts of Madagascar

Background: Madagascar had made significant progress in the fight against malaria. However, the number of malaria cases yearly increased since 2011. Methods: Using a societal perspective, this study aimed to estimate the cost of the National Malaria Control Program (NMCP) through the first national malaria strategic plan (implemented over the period 2009-2013) and to assess the cost-effectiveness of two individually implemented malaria control interventions (indoor residual spraying (IRS) and insecticide-treated nets (ITNs)) in two districts, Ankazobe and Brickaville. The cost-effectiveness ratio (CER) of ITN intervention was then compared to the CER of IRS intervention to identify the most cost-effective intervention, with the reference scenario that assumes the absence of vector control interventions, i.e. no consistent use of ITNs every night and no application of IRS at the primary residence within the last 12 months. The cost of the NMCP and the costs incurred in the implementation of each intervention at the district level were initially estimated. Using two outcomes, the CERs of ITN (IRS) was the total cost of ITN (IRS) divided by the number of persons protected or the number of disability-adjusted life years (DALYs) averted. A deterministic univariate sensitivity analysis was conducted to assess the robustness of the results with a discount rate of 2.5% (0-5%) (costs and DALYs) and a 95% CI (person protected). Results: From 2009 to 2013, the NMCP cost USD 45.4 million per year, equivalent to USD 2.0 per capita per year. IRS implementation costs were four times higher than those of ITNs. The CER of IRS per case protected was higher than the CER of ITNs, at USD 295.1 (r=0-5%, 285.1-306.1) compared to USD 48.6 (46.0-51.5) in Ankazobe and USD 26.5 (24.8-28.4) in Brickaville. The CERs per DALY averted were for IRS, USD 427.6 (413.0-546.3) in Ankazobe and USD 45.3 (42.2-48.4) in Brickaville and for ITNs, USD 85.4 (80.8-90.5) in Ankazobe. Compared to the country GDP per capita (USD PPP 1494.6 in 2013), ITN intervention was highly cost-effective while IRS intervention was only cost-effective. Conclusion: In the Malagasy context, IRS intervention cost more and was less effective than ITN intervention. Willingness to pay for IRS is questioned. A relevant budget impact analysis should be conducted before a potential extension of this intervention.