The Economic Value of Long-Lasting Insecticidal Nets and Indoor Residual Spraying Implementation in Mozambique

Abstract

AbstractMalaria-endemic countries have to decide how much of their limited resources for vector control to allocate toward implementing long-lasting insecticidal nets (LLINs) versus indoor residual spraying (IRS). To help the Mozambique Ministry of Health use an evidence-based approach to determine funding allocation toward various malaria control strategies, the Global Fund convened the Mozambique Modeling Working Group which then used JANUS, a software platform that includes integrated computational economic, operational, and clinical outcome models that can link with different transmission models (in this case, OpenMalaria) to determine the economic value of vector control strategies. Any increase in LLINs (from 80% baseline coverage) or IRS (from 80% baseline coverage) would be cost-effective (incremental cost-effectiveness ratios ≤ $114/disability-adjusted life year averted). However, LLIN coverage increases tend to be more cost-effective than similar IRS coverage increases, except where both pyrethroid resistance is high and LLIN usage is low. In high-transmission northern regions, increasing LLIN coverage would be more cost-effective than increasing IRS coverage. In medium-transmission central regions, changing from LLINs to IRS would be more costly and less effective. In low-transmission southern regions, LLINs were more costly and less effective than IRS, due to low LLIN usage. In regions where LLINs are more cost-effective than IRS, it is worth considering prioritizing LLIN coverage and use. However, IRS may have an important role in insecticide resistance management and epidemic control. Malaria intervention campaigns are not a one-size-fits-all solution, and tailored approaches are necessary to account for the heterogeneity of malaria epidemiology.

Figure 1.

JANUS Malaria clinical outcomes model structure.

Figure 2.

Malaria episodes per 1,000 persons over 3-year campaigns by region in Mozambique ([A] northern region; [B] central region; and [C] southern region) and assumed regional insecticide resistance patterns and long-lasting insecticidal net (LLIN) usage rates. Dotted lines indicate that the current malaria control strategies are maintained.

Figure 3.

Breakdown of total costs (intervention costs, direct health-care costs, and productivity losses) per 1,000 persons targeted for intervention by region in Mozambique ([A] northern region; [B] central region; and [C] southern region) and assumed regional insecticide resistance patterns and long-lasting insecticidal net (LLIN) usage rates.

Figure 4.

Impact of increasing long-lasting insecticidal net (LLIN) usage on the number of additional malaria episodes averted over 3 years for LLIN and indoor residual spraying (IRS) campaigns in the northern and southern regions of Mozambique. (A) Northern region with a baseline of 80% IRS coverage; (B) northern region with a baseline of 80% LLIN coverage; (C) southern region with a baseline of 80% IRS coverage; and (D) southern region with a baseline of 80% LLIN coverage.