Gloria Salome Shirima, Silas Steven Mirau, Charles D Mwalimu, Mponeja Gitanya, Nakul Chitnis, Samson Kiware, Thiery Masserey
Malaria persists across sub-Saharan Africa, partly due to insecticide resistance in malaria vectors and the short durability of insecticide-treated nets (ITNs). Next-generation insecticide-treated nets with dual active ingredients (such as chlorfenapyr and alpha-cypermethrin) have been developed to counteract these challenges, but their effectiveness and economic impact compared to current (pyrethroid (PY) and pyrethroid-piperonyl butoxide (PBO)) nets in varied transmission settings remain under evaluation. To inform the Tanzanian National Malaria Control Programme, we used an individual-based model of malaria transmission to assess the epidemiological and economic impacts of three ITN types (chlorfenapyr-α-cypermethrin, PBO, and standard pyrethroid nets). ITN effects were parameterized based on entomological experimental hut trial data in Tanzania. We simulated the deployment of each ITN type at various access levels through three delivery channels (targeted mass campaigns, school net programme, and reproductive and child health) across moderate and high transmission strata representative of Tanzania. We estimated reductions in clinical cases, total costs, and costs per case averted across net types. In both strata, chlorfenapyr-α-cypermethrin nets averted more malaria episodes per person per year for one-round mass distribution compared to PBO and PY nets. The impact remained high through the third-year post-distribution, indicating sustained long-term impact. Despite higher unit costs, chlorfenapyr-α-cypermethrin nets demonstrated a competitive cost per case averted compared to PBO and standard PY nets. These findings provide epidemiological and economic evidence to support Tanzania's National Malaria Control Programme in optimizing deployments of next-generation nets across delivery channels and transmission strata.