Strategies and approaches to vector control effectiveness toward the elimination of malaria in mainland Tanzania: An implementation case study analysis.

Effective malaria control and elimination require continuous monitoring of vector control interventions, entomological indicators, and their relationship with malaria case incidence. This implementation case study describes data fragmentation and develops a unified, granular profile of malaria burden and vector control at the district level in mainland Tanzania. By integrating data on malaria burden, vector control interventions, and intervention coverage, the study complements existing stratification approaches and generates actionable insights to inform policy and strategic decision-making on effective interventions at the council level. We extracted monthly council-level malaria incidence data (2018-2022) from DHIS2. Insecticide-treated net (ITN) access was estimated using ITN distribution and population data through a stock-and-flow model, assuming a Tanzania-specific median net lifespan of 2.15 years. Data on indoor residual spraying (IRS) implementation and entomological monitoring reports (2011-2022) were reviewed. Rainfall data were summarized and visualized as overlapping monthly time series. According to the annual vector control report (AVCR) for 2021 and 2022, the mean modeled council-level population access to ITNs was 63.9% in 2021 and 65.2% in 2022. Across 184 councils, 17.4% had low ITN access (<50%), 59.2% had moderate access (51-80%), and 23.4% achieved sufficient access (>80%). Councils with ITN access above 80% consistently reported lower malaria incidence rates, whereas those with access below 50% were generally associated with higher malaria burden. Higher ITN access was associated with lower malaria incidence, underscoring the importance of accurate quantification and timely distribution of insecticide-treated nets. In areas where Anopheles arabiensis predominates, complementary outdoor vector control interventions may be needed to address residual outdoor transmission. District-level vector control profiling can enhance the effectiveness of malaria programmes by supporting evidence-based resource allocation and adaptive intervention strategies.