Estimating population ITN access at council level in Tanzania

Area of Science:

• Public Health
• Epidemiology
• Mathematical Modeling

Background:

• Malaria control in Tanzania relies on mass insecticide-treated net (ITN) distribution campaigns and routine access programs.
• Annual monitoring of ITN access is crucial for triggering mass campaigns and informing net procurement.
• Sub-national (council-level) ITN access data is needed for effective programmatic decision-making.

Purpose of the Study:

• To develop and validate a model for predicting annual ITN access at the council level in Tanzania.
• To assess the feasibility of using modeled ITN access data to inform malaria control strategies.

Main Methods:

• An age-structured stock and flow model was employed using council-level ITN distribution data (2012-2020).
• The model incorporated a Tanzania-specific ITN median lifespan of 2.15 years.
• Predicted ITN access was calculated based on nets-per-capita (NPC) and compared with regional survey data.

Main Results:

• The model accurately predicted council-level ITN access, aligning with regional survey data in 79% of regions with uniform ITN strategies.
• Divergences were observed in regions with varied ITN strategies across councils.
• ITN access exceeded 60% when nets issued as a percentage of the council population (NPP) surpassed 15%, and approached 80% at or above 20% NPP.

Conclusions:

• Modeling ITN access using country-specific decay rates, population data, and distribution records is a viable method for sub-regional monitoring.
• This approach provides valuable insights into ITN coverage between large-scale household surveys.
• The methodology offers a promising tool for malaria control programs in Tanzania and other endemic regions.