Assessing national vector control micro-planning in Zambia using the 2021 malaria indicator survey

Area of Science:

• Public Health
• Vector-Borne Disease Control
• Epidemiology

Background:

• Zambia implemented sub-district malaria control micro-planning in 2020, assigning specific areas to either long-lasting insecticidal nets (LLINs) or indoor-residual spraying (IRS).
• The 2021 Malaria Indicator Survey (MIS) data was used to evaluate the adherence to and effectiveness of this micro-planning strategy.

Purpose of the Study:

• To assess the implementation fidelity of the LLIN and IRS micro-planning strategy.
• To identify factors influencing household receipt of planned malaria interventions.
• To compare overall malaria vector control coverage in 2021 with pre-micro-planning levels from 2018.

Main Methods:

• Geographic Information System (GIS) analysis overlaying 3,550 household GPS points onto micro-planning maps.
• Mixed-effects regression models to determine factors affecting intervention receipt.
• Comparison of coverage indicators between the 2018 and 2021 MIS datasets.

Main Results:

• Overall, 60% of households received their assigned intervention, with higher success in LLIN areas (75.7%) compared to IRS areas (49.4%).
• Households in IRS-assigned areas had significantly lower odds of receiving planned (OR: 0.34) and any intervention (OR: 0.51) compared to LLIN areas.
• National LLIN coverage decreased by 27% in 2021 from 2018 levels, while IRS coverage remained similar; households receiving neither intervention increased by 13%.

Conclusions:

• The micro-planning strategy was more effective for LLIN distribution than IRS distribution.
• Despite the micro-planning efforts, overall vector control coverage declined in 2021 compared to 2018, indicating a need for strategy refinement.