LLIN Study
LLIN Study title: Durability monitoring of long-lasting insecticidal nets (LLINs) in Uganda distributed during the 2020 mass campaign.

Study period: ongoing (2020-2023)

Use of long-lasting insecticidal nets (LLINs) is the primary strategy for prevention of malaria in Uganda. Uganda distributes LLINs every 3 years to achieve universal coverage of the population (1net for every two persons). The Ministry of Health needs information on the durability of different LLIN products in local settings to provide country-level data to guide national program planning for long term coverage with LLINs. PACE is conducting a 3-year study to monitor the durability of the 5 different LLIN brands distributed during the 2020 mass national campaign to fill this gap. The study districts were purposively selected from the region in collaboration with NMCD to ensure that all net brands distributed in the 2020 UCC are represented.

The primary objective of the study is:

To assess the physical durability of 5 different brands of nets over a three-year period, estimate median LLIN survival and identify major determinants of field performance.
The secondary objectives are:

To describe major behavioural aspects of net care and repair and their impact on physical durability
To assess the insecticidal effectiveness (bio-efficacy) and chemical residue of 5 ITN brands during three years of field use

The study is a prospective follow up of a cohort of nets distributed through the 2020 mass campaign. Within the first 6 months following the mass campaign, a representative sample of campaign nets from the study location will be identified through a cluster household survey with all campaign nets from consenting households forming the study cohort. These nets will then be labelled with a unique identifier and their presence and physical condition assessed at this baseline and in three additional annual surveys together with household characteristics and use, care and repair behavior for the net. At each assessment (baseline, 12, 24 and 36 months), sub-samples of campaign nets will be selected for insecticide effectiveness testing (bio-assays and chemical analysis). A baseline chemical residue assessment is expected to come from the routine post-procurement quality control.

The study will be conducted in 3 districts in the Bunyoro region. The districts shall receive 5 brands of nets (Interceptor, PermaNet 2.0 & 3.0, Royal Guard and Safenet) in the 20202 mass LLIN distribution campaign. Five sub counties, one with each of the five net brands, will be purposively selected for participation in the study. A 2 stage-sampling strategy will be used to select households for participation. Within each selected sub-county (cluster), 16 villages will be randomly selected from the existing UBOS census list for participation (UBOS, 2014). Villages will be mapped to form a sampling list of eligible households for enrolment. About 10 households will be randomly selected from each sampled village and nets in the households followed up over three years. A standard questionnaire will be used to collect household and net data. Physical durability of LLINs will be assessed by counting the number of holes on the nets. The integrity of nets will be quantified based on the proportion of LLINs with any hole and the proportionate hole index (pHI) for each net. A subsample of nets (30 LLINs per brand per site) will be withdrawn during baseline and each follow-up assessment to assess for insecticidal activity (bio efficacy and chemical analysis). Replacement nest will be given to these households.

COVID-19 Prevention during study activities

PACE is aware of the COVID-19 pandemic and its effects on health care as well as the provision of other services. A detailed COVID risk mitigation plan has been developed in line with Ministry of Health and Uganda National Council of Science and Technology (UNCST) guidelines to mitigate risk of COVID spread to staff and participants during the net durability monitoring study activities. All study staff and other partners engaged in this study, including vector control officers, Local Council leaders and VHTs will follow the risk mitigation plan throughout the period of study activities.

Study sites

Kikuuke, Kakumiro and Hoima districts in Bunyoro region, western Uganda

Study duration: 36 months

LLIN Durability Monitoring Study Progress (August, 2022)

Completed the Baseline Bioassay tests, and analysis and results disseminated
Compiled and disseminated a comprehensive Baseline Survey report that includes three study components (Physical integrity, Bioassay and chemical residue results)
Concluded 12 months survey data collection, analysis and presentation. 12 months Bioassay and Chemical Residual test are ongoing.
Commenced the two phased 24-month data collection on August, 2022. The next phase of 24 months data collection starts in November 2022.


Principal Investigators

Phellister Nakamya (PACE), Stephen Poyer (PSI), Jimmy Opigo (MOH), Henry Katamba (MOH)


Rebecca Babirye, Alex Ndyabakira, Catherine Maiteki-Sebuguzi, Damian Rutazaana, Mathias Mulyazaawo Kasule, Samuel Gonahasa


Global fund to fight AIDS, Tuberculosis and Malaria (through the Uganda Ministry of Health)


Program for Accessible health Communication and Education

Population services international

National Malaria Control Division, Ministry of Health