Impact of long-lasting insecticidal nets (LLINs) treated with pyrethroid plus pyriproxyfen vs LLINs treated with pyrethroid plus piperonyl butoxide on malaria incidence in Uganda: a cluster-randomised trial

Intervention:                                                                    

A universal LLIN distribution campaign will be led by the National Malaria Control Division and partners. LLINs will be distributed to the sub-county surrounding each cluster. A cluster will be defined as a level III/IV health center (malaria reference center (MRC) and adjacent villages whose population seek care at the center defined as the target area.                                                        

Evaluation Methodology:                                            

1) Health facility surveillance. For all patients presenting to the Malaria Reference Centers (MRCs), information on the location of their residence will be collected. Estimates of malaria incidence will be calculated by dividing the number of laboratory-confirmed malaria cases diagnosed at each MRC (among patients residing in the catchment area per unit time) by the total population of the MRC target area. To evaluate the impact of the intervention, we will estimate malaria incidence at the MRCs for the 24 months after LLIN distribution.
2) Enumeration and census surveys. To estimate the population of the MRC target areas, and to generate a sampling frame for the first community survey (to be carried out 12 months after LLIN distribution), we will enumerate and map all households within each MRC target area. To derive a more accurate estimate of the population of the MRC target areas, we will conduct a census survey of the MRC target areas, concurrently with the first cross-sectional survey.
3) Cross-sectional community surveys. At baseline, and at 12 and 24 months following LLIN distribution, randomly selected households will be surveyed from each of the 64 clusters. The survey will include a household questionnaire and clinical & laboratory evaluation of children aged 2-10 years. We will survey at least 50 households in each cluster (n=3,200), aiming to recruit all eligible children in each household (approximately 5,760) per survey. In 32 clusters (one per district), we will enroll residents of all ages from participating households into the clinical survey, to estimate the impact of COVID-19 on malaria.  
4) Entomology surveys (not done due to funding limitations)
5) Economic evaluation. Cost-effectiveness will be assessed at the end of the study by collecting cost data for materials and labour and using effectiveness data to estimate the number of malaria cases averted. Incremental cost-effectiveness ratios (USD per disability-adjusted life year averted and per malaria case averted) will be the primary outcomes.
6) LLIN survivorship and durability (not done due to funding limitations).                                                                  

Vector Control

Jan 2022 — Dec 2024

Uganda