Humanitarian Evaluation of Spatial Emanators for Malaria Control

The overall aim of this study is to evaluate the feasibility, implementation, public health effectiveness, durability, acceptability and cost of delivering long-lasting spatial emanators at scale through United Nations High Commissioner for Refugees (UNHCR) humanitarian supply chains and distribution systems in northern South Sudan. Primary objective: To determine whether distribution of Guardian™ long-lasting spatial emanators reduces all-age malaria infection prevalence at 6 months in intervention populations compared with contemporaneous control populations during Phase 1 of the study. Secondary objectives: * Estimate the effect of Guardian™ on indoor and outdoor mosquito biting rate, including female Anopheles landing rates. * Evaluate the feasibility and fidelity of humanitarian delivery through UNHCR supply chains, including timeliness, household coverage, adequacy of units relative to shelter volume, unpacking, correct placement and retention. * Assess acceptability and safety, including user understanding, perceived benefit, barriers to use, product-related concerns and willingness to continue use or receive replacement units. * Assess product durability and performance through field observations of physical integrity and quantitative chemical analysis of retrieved units. * Describe changes in routine health facility malaria indicators and household-reported febrile illness as complementary measures of public health impact. Tertiary and exploratory objectives: * Estimate the cost and cost-efficiency of humanitarian delivery, including cost per unit delivered, household reached, person protected and correctly protected person-month, and estimate cost-effectiveness where supported by effectiveness data. * Examine whether coverage, dose adequacy, correct placement, retention, shelter characteristics, population movement, seasonality and other contextual factors explain heterogeneity in epidemiological or entomological effects. * Compare implementation performance and acceptability across different beneficiary groups (refugee camps, host communities and newly arriving displaced populations). * Integrate epidemiological, entomological, implementation, qualitative, durability and economic findings to inform transition of long-lasting spatial emanators toward routine use as a humanitarian vector control commodity and guide future UNHCR, Ministry of Health and WHO implementation and scale-up decisions.

Inclusion Criteria: * Residents of the selected study populations in Yida, Ajuong Thok and Pamir, newly arrived refugee populations included in either phase, and dispersed host communities included during Phase 2. * For malaria prevalence surveys: usual residents of sampled households who are randomly selected for testing, irrespective of age, sex, malaria symptoms or previous Guardian™ exposure. * Adults aged 18 years or older who provide informed consent. For children, a parent or legal guardian must provide consent, with age-appropriate assent for children aged 7-17 years. * For household implementation monitoring: households eligible for Guardian™ distribution within the selected intervention populations, with an adult representative available to provide informed consent. * For household entomological monitoring: selected sentinel households whose adult representative provides consent for collection activities. * For human landing catches: trained adult household occupants who provide separate written informed consent and agree to the collector safety procedures, including malaria chemoprophylaxis and regular malaria testing. Exclusion Criteria: * Individuals or households outside the sampling frame for the relevant evaluation component. * Individuals who decline participation, or children for whom parent or guardian consent or required assent is not obtained. * For household monitoring: households without an adult representative available to provide informed consent. * Households that cannot be accessed safely. * Individuals or households for whom participation would create an unacceptable safety, protection or confidentiality risk. Participation in research evaluation activities is voluntary and does not affect access to Guardian™, health care or any other humanitarian assistance.