Humanitarian Evaluation of Spatial Emanators for Malaria Control

NCT07886281 | Not Yet Recruiting Phase 4 DMC

• 2 other identifiers: UNLV-2026-310INV-108340
• Study Type: interventional
• Target: 32,584
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Malaria Infection

Keywords

Malaria; Vector control; Conflict displaced people; Temporary shelter; Spatial emanators

Outcome Measures

Primary Outcomes (1)

• All-age malaria infection prevalence at 6 months following Phase 1 Guardian™ deployment

  Percentage of randomly selected participants of all ages with a positive malaria rapid diagnostic test, irrespective of symptoms, calculated as the number with positive results divided by the number with valid results, multiplied by 100. Two separate Phase 1 comparisons will be conducted: Yida intervention versus Yida control, and Ajuong Thok intervention versus Pamir control. The effect measure will be the intervention-to-control prevalence ratio, adjusted for baseline malaria prevalence in the corresponding geographic sampling cluster and prespecified participant and household covariates.

  6 months after Phase 1 Guardian™ deployment.

Secondary Outcomes (2)

• Indoor female Anopheles landing rate

  Baseline and monthly during months 1-6 after distribution in each phase; baseline and monthly during months 1-3 for newly arriving refugees.

• Outdoor female Anopheles mosquito landing rate

  Baseline and monthly during months 1-6 after distribution in each phase; baseline and monthly during months 1-3 for newly arriving refugees.

Other Outcomes (14)

• Percentage of targeted households receiving Guardian™ within the planned distribution window

  At completion of each distribution round, up to 2 weeks after the start of distribution, in Phases 1 and 2

• Percentage of targeted households receiving at least one Guardian™ unit

  Phase 1: 1-2 weeks and 1, 3, 6, 9 and 12 months after distribution. Phase 2: 1-2 weeks and 1, 3 and 6 months. New arrivals: 1-2 weeks and 1 and 3 months in each phase.

• Percentage of recipient households receiving an adequate number of Guardian™ units for shelter volume

  Phase 1: 1-2 weeks and 1, 3, 6, 9 and 12 months after distribution. Phase 2: 1-2 weeks and 1, 3 and 6 months. New arrivals: 1-2 weeks and 1 and 3 months in each phase.

Study Arms (2)

Control

NO INTERVENTION

Guardian™ long-lasting spatial emanators

EXPERIMENTAL

Device: Guardian™ long-lasting spatial emanators

Interventions

Guardian™ long-lasting spatial emanators DEVICE

Arm Description: Guardian™ (SC Johnson \& Son, Racine, WI, USA) is a long-lasting spatial emanator. The active ingredient is transfluthrin (C15H12Cl2F4O2, 2.5 g/Guardian™, EPA Reg. number 432-1588). Each unit has a mean emanation rate of 4.7 mg/day, with 2 units installed per regular size room (12 m2/30 m3; 9.4 mg/day emanation per room). This intervention is designed to remain efficacious for 12-months upon opening.

Also known as: Spatial repellents

Guardian™ long-lasting spatial emanators

Eligibility Criteria

• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• The Mentor Initiative: lead
• United Nations High Commissioner for Refugees: collaborator
• University of Nevada, Las Vegas: collaborator

Study Sites (1)

The MENTOR Initiative, Jamjang

Jamjang, Pariang County, South Sudan

Location

Related Publications (7)

• Chen I, Miller SL, Msellemu D, Lugenge AG, Swai JK, Achee N, Andres M, Bibbs CS, Chareonviriyaphap T, Charlwood JD, Devine G, Elman N, Fillinger U, Flores-Mendoza C, Gibson S, Govella N, Gowelo S, Horstmann S, Kawada H, Kline D, Lloyd A, Lobo NF, Maia MF, Mmbando A, Moreno-Gomez M, Morrison AC, Mponzi W, Mwanga EP, Njoroge M, Ogoma SB, Okumu FO, Opiyo M, Oumbouke WA, Paliga J, Pongsiri A, Ponlawat A, Saeaung M, Salazar F, Sangoro O, Stevenson JC, Sukkanon C, Syafruddin D, Tambwe MM, Tangena JA, Vajda EA, Vazquez-Prokopec G, Wagman JM, Yan C, Allen IE, Moore SJ. Volatile pyrethroid spatial repellents for preventing mosquito bites: a systematic review and meta-analysis. EBioMedicine. 2025 Sep;119:105891. doi: 10.1016/j.ebiom.2025.105891. Epub 2025 Aug 26.

  PMID: 40866281 BACKGROUND

• Morrison AC, Reiner RC Jr, Elson WH, Astete H, Guevara C, Del Aguila C, Bazan I, Siles C, Barrera P, Kawiecki AB, Barker CM, Vasquez GM, Escobedo-Vargas K, Flores-Mendoza C, Huaman AA, Leguia M, Silva ME, Jenkins SA, Campbell WR, Abente EJ, Hontz RD, Paz-Soldan VA, Grieco JP, Lobo NF, Scott TW, Achee NL. Efficacy of a spatial repellent for control of Aedes-borne virus transmission: A cluster-randomized trial in Iquitos, Peru. Proc Natl Acad Sci U S A. 2022 Jun 28;119(26):e2118283119. doi: 10.1073/pnas.2118283119. Epub 2022 Jun 23.

  PMID: 35737833 BACKGROUND

• Syafruddin D, Asih PBS, Rozi IE, Permana DH, Nur Hidayati AP, Syahrani L, Zubaidah S, Sidik D, Bangs MJ, Bogh C, Liu F, Eugenio EC, Hendrickson J, Burton T, Baird JK, Collins F, Grieco JP, Lobo NF, Achee NL. Efficacy of a Spatial Repellent for Control of Malaria in Indonesia: A Cluster-Randomized Controlled Trial. Am J Trop Med Hyg. 2020 Jul;103(1):344-358. doi: 10.4269/ajtmh.19-0554. Epub 2020 May 14.

  PMID: 32431275 BACKGROUND

• Ochomo EO, Gimnig JE, Awori Q, Abong'o B, Oria P, Ashitiba NK, Polo B, Moshi V, Otanga H, Adung'o F, Ouma EA, Outa S, Ramaita E, Levine R, Odongo W, Harvey SA, Monroe A, Hudson A, Sandberg B, Hendrickson J, Zhao X, Zhou R, Liu F, Achee NL, Grieco JP. Effect of a spatial repellent on malaria incidence in an area of western Kenya characterised by high malaria transmission, insecticide resistance, and universal coverage of insecticide treated nets (part of the AEGIS Consortium): a cluster-randomised, controlled trial. Lancet. 2025 Jan 11;405(10473):147-156. doi: 10.1016/S0140-6736(24)02253-0. Epub 2024 Dec 19.

  PMID: 39709979 BACKGROUND

• Allan R, Scherrer R, Kasap OE, Paris L, Scott T, Sauskojus H, Wetherill O, Estecha-Querol S, Alkhalaf Z, Karakus M, Yilmaz A, Alten B, Messenger LA. Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria. BMC Med. 2025 Jul 3;23(1):401. doi: 10.1186/s12916-025-04244-2.

  PMID: 40611204 BACKGROUND

• Allan RJ, Scherrer R, Estecha-Querol S, Weetman D, Paris L, Ba'abba Goni U, Idris Abdulhamid F, Nfornuh Alenwi B, Ahmad S, Cross CL, Ashir GM, Waziri M, Ntadom G, Messenger LA. The effectiveness of long-lasting spatial repellent emanators against malaria in humanitarian crisis settings in northern Nigeria: a two-arm pragmatic, open-label, controlled trial. Lancet Infect Dis. 2026 May;26(5):464-474. doi: 10.1016/S1473-3099(25)00684-X. Epub 2026 Jan 8.

  PMID: 41520670 BACKGROUND

• Messenger LA, Furnival-Adams J, Chan K, Pelloquin B, Paris L, Rowland M. Vector control for malaria prevention during humanitarian emergencies: a systematic review and meta-analysis. Lancet Glob Health. 2023 Apr;11(4):e534-e545. doi: 10.1016/S2214-109X(23)00044-X.

  PMID: 36925174 BACKGROUND

MeSH Terms

Conditions

Malaria

Condition Hierarchy (Ancestors)

Protozoan Infections; Parasitic Diseases; Infections; Mosquito-Borne Diseases; Vector Borne Diseases

Study Officials

• Richard J Allan, PhD, OBE

  The Mentor Initiative

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Richard J Allan, PhD, OBE

CONTACT

+44 796193670; richard.allan@mentor-initiative.org

Louisa A Messenger, PhD

CONTACT

+1 702-449-3295; louisa.messenger@unlv.edu

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 9, 2026
• First Posted: October 21, 2026
• Study Start (Estimated): October 26, 2026
• Primary Completion (Estimated): November 30, 2027
• Study Completion (Estimated): November 30, 2028
• Last Updated: October 21, 2026

Record last verified: 2026-10

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: IPD will be available upon publication of the main trial manuscript, following trial completion and will be available indefinitely.
• Access Criteria: Summary findings from trial IPD will be published in open-access, peer reviewed papers and their supporting information. Following trial completion, IPD will be available indefinitely, upon publication of the main trial manuscript. All other relevant de-identified IPD are available from the trial Principal Investigators upon reasonable request.

Locations

SO (1)