Evaluation of the Protective Efficacy of a Spatial Repellent to Reduce Malaria Prevalence in Uganda (Mossie-GO)

Evaluation of the Protective Efficacy of a Spatial Repellent to Reduce Malaria Prevalence in Children ≤ 5 Years of Age in Uganda: Study Protocol for a Cluster-randomized Double-blinded Control Trial: The Mossie-GO Trial

A cluster-randomized double-blinded control trial will be conducted in Uganda to demonstrate and quantify the protective efficacy (PE) of Mossie-GO, an active spatial repellent system disseminating transfluthrin, in reducing the prevalence of malaria in children ≤ 5 years of age, as determined by RDT positivity and confirmed by microscopy. The study's secondary objective is to measure the diversionary impact of the intervention on locally unprotected individuals and impact of the intervention on entomological correlates of transmission including vector densities, host seeking behaviour and insecticide resistance. This will be conducted using Centre of Disease Control (CDC) light traps in households, human landing catches and World Health Organisation (WHO) tube tests. Further data collection include household behavioural surveys, air sampling to quantify concentration of transfluthrin present in air, acceptability surveys and intervention safety monitoring.

Recruited households will be monitored across baseline data collection and followed up for 2 disease transmission seasons, for up to 18 months. The devices will be distributed to all consented eligible households in the two study arms: intervention and control. Intervention arm devices will be provided with transfluthrin treated discs and refill transfluthrin discs at frequent enough intervals to provide sustained protection. Households in the control arm will receive blank discs with no active ingredient. Households will be asked to continue using other malaria prevention practices, such as the use of bed nets, as recommended by national policy.

Study Overview

• Status: Not yet recruiting
• Conditions: Malaria; Mosquito-Borne Disease
• Intervention / Treatment: Device: Mossie-Go containing treated transfluthrin disc; Device: Mossie-Go containing untreated blank disc

Detailed Description

The impact of Mossie-GO on malaria cases will be determined through a blinded cluster randomized trial in malaria endemic settings. The device will be distributed to all consented eligible households in the two study arms: intervention and control. Intervention arm devices will be provided with transfluthrin treated discs and refill transfluthrin discs at frequent enough intervals to provide sustained protection. Households in the control arm will receive blank discs with no active ingredient and refill blank discs to maintain study blinding.

The Mossie-GO repellent device is approximately 8 cm3 and can be fitted with repellent discs impregnated with transfluthrin and a carrier oil. These discs sit above a fan that is powered by a small motor charged by solar energy. The device is expected to both prevent bites and cause some mortality to mosquitoes when switched on for 8-12 hours overnight for up to 1 calendar month. The discs then need to be replaced. One Mossie-GO device will be provided per household, along with a solar cell unit that will be connected to the Mossie-GO unit and must be placed in direct sunlight to charge the Mossie-Go unit during the day, for use in the evening. Households will be asked to continue using other malaria prevention practices, such as bed nets, as recommended by national policy.

At baseline, Mossie-GO will be distributed at the household level and should be placed in the room of the participant enrolled into the study (child ≤ 5 years of age) while they are sleeping. At the same time a baseline survey will be conducted and children ≤ 5 years of age will be tested for malaria using RDTs and microscopy, to determine baseline malaria prevalence. At this time, household surveys will also be conducted to classify housing structure and collect other variables which may impact the efficacy of the intervention. Following this period, sample size estimates may be adjusted based on malaria prevalence. All recruited households will be monitored at 6-monthly intervals and malaria testing will be done among children ≤ 5 years of age with RDTs and microscopy over a period of up to 18 months. Indoor light traps will be installed in selected households for approximately 3-4 nights in the 6 month intervals and run from 6pm to 7 am to collect mosquitoes indoors, and human landing catches will be conducted. Air sampling will also be conducted alongside mosquito collections to quantify the concentrations of transfluthrin in the air and to help inform entomological and epidemiological outcomes. An acceptability survey will also be conducted at the final data collection time point

The unit of randomization is a cluster, which is defined as a discrete village or area containing a minimum of 100 households. Clusters will be divided into core and buffer zones. Twenty eight clusters will be identified per study arm (treatment and control), thus fifty six clusters will be selected in total. Households within the core zone of clusters will receive the Mossie-GO device (intervention or control). Households within the buffer zones will not receive the Mossie-GO. While all households within the core zone of the cluster are receiving the device, they will not all be sampled for the evaluation of the primary objective (PE). Only a total of 100 eligible, consenting households will be sampled within the core zones. Household surveys will also be conducted in these 100 households. For the evaluation of the secondary outcomes, a subset of houses will be selected. Diversionary impact: 100 households in buffer zone; entomological sampling: 10% of households in core zone; air sampling 1 household every 500m in core zone.

The primary outcome (PE) will be compared between arms using logistic regression with a random effect for study cluster and adverse event data will be collected and summarised.

• Study Type: Interventional
• Enrollment (Estimated): 5600
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Robert Jones, PhD; Phone Number: +447745845880; Email: robert.jones@arctechinnovation.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Cluster level:

Number of households > 100

Household level:

Presence of a child ≤ 5 years of age at point of enrolment in the study

Adult head of household agrees to receiving and using the device as per manual instructions

Adult head of household agrees to data collection visits and household surveys

Children within household sleeps in cluster > 90% of nights during any given month

Individual level:

≤ 5 years of age when enrolled into the study

No plans for extended travel (> 1 month) outside of home during study

Not participating in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure during the trial

Provision of informed consent form (ICF) by the parent(s) or guardian

Participants not on regular malaria prophylaxis

Exclusion Criteria:

Cluster level:

Number of households < 100

Household level:

Presence of a child > 5 years of age at point of enrolment in the study

Adult head of household does not agree to data collection visits and household surveys

Children within household sleeps in cluster < 90% of nights during any given month

Households where study personnel identify a security risk (i.e., site where drugs are sold, residents are always drunk or hostile).

Individual level:

>5 years of age when enrolled into the study

Plans for extended travel (> 1 month) outside of home during study

Participating or planned participation in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure during the trial

No provision of ICF signed by the parent(s) or guardian

Participants on regular malaria prophylaxis

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention; All recruited households within the intervention arm will receive the Mossie-Go device containing transfluthrin treated discs and will be provided with refill transfluthrin discs at monthly intervals to provide sustained protection.	Device: Mossie-Go containing treated transfluthrin disc; The Mossie-GO repellent device is approximately 8 cm3 and can be fitted with repellent discs impregnated with transfluthrin and a carrier oil. These discs sit above a fan that is powered by a small motor charged by solar energy. The device is expected to both prevent bites and cause some mortality to mosquitoes when switched on for 8-12 hours overnight for up to 1 calendar month. The discs then need to be replaced.
Placebo Comparator: Control; All recruited households within the control arm will receive the Mossie-Go device containing untreated blank discs and will be provided with refill untreated blank discs at monthly intervals.	Device: Mossie-Go containing untreated blank disc; The Mossie-GO repellent device is approximately 8 cm3 and can be fitted with a blank untreated disc. These discs sit above a fan that is powered by a small motor charged by solar energy. The device containing the untreated disc is not expected to prevent mosquito bites. The discs will still be replaced monthly for blinding purposes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Malaria prevalence	Malaria prevalence among children ≤ 5 years of age as determined by Rapid Diagnostic Test (RDT) positivity and confirmed by microscopy.	18 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of the diversionary effect of spatial repellent in the buffer zone using RDT and microscopy	Clusters are defined as discrete villages with a core and buffer zone. Buffer zones will be approximately 2km from the outer perimeter of the core zone and will not receive the intervention. This buffer zone will mitigate against the diversionary impact in the instance where villages are split into multiple clusters. The diversionary impact of the intervention on mosquitoes to locally unprotected individuals will be evaluated by measuring the malaria prevalence among children ≤ 5 years of age as determined by Rapid Diagnostic Test (RDT) positivity and confirmed by microscopy in a subset of households in the buffer zones. Mosquito population density and human biting rate will also be measured in the buffer zones.	18 months
Entomological correlates of transmission	Mosquito species composition and population density in mosquitoes caught using indoor CDC-light traps and Anopheline-human contact (indoor and outdoor) using human biting rate (HBR) as an indicator for all anophelines. Measured by human-landing catch (HLC).	18 months
Household surveys	Household surveys to collect information on subject behaviour related to exposure to malaria and use of existing control tools	18 months
Air sampling	Quantification of the temporal changes in concentration of transfluthrin present in the air over the duration of its use and the impact of indoor temperature on the concentration	18 months
Safety of intervention	Safety of intervention through monitoring of adverse events (AEs) and serious adverse events (SAEs)	18 months
Acceptability survey	Acceptability of Mossie-GO in these communities	18 months

Collaborators and Investigators

• Sponsor: Africa Power Limited
• Collaborators: Malaria Consortium; ARCTECH INNOVATION LIMITED
• Investigators: Principal Investigator: Robert Jones, PhD, Arctech Innovation

Study record dates

Study Major Dates

• Study Start (Estimated): February 1, 2024
• Primary Completion (Estimated): September 1, 2025
• Study Completion (Estimated): September 1, 2025

Study Registration Dates

• First Submitted: January 4, 2024
• First Submitted That Met QC Criteria: January 22, 2024
• First Posted (Estimated): January 31, 2024

Study Record Updates

• Last Update Posted (Estimated): January 31, 2024
• Last Update Submitted That Met QC Criteria: January 22, 2024
• Last Verified: January 1, 2024

More Information

Terms related to this study

• Keywords: malaria; vector control; randomised control trial; transfluthrin; spatial repellent
• Additional Relevant MeSH Terms: Infections; Parasitic Diseases; Protozoan Infections; Malaria; Vector Borne Diseases
• Other Study ID Numbers: 1577

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No