Strategies implemented since 2010 by the Senegalese National Malaria Control Program (NMCP) enabled a reduction of malaria transmission. However, malaria incidence increased again in recent years, especially in the "red zone" of Kedougou, Kolda and Tambacounda regions. Neighbouring Sahelian countries also documented an increase in malaria incidence in the same period. Current interventions include : long-lasting insecticidal nets, free diagnostic and treatment of clinical malaria, home-based case management (PECADOM), intermittent preventive treatment of pregnant women and seasonal malaria chemoprevention for children up to 10 years. These strategies, while efficient to reduce the burden of clinical malaria, do not account for individuals chronically infected with Plasmodium parasites. These carriers often remain asymptomatic and act as a reservoir for persistence during the dry season, and onwards transmission during the wet season. An observational study conducted in Kedougou in 2021 and 2022 by IRD Dakar shed light on the most affected age groups and on risk-factors associated with asymptomatic carriage. Interventions against asymptomatic carriage could complement existing strategies and contribute to reducing malaria transmission. Mass drug administration (MDA) involves proposing a curative treatment of each member of the community, regardless of age, during a coordinated campaign. To this day, it is the only intervention available to deplete the reservoir of Plasmodium carriers, since a large proportion of asymptomatic infections remain undetectable with available field tests. A study conducted by NMCP and Iba Der Thiam University in Thiès (UIDT) in 2021 in Tambacounda showed that regular MDA campaigns during the high transmission season had a significant impact on clinical malaria incidence and on prevalence of carriage. AMARETi project aims to evaluate an intervention to complete current control strategies. The design of this intervention combines the recent results from Kedougou and Tambacounda studies. The intervention consists of an MDA campaign at the start and at the end of the high transmission season, aiming at maximal depletion of the asymptomatic reservoir, and of age-group targeted interventions aiming to reduce chronic reinfection in individuals at highest risk of asymptomatic carriage. The design and implementation of the intervention stem from a co-construction process with members of communities participating in the research, to maximize inclusiveness and adhesion. It aims to ensure the design of interventions that are adapted to age, gender and other factors deemed relevant by researchers and communities. The project will evaluate if this intervention improves significantly the situation compared to current strategy in a stepped-wedge cluster-randomized controlled trial over 2 malaria high transmission seasons. If the results are conclusive, recommendations for scale-up can be made. The primary outcome will be Plasmodium falciparum infection prevalence at the end of the high transmission season. Secondary outcomes include clinical malaria incidence and malaria incidence dynamics, as well as participation, safety and acceptability. Implementation outcomes (not detailed here) will include the assessment of implementation (CFIR's indicators), sustainability (Schell's indicators) and scalability (Coroa's indicators). These indicators use multiple dimensions stemming from qualitative and quantitative data and flexible design to understand each specific outcome (Proctor E, et al, Mental Health and Mental Health Services Research 2011). In addition, a nested study in 10 villages will provide insights on transmission and reservoir restoration mechanisms through follow-up of a cohort and in-depth investigations. AMARETi project will take place from 2024 to 2027 in 7 health posts and 50 villages of Kedougou department, under the leadership of the Kedougou Health District and Region authorities. The local health, administrative and community-based authorities at local and regional level are also key partners in the project, as well as local development committees and health community-based organisations. Healthpost staff and community health workers and volunteers will be essential for the operational field implementation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
18,000
MDA: 2 rounds of MDA with dihydroartemisinine-piperaquine + single low dose primaquine (PQ) administered instead of SMC round 1 and 5.
Communication and community engagement activities by age-groups: * children aged 10-14 and their parents : promote early health seeking behaviour in case of symptoms * young adults (15-24) : promote early health seeking behaviour in case of symptoms, emphasing the importance of mild symptoms.
Voluntary testing for malaria in young adults (15-24 years) using rapid diagnostic tests performed by community health workers during home visits or group testing events organized by the village youth association.
District de Santé de Kédougou - Kedougou Health District
Kédougou, Senegal
Plasmodium falciparum carriage reservoir at the end of the high transmission season (step 0)
Number of participants with P. falciparum infection (measured by qPCR in cross sectional sample). Survey conducted at step 0 (baseline, year 0, no intervention). Survey takes place 4 months after SMC round 1 i.e. immediately before SMC round 5.
Time frame: 4 months after SMC round 1, baseline year 0
Plasmodium falciparum carriage reservoir at the end of the high transmission season (step 1)
Number of participants with P. falciparum infection (measured by qPCR in cross sectional sample). Surveys conducted at step 1 (year 1, intervention in 50% of clusters). Survey takes place 4 months after SMC round 1 in control villages (i.e. immediately before SMC round 5) and 4 months after MDA1 in intervention villages (i.e. immediately before MDA2).
Time frame: 4 months after MDA1/SMC round 1, year 1
Plasmodium falciparum carriage reservoir at the end of the high transmission season (step 2)
Number of participants with P. falciparum infection (measured by qPCR in cross sectional sample). Surveys conducted at step 2 (year 2). During the final step, intervention MDA3 (at the start of the wet season, replacing SMC round 1) and MDA4 (at the end of the wet season, replacing SMC round 5) take place in all clusters. Survey takes place 4 months after MDA3 in intervention villages (i.e. immediately before MDA4).
Time frame: 4 months after MDA3, year 2
Odds ratio of P. falciparum infection associated with intervention/control period status
The results of the cross sectional surveys at year 0, 1 and 2 (see outcomes 1-3) will be analysed in a multivariable multilevel logistic regression model. Explained variable : P. falciparum infection detected by qPCR. Variable of interest : intervention or control status at village level. Adjustments for individual, household, and cluster-level fixed effects. Including household, village, cluster and temporal random effects.
Time frame: 4 months after SMC round 1, years 0, 1 and 2
Clinical malaria burden
Cumulative P. falciparum clinical malaria incidence in study villages during the high transmission season (june to january) as recorded at community (CHW) and health-facility level. Comparison between intervention and control periods will evaluate burden reduction associated with intervention status.
Time frame: year 1, year 2
Spatio-temporal dynamics of clinical malaria incidence
Time-series of weekly cumulative incidence of clinical P. falciparum malaria recorded by CHW and health facilities in study villages during the high transmission season.
Time frame: year 1, year 2
Mass drug administration safety (active)
Frequency and severity of adverse events identified by active detection in a random sample of participants immediately after each MDA round.
Time frame: Day 4 after MDA start
Mass drug administration safety (passive)
Frequency and severity of adverse events recorded by passive detection at community (CHW) and health-facility level during each MDA (MDA1, 2, 3 and 4).
Time frame: Day 0 to day 7 after MDA start
Plasmodium falciparum carriage reservoir at the onset of the high transmission season (step 1)
Number of participants with P. falciparum infection (measured by qPCR in cross sectional sample). Survey conducted at step 1 (year 1, intervention in 50% of clusters). Survey takes place immediately before SMC round 1 in control villages and immediately before MDA1 in intervention villages. This period corresponds to the onset of the high transmission season (i.e. the end of the dry, low transmission season)
Time frame: immediately before MDA1/SMC round 1, year 1
Plasmodium falciparum carriage reservoir at the onset of the high transmission season (step 2)
Number of participants with P. falciparum infection (measured by qPCR in cross sectional sample). Surveys conducted at step 2 (year 2, intervention in 100% of clusters), immediately before MDA3, at the onset of the high transmission season (i.e. at the end of the dry, low transmission season)
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Time frame: immediately before MDA3, year 2
Plasmodium falciparum infection prevalence in 10-14 and 15-24 years
Number of participants aged 10-14 and 15-24 years with P. falciparum infection (measured by qPCR in cross sectional sample). Surveys conducted at step 1 (year 1, intervention in 50% of clusters). Survey takes place 4 months after SMC round 1 in control villages (i.e. immediately before SMC round 5) and 4 months after MDA1 in intervention villages (i.e. immediately before MDA2). This subgroup analysis of secondary outcome 2 will enable comparison of prevalence and prevalence reduction between intervention and control periods by age-group to estimate potential effectiveness of the targeted control intervention.
Time frame: 4 months after SMC round 1 / MDA1, year 1
Plasmodium falciparum infection prevalence in 10-14 and 15-24 years
Number of participants aged 10-14 and 15-24 years with P. falciparum infection (measured by qPCR in cross sectional sample). Surveys conducted at step 2 (year 2, intervention in all clusters). Survey takes place 4 months after MDA3 (i.e. immediately before MDA4). This subgroup analysis of secondary outcome 3 will enable comparison of prevalence and prevalence reduction between intervention and control periods by age-group to estimate potential effectiveness of the targeted control intervention.
Time frame: 4 months after MDA3, year 2
Intervention cost-effectiveness
Intervention cost and cost-effectiveness ratio regarding prevalence reduction and clinical burden reduction
Time frame: year 2 and year 3
Participation to MDA intervention
Proportion of population participating to intervention relatively to total and eligible population, estimated for each MDA round (MDA1 to MDA4). 3-dose complete participation measured at the end of each MDA round, as well as incomplete participation (only 1 or 2 doses taken).
Time frame: Day 5 after MDA (MDA1 & MDA2, year 1; MDA2 & MDA3, year 2).
Participation to targeted control intervention (15-24 years)
Proportion of eligible 15-24 years old who completed at least one rapid diagnostic test during targeted control activities taking place from month 2 to month 3 after MDA1 during year 1 and from month 2 to month 3 after MDA3 during year 2.
Time frame: from month 2 to month 3 MDA1 (year 2) ; from month 2 to month 3 after MDA3 (year 2)
Intervention acceptability
Sekhon's indicators of acceptability evaluated using mixed methods (quantitative during cross-sectional surveys and qualitative) evaluated prospectively before MDA and retrospectively after MDA. Quantitative evaluation will rely on a -7 to +7 scale established combining responses to close-ended questions on the 7 dimensions of acceptability.
Time frame: after MDA, year 1