The Effectiveness of Reactive Focal Mass Drug Administration (rfMDA) and Reactive Focal Vector Control (RAVC) to Reduce Malaria Transmission: A Cluster-Randomised Controlled Open Label Two-by-Two Factorial Design Trial from the Low-Endemic Setting of Namibia

Hsiang, Michelle S.; Ntuku, Henry; Roberts, Kathryn W.; Dufour, Mi‐Suk Kang; Whittemore, Brooke; Tambo, Munyaradzi; McCreesh, Patrick; Medzihradsky, Oliver F.; Prach, Lisa M.; Siloka, Griffith; Siame, Noel; Smith-Gueye, Cara; Schrubbe, Leah; Wu, Lindsey; Scott, Valerie; Tessema, Sofonias K.; Greenhouse, Bryan; Erlank, Erica; Koekemoer, Lizette L.; Sturrock, Hugh J. W.; Mwilima, Agnes; Katokele, Stark; Uusiku, Petrina; Bennett, Adam; Smith, Jennifer L.; Kleinschmidt, Immo; Mumbengegwi, Davis R.; Gosling, Roly

doi:10.2139/ssrn.3454698

Cited by 3 publications

(12 citation statements)

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“…This mixed-methods study included key informant interviews (KIIs), focus group discussions (FGDs), and an endline cross-sectional survey, nested within the above described cluster-randomized controlled trial [9,18]. The qualitative assessment followed the theoretical framework of acceptability of Sekhon et al including: burden (reasons for dropout), ethical consequences (reported adverse events), experience (user satisfaction), affective attitude (attitude towards intervention), opportunity costs (influence on adherence and participation), and intention (willingness to participate) [22].…”

Section: Methodsmentioning

confidence: 99%

“…For the quantitative acceptability assessment, refusal rates were measured during trial implementation and willingness to participate in future interventions was assessed in 2017 in an endline cross-sectional survey. The sampling and methods of this survey have been described previously [9]. The survey was powered to detect anticipated differences in trial outcomes.…”

Section: Methodsmentioning

confidence: 99%

“…The acceptability study occurred during 2015 (pretrial), 2016, and 2017 (years 1 and 2 of the trial). While data from 2016 were not included in the main trial analysis [9], the qualitative data from both years are included here, as interventions did not change year to year.…”

Section: Trial Contextmentioning

confidence: 99%

“…Reactive vector control (RAVC), in the form of indoor residual spraying (IRS), targets the mosquito and reduces human-mosquito contact. The effectiveness of rfMDA versus RACD, RAVC versus no RAVC, and rfMDA + RAVC versus RACD only, were compared in a two-by-two factorial design cluster randomized controlled trial [9] In adjusted analyses, rfMDA and RAVC implemented over a one-year period with over 80% coverage decreased malaria incidence by 48 and 52%, respectively, with their combination decreasing incidence by 74%.…”

Section: Introductionmentioning

confidence: 99%

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Community acceptance of reactive focal mass drug administration and reactive focal vector control using indoor residual spraying, a mixed‐methods study in Zambezi region, Namibia

Roberts¹,

Gueye²,

Baltzell³

et al. 2021

Malar J

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Background In Namibia, as in many malaria elimination settings, reactive case detection (RACD), or malaria testing and treatment around index cases, is a standard intervention. Reactive focal mass drug administration (rfMDA), or treatment without testing, and reactive focal vector control (RAVC) in the form of indoor residual spraying, are alternative or adjunctive interventions, but there are limited data regarding their community acceptability. Methods A parent trial aimed to compare the effectiveness of rfMDA versus RACD, RAVC versus no RAVC, and rfMDA + RAVC versus RACD only. To assess acceptability of these interventions, a mixed-methods study was conducted using key informant interviews (KIIs) and focus group discussions (FGDs) in three rounds (pre-trial and in years 1 and 2 of the trial), and an endline survey. Results In total, 17 KIIs, 49 FGDs were conducted with 449 people over three annual rounds of qualitative data collection. Pre-trial, community members more accurately predicted the level of community acceptability than key stakeholders. Throughout the trial, key participant motivators included: malaria risk perception, access to free community-based healthcare and IRS, and community education by respectful study teams. RACD or rfMDA were offered to 1372 and 8948 individuals in years 1 and 2, respectively, and refusal rates were low (< 2%). RAVC was offered to few households (n = 72) in year 1. In year 2, RAVC was offered to more households (n = 944) and refusals were < 1%. In the endline survey, 94.3% of 2147 respondents said they would participate in the same intervention again. Conclusions Communities found both reactive focal interventions and their combination highly acceptable. Engaging communities and centering and incorporating their perspectives and experiences during design, implementation, and evaluation of this community-based intervention was critical for optimizing study engagement.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Trial Contextmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Community acceptance of reactive focal mass drug administration and reactive focal vector control using indoor residual spraying, a mixed‐methods study in Zambezi region, Namibia

Roberts¹,

Gueye²,

Baltzell³

et al. 2021

Malar J

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“…Determining this geographical parameter largely follows an epidemiological and operational perspective (3,15,19). Epidemiological factors are defined according to local transmission, vector species, environment which determine the geographical boundaries used to identify those at risk or vulnerable to infection (20)(21)(22)(23). The operational factors pragmatically consider the ability of the local health systems to implement RACD in terms of availability of resources (funding, human resources) (3,15,18,24).…”

Section: Introductionmentioning

confidence: 99%

Complexities in Defining the Unit of Intervention for Reactive Community-Based Malaria Treatment in the Gambia

Jaiteh

Ribera

Masunaga

et al. 2021

Front. Public Health

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With significant declines in malaria, infections are increasingly clustered in households, or groups of households where malaria transmission is higher than in surrounding household/villages. To decrease transmission in such cases, reactive interventions target household members of clinical malaria cases, with the intervention unit (e.g., the “household/s”) derived from an epidemiological and operational perspective. A lack of unanimity regarding the spatial range of the intervention unit calls for greater importance to be placed on social context in conceptualizing the appropriate unit. A novel malaria elimination strategy based on reactive treatment was recently evaluated by a cluster randomized trial in a low transmission setting in The Gambia. Transdisciplinary research was used to assess and improve the effectiveness of the intervention which consisted, among others, of reflecting on whether the household was the most adequate unit of analysis. The intervention was piloted on the smallest treatment unit possible and was further adapted following a better understanding of the social and epidemiological context. Intervention units defined according to (i) shared sleeping spaces and (ii) household membership, showed substantial limitations as it was not possible to define them clearly and they were extremely variable within the study setting. Incorporating local definitions and community preference in the trial design led to the appropriate intervention unit—the compound—defined as an enclosed space containing one or several households belonging to the same extended patrilineal family. Our study demonstrates the appropriateness of using transdisciplinary research for investigating alternative intervention units that are better tailored to reactive treatment approaches.

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Targeted malaria elimination interventions reducePlasmodium falciparuminfections up to 3 kilometers away

Benjamin-Chung,

Li,

Nguyen

et al. 2023

Preprint

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Malaria elimination interventions in low-transmission settings aim to extinguish hot spots and prevent transmission to nearby areas. In malaria elimination settings, the World Health Organization recommends reactive, focal interventions targeted to the area near malaria cases shortly after they are detected. A key question is whether these interventions reduce transmission to nearby uninfected or asymptomatic individuals who did not receive interventions. Here, we measured direct effects (among intervention recipients) and spillover effects (among non-recipients) of reactive, focal interventions delivered within 500m of confirmed malaria index cases in a cluster-randomized trial in Namibia. The trial delivered malaria chemoprevention (artemether lumefantrine) and vector control (indoor residual spraying with Actellic) separately and in combination using a factorial design. We compared incidence, infection prevalence, and seroprevalence between study arms among intervention recipients (direct effects) and non-recipients (spillover effects) up to 3 km away from index cases. We calculated incremental cost-effectiveness ratios accounting for spillover effects. The combined chemoprevention and vector control intervention produced direct effects and spillover effects. In the primary analysis among non-recipients within 1 km from index cases, the combined intervention reduced malaria incidence by 43% (95% CI 20%, 59%). In secondary analyses among non-recipients 500m-3 km from interventions, the combined intervention reduced infection by 79% (6%, 95%) and seroprevalence 34% (20%, 45%). Accounting for spillover effects increased the cost-effectiveness of the combined intervention by 37%. Our findings provide the first evidence that targeting hot spots with combined chemoprevention and vector control interventions can indirectly benefit non-recipients up to 3 km away.

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The Effectiveness of Reactive Focal Mass Drug Administration (rfMDA) and Reactive Focal Vector Control (RAVC) to Reduce Malaria Transmission: A Cluster-Randomised Controlled Open Label Two-by-Two Factorial Design Trial from the Low-Endemic Setting of Namibia

Cited by 3 publications

References 0 publications

Community acceptance of reactive focal mass drug administration and reactive focal vector control using indoor residual spraying, a mixed‐methods study in Zambezi region, Namibia

Community acceptance of reactive focal mass drug administration and reactive focal vector control using indoor residual spraying, a mixed‐methods study in Zambezi region, Namibia

Complexities in Defining the Unit of Intervention for Reactive Community-Based Malaria Treatment in the Gambia

Targeted malaria elimination interventions reducePlasmodium falciparuminfections up to 3 kilometers away

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