Title
Malaria High-Risk Populations in Namibia
Targeting Malaria High-risk Populations With Tailored Intervention Packages: A Study to Assess Feasibility and Effectiveness in Northern Namibia
Phase
Phase 4Lead Sponsor
University of California, San FranciscoStudy Type
InterventionalStatus
Completed No Results PostedIndication/Condition
MalariaIntervention/Treatment
Presumptive treatment with Artemether-lumefantrine (AL) [artemether (112966), lumefantrine (110582)] ...Study Participants
3302This study aims to determine the effectiveness, cost-effectiveness, acceptability, and feasibility of targeted delivery of a package of malaria interventions for improving effective coverage and reducing Plasmodium falciparum malaria transmission among malaria high-risk populations in Northern Namibia. Previous research identified cattle herders and agricultural workers as populations at higher risk of infection. The investigators hypothesize that targeted delivery of interventions will lead improve coverage in these groups and lead to a reduction in P. falciparum transmission.
This study is the second phase of work in Zambezi and Ohangwena Regions, Namibia, building off a formative phase of work that characterized the risk behaviors migratory patterns, health-seeking behaviors, intervention strategies and social networks of agricultural workers and cattle herders, who are previously identified malaria high-risk populations (HRPs). This phase of the study now aims to determine the effectiveness, cost-effectiveness, acceptability, and feasibility of targeted delivery of a package of malaria interventions for improving effective coverage and reducing Plasmodium falciparum malaria transmission in these regions among these populations.
The study will specifically assess the coverage and impact of interventions delivered at worksites to HRPs, including presumptive treatment administered alongside vector control interventions (indoor residual spraying [IRS], long-lasting insecticidal nets [LLINs], and topical repellents). The effectiveness of these interventions will be compared against areas with no study interventions (standard of care) over the course of implementation (November 2019 - May 2020). Primary outcomes will include the coverage of each intervention at worksites over the study period and PCR-based P. falciparum prevalence measured at endline. Following a baseline cross-sectional survey in November/December 2019, the interventions will consist of 2 rounds of presumptive treatment spaced at least one month apart between January and March, and delivery of vector control interventions at worksites and key access points with support from employers, with the primary evaluation to be conducted through an endline cross-sectional survey in April/May 2020. Secondary outcomes around effectiveness will be assessed through incident case data providing measures of incidence in HRP and non-HRP populations, odds of infection associated with each intervention in cases compared to controls and entomological data collection. In addition, operational and feasibility outcomes will be assessed through qualitative data collection, population size estimation of HRP groups and a global positioning system (GPS) logger study.
All eligible HRPs will be presumptively treated with artemether-lumefantrine (AL) at two timepoints, separated by at least one month. All individuals who have provided informed consent, meet eligibility criteria, are not pregnant or breastfeeding, and who do not have symptoms associated with severe malaria or another severe illness, will be offered an age-appropriate course of AL (age-specific blister packages). AL is currently the first line drug used for uncomplicated malaria in Namibia, and has been used previously in northern Namibia for focal mass drug administration and has no severe adverse effects and is well-tolerated, with high adherence and acceptability in this context. AL requires two daily doses for three consecutive days, for a total of six doses. The first antimalarial dose will be delivered by directly observed therapy (DOT) and subsequent doses will be left with the subject, with instructions to self-administer them.
The mop up indoor residual spraying (IRS) campaign will be targeted to farms and cattle posts/kraals in intervention areas in December 2019 to fill gaps from the routine spray campaign (September to November 2019) and utilize the same insecticides and protocols as the national campaign. The team will spray each unsprayed structure with the recommended solution of dichloro-diphenyl-trichloroethane (DDT) for traditional structures and/or Actellic for modern structures, tarps and tents. Alternative vector control interventions, including LLINs (long-lasting insecticide treated bed nets), sprayed tents/tarps and topical repellents will be distributed to eligible HRPs between November and January 2020 during one round.
For all eligible HRPs in intervention areas, after obtaining informed consent, presumptive treatment for malaria will be carried out using artemether-lumefantrine (AL) at two time points. Enhanced vector control activities will include: (1) a mop up indoor residual spraying (IRS) campaign and (2) distribution of long-lasting insecticide-treated nets (LLINs) and/or vector control packs with topical repellent. The intervention arm will also receive the standard of care in Namibia.
The control arm will receive the standard of care in Namibia: passive case detection through health facilities and health extension workers, routine indoor residual spraying (IRS), and reactive case detection (RACD) accompanied by reactive IRS.
Inclusion Criteria: HRP study populations (all) Study participants include those in the 8 selected health facility catchment areas within Zambezi and Ohangwena Regions. Identify primary occupation as a agricultural worker or cattle herder Zambezi Region: Have slept or worked outside at a farm or cattle post in the past 7 days or will do over the next 3 weeks (sleeping outside, working outside ploughing or guarding crops/cattle, or sleeping in any type of structure located at a farm or cattle post site) Ohangwena Region: Report overnight travel to Angola for grazing cattle during the malaria transmission season (November to May) Be willing and able to provide consent (ie mentally fit) Inclusion Criteria: Presumptive AL treatment In addition to the above, subjects must report travel outside of Namibia within the past 60 days to be eligible to receive AL. Inclusion Criteria: Enhanced vector control In addition to the above, participants must not sleep in a structure sprayed with insecticide to be eligible to receive an LLIN or sprayed tent/tarp. Inclusion Criteria: Focus group discussions and key informant interviews Meet eligibility criteria as a member of an HRP, health facility staff or health extension worker involved in the diagnosis and treatment of HRP populations. Individuals must be 18 years and older and willing and able to provide consent to be included in the GPS logger, focus group discussions or key informant interviews Exclusion Criteria: Per national guidelines in Namibia, presumptive treatment with AL will not be given to women who are pregnant in the first trimester, individuals weighing less than 5kg, those with a known AL allergy or suspected severe malaria. Individuals under the age of 18 will be excluded from the GPS logger study, focus group discussions and key informant interviews.
