Cost of Community-Led Larval Source Management and House Improvement for Malaria Control: A Cost Analysis Within A Cluster-Randomised Trial in A Rural District in Malawi
Background: House improvement (HI) to prevent mosquito house entry, and larval source management (LSM) targeting aquatic mosquito stages to prevent development into adult forms, are promising complementary interventions to current malaria vector control strategies. Lack of evidence on costs and cost-effectiveness of community-led implementation of HI and LSM has hindered wide scale adoption. This study presents an incremental cost analysis of community-led implementation of HI and LSM, in a factorial design trial, in addition to standard national malaria control interventions in Chikwawa district, southern Malawi.
Methods: In the trial, LSM comprised draining, filling, and Bacillus thuringiensis israelensis larvicide application, while HI involved closing of eaves and gaps on walls, and screening windows and ventilation spaces with wire mesh. Communities implemented all interventions. Costs were estimated retrospectively using the ‘ingredients approach’, combining both ‘bottom-up’ and ‘top-down approaches’, from the societal perspective. To estimate the cost of independently implementing each intervention arm, resources shared between trial arms (e.g. overheads) were allocated to each consuming arm using proxies developed based on share of resource input quantities consumed. Incremental implementation costs (in 2017 US$) are presented for HI only, LSM only and HI+LSM arms. In sensitivity analyses, the effect of varying costs of important inputs on estimated costs was explored.
Results: The total economic program costs of community-led HI and LSM implementation was $626,152. Economic implementation costs of HI, LSM and HI+LSM were estimated as $27.04, $25.06 and $33.44, per person per year, respectively. Staff, transport and labour costs, but not larvicide or screening material, were the major cost drivers across all interventions. Estimated costs were sensitive to changes in staff costs and population covered.
Conclusions: In the context of the trial, the economic costs of community-led HI and LSM implementation were high compared to conventional vector control interventions. Several factors, including the year-round implementation of LSM and low human population density could explain the high costs. The factorial trial design necessitated use of proxies to allocate costs shared between trial arms, which may limit generalisability of estimated costs where different designs are used. Nevertheless, costs may inform planners of future similar intervention packages.
Trial registration: Not applicable. The original trial was registered with The Pan African Clinical Trials Registry on 3 March 2016, trial number PACTR201604001501493.
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This is a list of supplementary files associated with this preprint. Click to download.
Additional File S1.docx: Staff structure, roles and time spent on intervention implementation of trial interventions.
Additional File S2.docx: Resource consumption shares for each trial intervention arm used to develop cost allocation proxies
Additional File S3.docx: Inflation, exchange and annualisation factors
Additional File S4.docx: Tornado graphs and sensitivity analysis of the mean cost per person for larval source management alone arm and house improvement plus larval source management arm.
Posted 22 Dec, 2020
Received 12 Jan, 2021
On 23 Dec, 2020
Invitations sent on 23 Dec, 2020
On 23 Dec, 2020
On 17 Dec, 2020
On 17 Dec, 2020
On 17 Dec, 2020
On 16 Dec, 2020
Cost of Community-Led Larval Source Management and House Improvement for Malaria Control: A Cost Analysis Within A Cluster-Randomised Trial in A Rural District in Malawi
Posted 22 Dec, 2020
Received 12 Jan, 2021
On 23 Dec, 2020
Invitations sent on 23 Dec, 2020
On 23 Dec, 2020
On 17 Dec, 2020
On 17 Dec, 2020
On 17 Dec, 2020
On 16 Dec, 2020
Background: House improvement (HI) to prevent mosquito house entry, and larval source management (LSM) targeting aquatic mosquito stages to prevent development into adult forms, are promising complementary interventions to current malaria vector control strategies. Lack of evidence on costs and cost-effectiveness of community-led implementation of HI and LSM has hindered wide scale adoption. This study presents an incremental cost analysis of community-led implementation of HI and LSM, in a factorial design trial, in addition to standard national malaria control interventions in Chikwawa district, southern Malawi.
Methods: In the trial, LSM comprised draining, filling, and Bacillus thuringiensis israelensis larvicide application, while HI involved closing of eaves and gaps on walls, and screening windows and ventilation spaces with wire mesh. Communities implemented all interventions. Costs were estimated retrospectively using the ‘ingredients approach’, combining both ‘bottom-up’ and ‘top-down approaches’, from the societal perspective. To estimate the cost of independently implementing each intervention arm, resources shared between trial arms (e.g. overheads) were allocated to each consuming arm using proxies developed based on share of resource input quantities consumed. Incremental implementation costs (in 2017 US$) are presented for HI only, LSM only and HI+LSM arms. In sensitivity analyses, the effect of varying costs of important inputs on estimated costs was explored.
Results: The total economic program costs of community-led HI and LSM implementation was $626,152. Economic implementation costs of HI, LSM and HI+LSM were estimated as $27.04, $25.06 and $33.44, per person per year, respectively. Staff, transport and labour costs, but not larvicide or screening material, were the major cost drivers across all interventions. Estimated costs were sensitive to changes in staff costs and population covered.
Conclusions: In the context of the trial, the economic costs of community-led HI and LSM implementation were high compared to conventional vector control interventions. Several factors, including the year-round implementation of LSM and low human population density could explain the high costs. The factorial trial design necessitated use of proxies to allocate costs shared between trial arms, which may limit generalisability of estimated costs where different designs are used. Nevertheless, costs may inform planners of future similar intervention packages.
Trial registration: Not applicable. The original trial was registered with The Pan African Clinical Trials Registry on 3 March 2016, trial number PACTR201604001501493.
Figure 1
Figure 2
Figure 3
Figure 4