Cost and cost-effectiveness of indoor residual spraying with pirimiphos-methyl in a high malaria transmission district of Mozambique with high access to standard insecticide-treated nets

Alonso, S., Chaccour, C. J., Wagman, J., Candrinho, B., Muthoni, R., Saifodine, A., Saute, F., Robertson, M. and Zulliger, R. (2021) Cost and cost-effectiveness of indoor residual spraying with pirimiphos-methyl in a high malaria transmission district of Mozambique with high access to standard insecticide-treated nets. Malaria Journal, 20(1), 143. (doi: 10.1186/s12936-021-03687-1) (PMID:33691706) (PMCID:PMC7948350)

Abstract

Background: As malaria cases increase in some of the highest burden countries, more strategic deployment of new and proven interventions must be evaluated to meet global malaria reduction goals. Methods: The cost and cost-effectiveness of indoor residual spraying (IRS) with pirimiphos-methyl (Actellic®300 CS) were assessed in a high transmission district (Mopeia) with high access to pyrethroid insecticide-treated nets (ITNs), compared to ITNs alone. The major mosquito vectors in the area were susceptible to primiphos-methyl, but resistant to pyrethoids. A decision analysis approach was followed to conduct deterministic and probabilistic sensitivity analyses in a theoretical cohort of 10,000 children under five years of age (U5) and 10,000 individuals of all ages, separately. Model parameters and distributions were based on prospectively collected cost and epidemiological data from a cluster-randomized control trial and a literature review. The primary analysis used health facility-malaria incidence, while community cohort incidence and cross-sectional prevalence rates were used in sensitivity analyses. Lifetime costs, malaria cases, deaths and disability-adjusted life-years (DALYs) were calculated to determine the incremental costs per DALY averted through IRS. Results: The average IRS cost per person protected was US$8.26 and 51% of the cost was insecticide. IRS averted 46,609 (95% CI 46,570–46,646) uncomplicated and 242 (95% CI 241–243) severe lifetime cases in a theoretical children U5 cohort, yielding an incremental cost-effectiveness ratio (ICER) of US$400 (95% CI 399–402) per DALY averted. In the all-age cohort, the ICER was higher: US$1,860 (95% CI 1,852–1,868) per DALY averted. Deterministic and probabilistic results were consistent. When adding the community protective effect of IRS, the cost per person protected decreased (US$7.06) and IRS was highly cost-effective in children U5 (ICER = US$312) and cost-effective in individuals of all ages (ICER = US$1,431), compared to ITNs alone. Conclusion: This study provides robust evidence that IRS with pirimiphos-methyl can be cost-effective in high transmission regions with high pyrethroid ITN coverage where the major vector is susceptible to pirimiphos-methyl but resistant to pyrethroids. The finding that insecticide cost is the main driver of IRS costs highlights the need to reduce the insecticide price without jeopardizing effectiveness. Trial registration: ClinicalTrials.gov identifier NCT02910934 (Registered 22 September 2016). https://clinicaltrials.gov/ct2/show/NCT02910934?term=NCT02910934&draw=2&rank=1

• Item Type: Articles
• Additional Information: Funding for this study was provided by USAID through the US President’s Malaria Initiative (PMI) and by UNITAID through its Next Generation IRS grant to the IVCC-lead consortium, under which PATH is responsible for leading evidence work. CISM is supported by the Government of Mozambique and the Spanish Agency for International Development (AECID). ISGlobal is supported by the Generalitat de Catalunya through the CERCA Programme; and the Spanish Ministry of Science, Innovation and Universities through the “Centro de Excelencia Severo Ochoa 2019–2023” Programme (CEX2018-000,806-S). CCh was supported by a Ramón Areces Fellowship. RZ and AS are supported by PMI funds.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Alonso, Dr Sergi
• Authors: Alonso, S., Chaccour, C. J., Wagman, J., Candrinho, B., Muthoni, R., Saifodine, A., Saute, F., Robertson, M., and Zulliger, R.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Malaria Journal
• Publisher: BMC
• ISSN: 1475-2875
• ISSN (Online): 1475-2875
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Malaria Journal 20(1):143
• Publisher Policy: Reproduced under a Creative Commons License