Dataset Information

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.

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.

SUBMITTER: Alonso S

PROVIDER: S-EPMC7948350 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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 Sergi S Chaccour Carlos J CJ Wagman Joseph J Candrinho Baltazar B Muthoni Rodaly R Saifodine Abuchahama A Saute Francisco F Robertson Molly M Zulliger Rose R

Malaria journal 20210310 1

<h4>Background</h4>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.<h4>Methods</h4>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 ...[more]

PMID: 33691706

Similar Datasets

Project description:BackgroundMost of the reduction in malaria prevalence seen in Africa since 2000 has been attributed to vector control interventions. Yet increases in the distribution and intensity of insecticide resistance and higher costs of newer insecticides pose a challenge to sustaining these gains. Thus, endemic countries face challenging decisions regarding the choice of vector control interventions.MethodsA cluster randomised trial is being carried out in Mopeia District in the Zambezia Province of Mozambique, where malaria prevalence in children under 5 is high (68% in 2015), despite continuous and campaign distribution of long-lasting insecticide-treated nets (LLINs). Study arm 1 will continue to use the standard, LLIN-based National Malaria Control Programme vector control strategy (LLINs only), while study arm 2 will receive indoor residual spraying (IRS) once a year for 2 years with a microencapsulated formulation of pirimiphos-methyl (Actellic 300 CS), in addition to the standard LLIN strategy (LLINs+IRS). Prior to the 2016 IRS implementation (the first of two IRS campaigns in this study), 146 clusters were defined and stratified per number of households. Clusters were then randomised 1:1 into the two study arms. The public health impact and cost-effectiveness of IRS intervention will be evaluated over 2 years using multiple methods: (1) monthly active malaria case detection in a cohort of 1548 total children aged 6-59 months; (2) enhanced passive surveillance at health facilities and with community health workers; (3) annual cross-sectional surveys; and (4) entomological surveillance. Prospective microcosting of the intervention and provider and societal costs will be conducted. Insecticide resistance status pattern and changes in local Anopheline populations will be included as important supportive outcomes.DiscussionBy evaluating the public health impact and cost-effectiveness of IRS with a non-pyrethroid insecticide in a high-transmission setting with high LLIN ownership, it is expected that this study will provide programmatic and policy-relevant data to guide national and global vector control strategies.Trial registration numberNCT02910934.

Project description:BackgroundThe need to develop new products and novel approaches for malaria vector control is recognized as a global health priority. One approach to meeting this need has been the development of new products for indoor residual spraying (IRS) with novel active ingredients for public health. While initial results showing the impact of several of these next-generation IRS products have been encouraging, questions remain about how to best deploy them for maximum impact. To help address these questions, a 2-year cluster-randomized controlled trial to measure the impact of IRS with a microencapsulated formulation of pirimiphos-methyl (PM) in an area with high ownership of long-lasting insecticidal nets (LLINs) was conducted in a high-transmission district of central Mozambique with pyrethroid resistant vectors. Presented here are the results of the vector surveillance component of the trial.MethodsThe 2 year, two-armed trial was conducted in Mopeia District, Zambezia Province, Mozambique. In ten sentinel villages, five that received IRS with PM in October-November 2016 and again in October-November 2017 and five that received no IRS, indoor light trap collections and paired indoor-outdoor human landing collections catches (HLCs) were conducted monthly from September 2016 through October 2018. A universal coverage campaign in June 2017, just prior to the second spray round, distributed 131,540 standard alpha-cypermethrin LLINs across all study villages and increased overall net usage rates in children under 5 years old to over 90%.ResultsThe primary malaria vector during the trial was Anopheles funestus sensu lato (s.l.), and standard World Health Organization (WHO) tube tests with this population indicated variable but increasing resistance to pyrethroids (including alpha-cypermethrin, from > 85% mortality in 2017 to 7% mortality in 2018) and uniform susceptibility to PM (100% mortality in both years). Over the entire duration of the study, IRS reduced An. funestus s.l. densities by 48% (CI95 33-59%; p < 0.001) in indoor light traps and by 74% (CI95 38-90%; p = 0.010) during indoor and outdoor HLC, though in each study year reductions in vector density were consistently greatest in those months immediately following the IRS campaigns and waned over time. Overall there was no strong preference for An. funestus to feed indoors or outdoors, and these biting behaviours did not differ significantly across study arms: observed indoor-outdoor biting ratios were 1.10 (CI95 1.00-1.21) in no-IRS villages and 0.88 (CI95 0.67-1.15) in IRS villages. The impact of IRS was consistent in reducing HLC exposures both indoors (75% reduction: CI95 47-88%; p = 0. < 0.001) and outdoors (68% reduction: CI95 22-87%; p = 0.012). While substantially fewer Anopheles gambiae s.l. were collected during the study, trends show a similar impact of IRS on this key vector group as well, with a 33% (CI95 7-53%; p = 0.019) reduction in mosquitoes collected in light traps and a non-statistically significant 39% reduction (p = 0.249) in HLC landing rates.ConclusionIRS with PM used in addition to pyrethroid-only LLINs substantially reduced human exposures to malaria vectors during both years of the cluster-randomized controlled trial in Mopeia-a high-burden district where the primary vector, An. funestus s.l., was equally likely to feed indoors or outdoors and demonstrated increasing resistance to pyrethroids. Findings suggest that IRS with PM can provide effective vector control, including in some settings where pyrethroid-only ITNs are widely used. Trial registration clinicaltrials.gov , NCT02910934. Registered 22 September 2016, https://www.clinicaltrials.gov/ct2/show/NCT02910934.

Project description:BackgroundInsecticide-treated nets (ITNs) and indoor residual spraying (IRS) of houses provide effective malaria transmission control. There is conflicting evidence about whether it is more beneficial to provide both interventions in combination. A cluster randomised controlled trial was conducted to investigate whether the combination provides added protection compared to ITNs alone.Methods and findingsIn northwest Tanzania, 50 clusters (village areas) were randomly allocated to ITNs only or ITNs and IRS. Dwellings in the ITN+IRS arm were sprayed with two rounds of bendiocarb in 2012. Plasmodium falciparum prevalence rate (PfPR) in children 0.5-14 y old (primary outcome) and anaemia in children <5 y old (secondary outcome) were compared between study arms using three cross-sectional household surveys in 2012. Entomological inoculation rate (secondary outcome) was compared between study arms. IRS coverage was approximately 90%. ITN use ranged from 36% to 50%. In intention-to-treat analysis, mean PfPR was 13% in the ITN+IRS arm and 26% in the ITN only arm, odds ratio = 0.43 (95% CI 0.19-0.97, n = 13,146). The strongest effect was observed in the peak transmission season, 6 mo after the first IRS. Subgroup analysis showed that ITN users were additionally protected if their houses were sprayed. Mean monthly entomological inoculation rate was non-significantly lower in the ITN+IRS arm than in the ITN only arm, rate ratio = 0.17 (95% CI 0.03-1.08).ConclusionsThis is the first randomised trial to our knowledge that reports significant added protection from combining IRS and ITNs compared to ITNs alone. The effect is likely to be attributable to IRS providing added protection to ITN users as well as compensating for inadequate ITN use. Policy makers should consider deploying IRS in combination with ITNs to control transmission if local ITN strategies on their own are insufficiently effective. Given the uncertain generalisability of these findings, it would be prudent for malaria control programmes to evaluate the cost-effectiveness of deploying the combination.Trial registrationwww.ClinicalTrials.gov NCT01697852 Please see later in the article for the Editors' Summary.

Project description:Malaria control today is threatened by widespread insecticide resistance in vector populations. The World Health Organization (WHO) recommends the use of a mixture of unrelated insecticides for indoor residual spraying (IRS) and long-lasting insecticidal nets (LNs) or as a combination of interventions for improved vector control and insecticide resistance management. Studies investigating the efficacy of these different strategies are necessary.The efficacy of Interceptor® G2 LN, a newly developed LN treated with a mixture of chlorfenapyr (a pyrrole) and alpha-cypermethrin (a pyrethroid), was compared to a combined chlorfenapyr IRS and Interceptor® LN (a standard alpha-cypermethrin LN) intervention in experimental huts in Cove Southern Benin, against wild, free-flying, pyrethroid-resistant Anopheles gambiae s.l. A direct comparison was also made with a pyrethroid-only net (Interceptor® LN) alone and chorfenapyr IRS alone.WHO resistance bioassays performed during the trial demonstrated a pyrethroid resistance frequency of >90% in the wild An. gambiae s.l. from the Cove hut site. Mortality in the control (untreated net) hut was 5%. Mortality with Interceptor® LN (24%) was lower than with chlorfenapyr IRS alone (59%, P < 0.001). The combined Interceptor® LN and chlorfenapyr IRS intervention and the mixture net (Interceptor® G2 LN) provided significantly higher mortality rates (73 and 76%, respectively) and these did not differ significantly between both treatments (P = 0.15). Interceptor LN induced 46% blood-feeding inhibition compared to the control untreated net, while chlorfenapyr IRS alone provided none. Both mixture/combination strategies also induced substantial levels of blood-feeding inhibition (38% with combined interventions and 30% with Interceptor® G2 LN). A similar trend of improved mortality of pyrethroid-resistant An. gambiae s.l. from Cove was observed with Interceptor® G2 LN (79%) compared to Interceptor LN (42%, P < 0.001) in WHO tunnel tests.The use of chlorfenapyr and alpha-cypermethrin together as a mixture on nets (Interceptor® G2 LN) or a combined chlorfenapyr IRS and pyrethroid LN intervention provides improved control of pyrethroid-resistant malaria vectors by inducing significantly higher levels of mortality through the chlorfenapyr component and providing personal protection through the pyrethroid component. Both strategies are comparable in their potential to improve the control of malaria transmitted by pyrethroid resistant mosquito vectors.

Project description:BackgroundDespite widespread use of long-lasting insecticidal nets (LLINs) and other tools, malaria caused 409,000 deaths worldwide in 2019. While indoor residual spraying (IRS) is an effective supplement, IRS is moderately expensive and logistically challenging. In endemic areas, IRS requires yearly application just before the main rainy season and potential interim reapplications. A new technology, insecticide-treated wall liner (ITWL), might overcome these challenges.MethodsWe conducted a 44-cluster two-arm randomized controlled trial in Muheza, Tanzania from 2015 to 2016 to evaluate the cost and efficacy of a non-pyrethroid ITWL to supplement LLINs, analyzing operational changes over three installation phases. The estimated efficacy (with 95% confidence intervals) of IRS as a supplement to LLINs came mainly from a published randomized trial in Muleba, Tanzania. We obtained financial costs of IRS from published reports and conducted a household survey of a similar IRS program near Muleba to determine household costs. The costs of ITWL were amortized over its 4-year expected lifetime and converted to 2019 US dollars using Tanzania's GDP deflator and market exchange rates.ResultsOperational improvements from phases 1 to 3 raised ITWL coverage from 35.1 to 67.1% of initially targeted households while reducing economic cost from $34.18 to $30.56 per person covered. However, 90 days after installing ITWL in 5666 households, the randomized trial was terminated prematurely because cone bioassay tests showed that ITWL no longer killed mosquitoes and therefore could not prevent malaria. The ITWL cost $10.11 per person per year compared to $5.69 for IRS. With an efficacy of 57% (3-81%), IRS averted 1162 (61-1651) disability-adjusted life years (DALYs) per 100,000 population yearly. Its incremental cost-effectiveness ratio (ICER) per DALY averted was $490 (45% of Tanzania's per capita gross national income).ConclusionsThese findings provide design specifications for future ITWL development and implementation. It would need to be efficacious and more effective and/or less costly than IRS, so more persons could be protected with a given budget. The durability of a previous ITWL, progress in non-pyrethroid tools, economies of scale and competition (as occurred with LLINs), strengthened community engagement, and more efficient installation and management procedures all offer promise of achieving these goals. Therefore, ITWLs merit ongoing study.First posted2015 ( NCT02533336 ).

Dataset Information

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.

Background

Methods

Results

Conclusion

Trial registration

Publications

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.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets