MALARIA ELIMINATION IN ZANZIBAR - Soper Strategies

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INDOOR RESIDUAL SPRAYING As noted above, IRS under sustained control includes full coverage for two years, followed by three years of targeted spraying in malaria “hot spots” (North B, Central and Micheweni districts), followed by focal spraying of clusters if an outbreak is detected. For costing purposes, we consider “targeted spraying” to be the equivalent of 20% of households and “focal spraying” to be the equivalent of 10% of households per year. An IRS program under elimination would be very similar, with the additional assumption that focal spraying would decline to zero under the elimination scenarios due to a reduction in the number of foci to be treated. 1 Since IRS is withdrawn in the short-term for both sustained control and elimination, it is not included in the long-term costing of both phases. However, a recent review suggests that a combination of IRS with LLINs provides a higher protective effect than both of the interventions implemented individually. If the recently documented reduction in malaria burden on Zanzibar is indeed due to a combined effect of IRS and LLINs, sustained control will require continuation of both interventions, making it on average 40% more expensive compared to the sustained control scenario assumed in this analysis. This addition would change the cost comparison between sustained control and elimination, potentially resulting in elimination being cost saving in the short- to medium-term. DIAGNOSIS & TREATMENT There are four major differences between the diagnosis and treatment approaches under sustained control and elimination: 1. Testing of all fever or history of fever cases: While this is also recommended under sustained control, the elimination scenarios assume almost universal health seeking behavior for fever and testing rates over time. This results in a continuous increase of the number of RDTs needed and makes RDTs the main cost driver of case management for elimination. 70 2. Inclusion of formal private sector: Under sustained control, the program’s objective is to test every febrile client in the public sector for malaria and treat all positive cases with ACT. The elimination program will need to expand this to include testing and appropriate treatment of all fever cases in the private sector as well. This will be a challenging policy to enforce and will likely require that the government provide ACTs and RDTs free to private sector facilities to encourage compliance. 3. Treatment only in formal facilities: Since it is imperative that all malaria cases be captured by the surveillance system and appropriately addressed, the ZMCP will need to ensure that all fever cases are tested and treated in formal health facilities, including the many patients that currently seek treatment in the informal private sector. This will further increase costs 1 It is important to note that some continued costs of IRS under elimination are built into the costing of surveillance, as input costs for outbreak response. related to ACTs and RDTs because a higher fraction of the population will be treated in facilities than under sustained control. 4. Quality assurance with PCR: Unlike sustained control, it is recommended that an elimination program include use of PCR to consistently check the quality of RDT diagnosis conducted in peripheral facilities. The recommended approach would PCR test every positive test and 10% of negative RDTs and blood smears collected from the public and private sectors. The starting point for this analysis (including treatment seeking behavior, diagnosis rates, etc.) is taken from Zanzibar’s Roll Back Malaria Needs Assessment as well as its 2007 MIS survey. The main assumptions about the current state of treatment seeking behavior, and diagnostic/treatment practices are presented in Table 18. TABLE 18: ASSUMPTIONS ON HEALTH SEEKING BEHAVIOR AND DIAG- NOSTIC/TREATMENT PRACTICES USED TO COST ACTS AND RDTS FOR ELIMINATION Health Seeking Behavior Testing Rates (RDT at $0.58) Treatment (ACT at $1.08) Number of Malaria Cases 2009 (Estimates based on the 2007 MIS Survey) !" 50% public sector !" 26% private sector !" 24% seek no care !" 25% of all OPD patients in public sector !" 2% of patients in private sector !" All positive cases are treated with an ACT in both public an private sector !" 10% of people visiting the private sector are treated presumptively !" Based on extrapolations from the MEEDS data for 2009 2020 and thereafter (Estimates based on assumed changes over time related to ZMCP targets and/or recommendation for Chapter 1) !" 74% public sector !" 26% private sector !" 0% seek no care !" 35% of all OPD (equivalent to 100% of fever cases) !" 20% of all people seeking care in private sector (or all fever cases) !" All positive cases are treated with an ACT in both public an private sector !" 0.5% of people visiting the private sector are treated presumptively !" Based on results from the simulator described in Chapter 1 Using these assumptions, the cost of case management increases four-fold over the course of an elimination program (see Figure 27). The main drivers of this increase are greater volume of RDTs and the cost of quality assurance/control of those tests. Over time, almost all fever or history of fever cases are assumed to seek care from public and private facilities requiring a corresponding significant increases in the number of tests performed. In contrast, with the case load reducing over time, the cost of treatment will be very modest, representing less than 1% of the total cost of case management. Under both elimination scenarios, the number of confirmed malaria cases will constantly reduce over time. However, this is not the main driver of the reduction in the cost for treatment. Rather, this is primarily explained by the cessation of presumptive treatment in the private sector.
US $ FIGURE 27: COST OF RDTS AND QUALITY ASSURANCE/CONTROL FOR ELIMINATION 700,000 600,000 500,000 400,000 300,000 200,000 100,000 0 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 SURVEILLANCE RAPID DIAGNOSTICS TESTS QUALITY CONTROL ON RDT’S A robust surveillance system is one of the most essential components of an elimination program and, as such, the resources that must be devoted to surveillance under elimination will be substantially greater than under sustained control. There are three main differences between the surveillance approach assumed for elimination compared with that of sustained control: �� Inclusion of Private Sector: Since it is essential that all malaria cases be tracked under an elimination program (including those that do not present in public health facilities), an elimination surveillance program in Zanzibar must include all private facilities. We thus assume that the MEEDS system would be expanded to all public facilities under sustained control and all cases, including cases detected in the private sector, trigger an appropriate response. �� Case Investigation: Under an elimination program, all suspected or reported malaria cases must be investigated. This costing includes district case investigation teams that travel to the household of the malaria patient, determine the likely source of the malaria infection, and screen surrounding households. As discussed in the technical feasibility section, we assume 100 households surrounding each newly identified case will be screened. �� Outbreak Response: Successfully achieving elimination will require that malaria outbreaks (>3 secondary cases) that do occur are halted as quickly as possible through focused vector control, screening and treatment. While the costs of the first priority are fixed (i.e., the functioning of the MEEDS system) and therefore should be constant over time, the costs of case investigation and outbreak response will depend on the number of malaria cases. The estimates of the expected number of cases that will require case investigation are based on the simulations described in Chapter 1 and vary based on the two core scenarios costed here. To calculate the number of surveillance teams that would be required to conduct this response, the number of expected cases and corresponding number of households to be screened were extrapolated. These 3 | Financial Feasibility variables were adjusted based on the heterogeneity of transmission on Zanzibar, with the highest transmission risk districts (>2% prevalence) receiving one team additional to the number indicated by the estimated households requiring screening each year. It is assumed that one team of 3 can screen 20 houses per day and would work for 24 days per month. Districts with no transmission risk would not conduct active surveillance. For both costing scenarios, it is assumed that two districts are high risk, six are medium risk, and two are no risk until 2020. After 2020, it is assumed that 1 district shifts from high to medium risk. Salaries of surveillance officers, transport costs (one vehicle per team, including maintenance), and administrative overhead are all included in the costing. The surveillance cost also includes the cost of RDTs used to screen all households. The simulator from the technical feasibility chapter suggests that screening 100 households for each detected case is extremely likely to prevent an outbreak but we still included a contingency budget for outbreak response of initially $100,000 (the cost of a targeted IRS campaign in a single district) and $50,000 once elimination is achieved (outbreaks are even less likely to occur following elimination because of the assumed reductions in importation risk). The technical feasibility chapter describes how the main cost driver for surveillance–the number of cases that will trigger household screenings–depends heavily on assumptions of importation risk. It is expected that reductions in malaria transmission on the mainland alone will not be sufficient to achieve the very low levels of importation risk assumed in scenario 2. As such, targeted screening of travelers entering the islands at the main seaports (Stonetown, Mkoani or Wete, and Mkokotoni) is also assumed and costed for this scenario. TABLE 19: ASSUMPTIONS ON REDUCTIONS OF IMPORTATION RISK FOR 2 ELIMINATION SCENARIOS 2010 2020 2030 Importation risk: Scenario 1 2/1000/year 1/1000/year 1/1000/year Reduction because of malaria control measures on the mainland Importation risk: Scenario 2 2/1000/year 1/1000/year 0.4/1000/year As there is no technical guidance and few experiences in other countries on which to base the assumed approach to border screening, the costing of this added intervention is inherently rough. It is assumed that cost drivers would include ongoing human resources, RDTs, other basic consumables, and management overhead. Assuming that screening would be conducted on board the vessels with an average travel time of 4 hours per trip and that a team can screen up to 30 passengers per hour, it was estimated that 25 teams would be needed to deal with the maximum ferry capacity of around 3,000 passengers a day. It is important to emphasize that this approach is intended to only be used for the purpose of the costing of reduced importation risk and not as a basis for operational decisions; if the MOHSW wishes to explore implementation of border screening in the near-term, the authors recommend that a much more detailed 71
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PHOTO: © SASJA VAN VECHGEL MALARIA
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ACKNOWLEDGEMENTS The feasibility as
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EXECUTIVE SUMMARY Over the past sev
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Financial Feasibility The optimal m
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INTRODUCTION BACKGROUND In October
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FIGURE 2.1: AVERAGE MONTHLY RAINFAL
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CHAPTER 1: TECHNICAL FEASIBILITY IN
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to below 1% with IRS (Bhattarai et
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Page 67: CONCLUSIONS This chapter considers
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Page 83 and 84: REFERENCES Afridi MK (2009). Use of
Page 85 and 86: Jacobs, Lesley A (9/2007). Rights a
Page 87 and 88: Sandberg, Ingstad K, Bjune G (2007)
Page 89: World Health Organization, Global M
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