Yesim Tozan
Yesim Tozan
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Associate Professor of Global and Environmental Health
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Professional overview
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Dr. Yesim Tozan’s research centers on health decision science and priority setting, and explores the costs and cost-effectiveness of health care interventions using decision analytic models and the issues of health care resource allocation in low- and middle-income countries. Her main focus has been infectious disease prevention and control with an emphasis on dengue and malaria. Dr. Tozan is currently leading a health economics work package in a European Union-funded research project on dengue surveillance and control with field sites in Sri Lanka and Thailand. She is also leading a prospective multi-center study on the cost of dengue illness in international travelers utilizing a network of travel clinics in Europe, the US, the Middle East and Australia. Most recently, she has been working on economic evaluation of artemisinin-based combination therapies for the treatment of uncomplicated childhood malaria using data from multi-site randomized clinical trials in Africa and Asia. Dr. Tozan was a task force associate for the UN Millennium Project’s Task Force on HIV/AIDS, Malaria, Tuberculosis and Access to Essential Medicines and was lead author of the malaria task force report entitled “Coming to grips with malaria in the new millennium.”
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Education
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BS, Environmental Engineering, Istanbul Technical University, TurkeyMS, Environmental Technology, Bogazici University, TurkeyMA, Public Affairs, Princeton University, Princeton, NJPhD, Public Affairs, Princeton University, Princeton, NJ
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Areas of research and study
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Cost EffectivenessCost-effective Health Programs and PoliciesEconomic EvaluationHealth EconomicsInfectious DiseasesPrevention Interventions
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Publications
Publications
Cost-Effectiveness of an Economic Empowerment and Family Intervention for School-going Adolescent Girls in Uganda
AbstractTozan, Y. (n.d.).Publication year
2025Journal title
AJPHAbstract~Costing of a Combination Intervention (Kyaterekera) Addressing Sexual Risk-Taking Behaviors among Vulnerable Women in Southern Uganda
AbstractTozan, Y., Kiyingi, J., Kim, S., Nabayinda, J., Namuwonge, F., Nsubuga, E., Nakabuye, F., Sensoy, O. B., Nabunya, P., Mayo-Wilson, L. J., McKay, M. M., Witte, S. S., & Ssewamala, F. M. (n.d.).Publication year
2024Journal title
American Journal of Tropical Medicine and HygieneVolume
110Issue
5Page(s)
1046-1056AbstractIn Uganda, women engaged in sex work (WESW) are a marginalized population at the intersection of multiple vulnerabilities. The Kyaterekera intervention is targeted at WESW in Rakai and the greater Masaka regions in Uganda and combines a traditional HIV risk-reduction approach with a savings-led economic empowerment intervention and financial literacy training. We estimated the economic costs of the Kyaterekera intervention from a program provider perspective using a prospective activity-based micro-costing method. All program activities and resource uses were measured and valued across the control arm receiving a traditional HIV risk-reduction intervention and the treatment arm receiving a matched individual development savings account and financial literacy training on top of HIV risk reduction. The total per-participant cost by arm was adjusted for inflation and discounted at an annual rate of 3% and presented in 2019 US dollars. The total per-participant costs of the control and intervention arms were estimated at $323 and $1,435, respectively, using the per-protocol sample. When calculated based on the intent-to-treat sample, the per-participant costs were reduced to $183 and $588, respectively. The key cost drivers were the capital invested in individual development accounts and personnel and transportation costs for program operations, linked to WESW's higher mobility and the dispersed pattern of hot spot locations. The findings provide evidence of the economic costs of implementing a targeted intervention for this marginalized population in resource-constrained settings and shed light on the scale of potential investment needed to better achieve the health equity goal of HIV prevention strategies.Costing of a Multiple Family Group Strengthening Intervention (SMART Africa) to Improve Child and Adolescent Behavioral Health in Uganda
AbstractTozan, Y., Capasso, A., Namatovu, P., Kiyingi, J., Damulira, C., Nabayinda, J., Bahar, O. S., McKay, M. M., Hoagwood, K., & Ssewamala, F. M. (n.d.).Publication year
2022Journal title
The American journal of tropical medicine and hygieneVolume
106Issue
4Page(s)
1078-1085AbstractReliable cost estimates are key to assessing the feasibility, affordability, and cost-effectiveness of interventions. We estimated the economic costs of a multiple family group (MFG) intervention-child and adolescent mental health evidence-based practices (CAMH-EBP) implemented under the SMART Africa study, seeking to improve family functioning and reduce child and adolescent behavior problems-delivered through task-shifting by community health workers (CHWs) or parent peers (PPs) in school settings in Uganda. This prospective microcosting analysis was conducted from a provider perspective as part of a three-armed randomized controlled trial of the MFG intervention involving 2,391 participants aged 8-13 years and their caregivers in 26 primary schools. Activity-specific costs were estimated and summed, and divided by actual participant numbers in each study arm to conservatively calculate total per-child costs by arm. Total per-child costs of the MFG-PP and MFG-CHW arms were estimated at US$346 and US$328, respectively. The higher per-child cost of the MFG-PP arm was driven by lower than anticipated attendance by participants recruited to this arm. Personnel costs were the key cost driver, accounting for approximately 70% of total costs because of intensive supervision and support provided to MFG facilitators and intervention quality assurance efforts. This is the first study estimating the economic costs of an evidence-based MFG intervention provided through task-shifting strategies in a low-resource setting. Compared with the costs of other family-based interventions ranging between US$500 and US$900 in similar settings, the MFG intervention had a lower per-participant cost; however, few comparisons are available in the literature. More costing studies on CAMH-EBPs in low-resource settings are needed.Costs of Dengue Control Activities and Hospitalizations in the Public Health Sector during an Epidemic Year in Urban Sri Lanka
AbstractTozan, Y., Thalagala, N., Tissera, H., Palihawadana, P., Amarasinghe, A., Ambagahawita, A., Wilder-Smith, A., Shepard, D. S., & Tozan, Y. (n.d.).Publication year
2016Journal title
PLoS neglected tropical diseasesVolume
10Issue
2AbstractBackground: Reported as a public health problem since the 1960s in Sri Lanka, dengue has become a high priority disease for public health authorities. The Ministry of Health is responsible for controlling dengue and other disease outbreaks and associated health care. The involvement of large numbers of public health staff in dengue control activities year-round and the provision of free medical care to dengue patients at secondary care hospitals place a formidable financial burden on the public health sector. Methods: We estimated the public sector costs of dengue control activities and the direct costs of hospitalizations in Colombo, the most heavily urbanized district in Sri Lanka, during the epidemic year of 2012 from the Ministry of Health’s perspective. The financial costs borne by public health agencies and hospitals are collected using cost extraction tools designed specifically for the study and analysed retrospectively using a combination of activity-based and gross costing approaches. Results: The total cost of dengue control and reported hospitalizations was estimated at US$3.45 million (US$1.50 per capita) in Colombo district in 2012. Personnel costs accounted for the largest shares of the total costs of dengue control activities (79%) and hospitalizations (46%). The results indicated a per capita cost of US$0.42 for dengue control activities. The average costs per hospitalization ranged between US$216–609 for pediatric cases and between US$196–866 for adult cases according to disease severity and treatment setting. Conclusions: This analysis is a first attempt to assess the economic burden of dengue response in the public health sector in Sri Lanka. Country-specific evidence is needed for setting public health priorities and deciding about the deployment of existing or new technologies. Our results suggest that dengue poses a major economic burden on the public health sector in Sri Lanka.Countries' progress towards Global Health Security (GHS) increased health systems resilience during the Coronavirus Disease-19 (COVID-19) pandemic: A difference-in-difference study of 191 countries
AbstractTozan, Y., Headley, T. Y., Kim, S., & Tozan, Y. (n.d.).Publication year
2025Journal title
PLOS global public healthVolume
5Issue
1Page(s)
e0004051AbstractResearch on health systems resilience during the Coronavirus Disease-2019 pandemic frequently used the Global Health Security Index (GHSI), a composite index scoring countries' health security and related capabilities. Conflicting results raised questions regarding the validity of the GHSI as a reliable index. This study attempted to better characterize when and to what extent countries' progress towards Global Health Security (GHS) augments health systems resilience. We used longitudinal data from 191 countries and a difference-in-difference (DiD) causal inference strategy to quantify the effect of countries' GHS capacity as measured by the GHSI on their coverage rates for essential childhood immunizations, a previously established proxy for health systems resilience. Using a sliding scale of cutoff values with step increments of one, we divided countries into treatment and control groups and determined the lowest GHSI score at which a safeguarding effect was observed. All analyses were adjusted for potential confounders. World Bank governance indicators were employed for robustness tests. While countries with overall GHSI scores of 57 and above prevented declines in childhood immunization coverage rates from 2020-2022 (coef: 0.91; 95% CI: 0.41-1.41), this safeguarding effect was strongest in 2021 (coef: 1.23; 95% CI: 0.05-2.41). Coefficient sizes for overall GHSI scores were smaller compared to several GHSI sub-components, including countries' environmental risks (coef: 4.28; 95% CI: 2.56-5.99) and emergency preparedness and response planning (coef: 1.82; 95% CI: 0.54-3.11). Our findings indicate that GHS was positively associated with health systems resilience during the pandemic (2020) and the following two years (2021-2022), that GHS may have had the most significant protective effects in 2021 as compared with 2020 and 2022, and that countries' underlying characteristics, including governance quality, bolstered health systems resilience during the pandemic.Countries’ progress towards Global Health Security (GHS) increased health systems resilience during the Coronavirus Disease-19 (COVID-19) pandemic : A difference-indifference study of 191 countries
AbstractHeadley, T. Y., Kim, S., & Tozan, Y. (n.d.).Publication year
2025Journal title
PLOS Global Public HealthVolume
5Issue
1AbstractResearch on health systems resilience during the Coronavirus Disease-2019 pandemic frequently used the Global Health Security Index (GHSI), a composite index scoring countries’ health security and related capabilities. Conflicting results raised questions regarding the validity of the GHSI as a reliable index. This study attempted to better characterize when and to what extent countries’ progress towards Global Health Security (GHS) augments health systems resilience. We used longitudinal data from 191 countries and a difference-in-difference (DiD) causal inference strategy to quantify the effect of countries’ GHS capacity as measured by the GHSI on their coverage rates for essential childhood immunizations, a previously established proxy for health systems resilience. Using a sliding scale of cutoff values with step increments of one, we divided countries into treatment and control groups and determined the lowest GHSI score at which a safeguarding effect was observed. All analyses were adjusted for potential confounders. World Bank governance indicators were employed for robustness tests. While countries with overall GHSI scores of 57 and above prevented declines in childhood immunization coverage rates from 2020–2022 (coef: 0.91; 95% CI: 0.41–1.41), this safeguarding effect was strongest in 2021 (coef: 1.23; 95% CI: 0.05–2.41). Coefficient sizes for overall GHSI scores were smaller compared to several GHSI sub-components, including countries’ environmental risks (coef: 4.28; 95% CI: 2.56–5.99) and emergency preparedness and response planning (coef: 1.82; 95% CI: 0.54–3.11). Our findings indicate that GHS was positively associated with health systems resilience during the pandemic (2020) and the following two years (2021–2022), that GHS may have had the most significant protective effects in 2021 as compared with 2020 and 2022, and that countries’ underlying characteristics, including governance quality, bolstered health systems resilience during the pandemic.Cultural adaptation of clinic-based pediatric hiv status disclosure intervention with task shifting in Eastern Uganda
AbstractTozan, Y., Kirabira, J., Nakigudde, J., Huang, K.-Y. Y., Ashaba, S., Nambuya, H., Tozan, Y., & Yang, L. H. (n.d.).Publication year
2025Journal title
AIDS research and therapyVolume
22Issue
1Page(s)
48AbstractHIV status disclosure remains a major challenge among children living with perinatally acquired HIV with many taking treatment up to adolescence without knowing their serostatus. This non-disclosure is influenced by factors like fear of the negative consequences of disclosure. Since HIV status disclosure has been found to have good effects including improving treatment adherence and better mental health outcomes, there is a need to design interventions aimed at improving disclosure rates among children living with HIV. This study aims at adapting a clinic-based pediatric HIV status disclosure intervention and tasking shifting from healthcare workers to caregiver peer supporters in Eastern Uganda.Cultural adaptation of clinic-based pediatric hiv status disclosure intervention with task shifting in Eastern Uganda
AbstractKirabira, J., Nakigudde, J., Huang, K.-Y., Ashaba, S., Nambuya, H., Tozan, Y., & Yang, L. (n.d.).Publication year
2025Journal title
AIDS Research and TherapyVolume
22Issue
1AbstractBackground: HIV status disclosure remains a major challenge among children living with perinatally acquired HIV with many taking treatment up to adolescence without knowing their serostatus. This non-disclosure is influenced by factors like fear of the negative consequences of disclosure. Since HIV status disclosure has been found to have good effects including improving treatment adherence and better mental health outcomes, there is a need to design interventions aimed at improving disclosure rates among children living with HIV. This study aims at adapting a clinic-based pediatric HIV status disclosure intervention and tasking shifting from healthcare workers to caregiver peer supporters in Eastern Uganda. Methods: The adaptation process involved consultations with caregivers, healthcare workers involved in the care of children living with HIV, researchers in this field, intervention developers, and other experts and stakeholders. This was done through conducting FGDs with HCWs, caregivers, and peer supporters and consultations with researchers in the field of HIV. The original intervention manual was translated to Lusoga which is the commonly spoken dialect in this region. Collected qualitative data were analyzed using an inductive approach to develop themes and subthemes. Written informed consent will be obtained from all participants before participation in the study. Results: A total of 28 participants were involved in the FGDs, while two pediatricians and two HIV researchers/specialists were consulted. Six themes were generated in relation to all suggested changes to the original manual which were related to: (1) sociocultural beliefs/norms/perceptions (5 FGDs), (2) boosting caregiver’s confidence for disclosure (5FGDs), (3) disclosure mode, environment, and person (4 FGDs), (4) health facility/system related changes (3 FGDs), (5) reorganization/paraphrasing (3FGDs) and (6) age appropriateness (2FGDs). Conclusion: This study emphasized that whereas some aspects of intervention can apply to various contexts, there is a need for cross-cultural adaptation of interventions before being implemented in settings where they were not developed.Current issues in the economics of vaccination against dengue
AbstractTozan, Y. (n.d.).Publication year
2016Journal title
Expert Review of VaccinesVolume
15Issue
4Page(s)
519-528AbstractDengue is a major public health concern in tropical and subtropical areas of the world. The prospects for dengue prevention have recently improved with the results of efficacy trials of a tetravalent dengue vaccine. Although partially effective, once licensed, its introduction can be a public health priority in heavily affected countries because of the perceived public health importance of dengue. This review explores the most immediate economic considerations of introducing a new dengue vaccine and evaluates the published economic analyses of dengue vaccination. Findings indicate that the current economic evidence base is of limited utility to support country-level decisions on dengue vaccine introduction. There are a handful of published cost-effectiveness studies and no country-specific costing studies to project the full resource requirements of dengue vaccine introduction. Country-level analytical expertise in economic analyses, another gap identified, needs to be strengthened to facilitate evidence-based decision-making on dengue vaccine introduction in endemic countries.Dengue Research Funded by the European Commission-Scientific Strategies of Three European Dengue Research Consortia
AbstractJaenisch, T., Sakuntabhai, A., Wilder-smith, A., Halstead, S. B., & Tozan, Y. (n.d.).Publication year
2013Journal title
PLoS Neglected Tropical DiseasesVolume
7Issue
12Page(s)
e2320Abstract~Dengue tools : Innovative tools and strategies for the surveillance and control of dengue
AbstractWilder-Smith, A., Renhorn, K. E., Tissera, H., Bakar, S. A., Alphey, L., Kittayapong, P., Lindsay, S., Logan, J., Hatz, C., Reiter, P., Rocklöv, J., Byass, P., Louis, V. R., Tozan, Y., Massad, E., Tenorio, A., Lagneau, C., L'Ambert, G., Brooks, D. I., … Gubler, D. (n.d.).Publication year
2012Journal title
Global Health ActionVolume
5Issue
1AbstractDengue fever is a mosquito-borne viral disease estimated to cause about 230 million infections worldwide every year, of which 25,000 are fatal. Global incidence has risen rapidly in recent decades with some 3.6 billion people, over half of the world's population, now at risk, mainly in urban centres of the tropics and subtropics. Demographic and societal changes, in particular urbanization, globalization, and increased international travel, are major contributors to the rise in incidence and geographic expansion of dengue infections. Major research gaps continue to hamper the control of dengue. The European Commission launched a call under the 7th Framework Programme with the title of 'Comprehensive control of Dengue fever under changing climatic conditions'. Fourteen partners from several countries in Europe, Asia, and South America formed a consortium named 'DengueTools' to respond to the call to achieve better diagnosis, surveillance, prevention, and predictive models and improve our understanding of the spread of dengue to previously uninfected regions (including Europe) in the context of globalization and climate change.The consortium comprises 12 work packages to address a set of research questions in three areas:Research area 1: Develop a comprehensive early warning and surveillance system that has predictive capability for epidemic dengue and benefits from novel tools for laboratory diagnosis and vector monitoring.Research area 2: Develop novel strategies to prevent dengue in children.Research area 3: Understand and predict the risk of global spread of dengue, in particular the risk of introduction and establishment in Europe, within the context of parameters of vectorial capacity, global mobility, and climate change.In this paper, we report on the rationale and specific study objectives of 'DengueTools'. DengueTools is funded under the Health theme of the Seventh Framework Programme of the European Community, Grant Agreement Number: 282589 Dengue Tools.Dichlorodiphenyltrichloroethane (DDT) for indoor residual spraying in Africa : How can it be used for malaria control?
AbstractTozan, Y., Sadasivaiah, S., Tozan, Y., & Breman, J. G. (n.d.).Publication year
2007Journal title
American Journal of Tropical Medicine and HygieneVolume
77Issue
SUPPL. 6Page(s)
249-263AbstractIn 2006, the World Health Organization issued a position statement promoting the use of indoor residual spraying (IRS) with dichlorodiphenyltrichloroethane (DDT) for malaria vector control in epidemic and endemic areas. Other international organizations concurred because of the great burden of malaria and the relative ineffectiveness of current treatment and control strategies. Although the Stockholm Convention of 2001 targeted DDT as 1 of 12 persistent organic pollutants for phase-out and eventual elimination, it allowed a provision for its continued indoor use for disease vector control. Although DDT is a low-cost antimalarial tool, the possible adverse human health and environmental effects of exposure through IRS must be carefully weighed against the benefits to malaria control. This article discusses the controversy surrounding the use of DDT for IRS; its effective implementation in Africa; recommendations for deployment today, and training, monitoring, and research needs for effective and sustainable implementation. We consider the costs and cost effectiveness of IRS with DDT, alternative insecticides to DDT, and the importance of integrated vector control if toxicity, resistance, and other issues restrict its use.Dihydroartemisinin-piperaquine vs. artemether-lumefantrine for first-line treatment of uncomplicated malaria in African children : A cost-effectiveness analysis
AbstractTozan, Y., Pfeil, J., Borrmann, S., & Tozan, Y. (n.d.).Publication year
2014Journal title
PloS oneVolume
9Issue
4AbstractBackground: Recent multi-centre trials showed that dihydroartemisinin- piperaquine (DP) was as efficacious and safe as artemether-lumefantrine (AL) for treatment of young children with uncomplicated P. falciparum malaria across diverse transmission settings in Africa. Longitudinal follow-up of patients in these trials supported previous findings that DP had a longer post-treatment prophylactic effect than AL, reducing the risk of reinfection and conferring additional health benefits to patients, particularly in areas with moderate to high malaria transmission. Methods: We developed a Markov model to assess the cost-effectiveness of DP versus AL for first-line treatment of uncomplicated malaria in young children from the provider perspective, taking into consideration the post-treatment prophylactic effects of the drugs as reported by a recent multi-centre trial in Africa and using the maximum manufacturer drug prices for artemisinin-based combination therapies set by the Global Fund in 2013. We estimated the price per course of treatment threshold above which DP would cease to be a cost-saving alternative to AL as a first-line antimalarial drug. Results: First-line treatment with DP compared to AL averted 0.03 DALYs (95% CI: 0.006-0.07) and 0.001 deaths (95% CI: 0.00-0.002) and saved $0.96 (95% CI: 0.33-2.46) per child over one year. The results of the threshold analysis showed that DP remained cost-saving over AL for any DP cost below $1.23 per course of treatment. Conclusions: DP is superior to AL from both the clinical and economic perspectives for treatment of uncomplicated P. falciparum malaria in young children. A paediatric dispersible formulation of DP is under development and should facilitate a targeted deployment of this antimalarial drug. The use of DP as first-line antimalarial drug in paediatric malaria patients in moderate to high transmission areas of Africa merits serious consideration by health policymakers.Economic Abuse and Care-seeking Practices for HIV and Financial Support Services in Women Employed by Sex Work : A Cross-Sectional Baseline Assessment of a Clinical Trial Cohort in Uganda
AbstractJennings Mayo-Wilson, L., Yen, B. J., Nabunya, P., Bahar, O. S., Wright, B. N., Kiyingi, J., Filippone, P. L., Mwebembezi, A., Kagaayi, J., Tozan, Y., Nabayinda, J., Witte, S. S., & Ssewamala, F. M. (n.d.).Publication year
2022Journal title
Journal of Interpersonal ViolenceAbstractEconomic hardship is a driver of entry into sex work, which is associated with high HIV risk. Yet, little is known about economic abuse in women employed by sex work (WESW) and its relationship to uptake of HIV prevention and financial support services. This study used cross-sectional baseline data from a multisite, longitudinal clinical trial that tests the efficacy of adding economic empowerment to traditional HIV risk reduction education on HIV incidence in 542 WESW. Mixed effects logistic and linear regressions were used to examine associations in reported economic abuse by demographic characteristics, sexual behaviors, HIV care-seeking, and financial care-seeking. Mean age was 31.4 years. Most WESW were unmarried (74%) and had less than primary school education (64%). 48% had savings, and 72% had debt. 93% reported at least one economic abuse incident. Common incidents included being forced to ask for money (80%), having financial information kept from them (61%), and being forced to disclose how money was spent (56%). WESW also reported partners/relatives spending money needed for bills (45%), not paying bills (38%), threatening them to quit their job(s) (38%), and using physical violence when earning income (24%). Married/partnered WESW (OR = 2.68, 95% CI:1.60–4.48), those with debt (OR = 1.70, 95% CI:1.04–2.77), and those with sex-work bosses (OR = 1.90, 95% CI:1.07–3.38) had higher economic abuse. Condomless sex (β = +4.43, pEconomic burden of caregiving for persons with severe mental illness in sub-Saharan Africa : A systematic review
AbstractAddo, R., Agyemang, S. A., Tozan, Y., & Nonvignon, J. (n.d.).Publication year
2018Journal title
PloS oneVolume
13Issue
8AbstractBackground Over the past two decades, the focus of mental health care has shifted from institutionalisation to community-based programs and short hospital stays. This change means that there is an increased role for caregivers, mostly family members, in managing persons with mental illness. Although there is evidence to support the benefits of deinstitutionalisation of mental health care, there are also indications of substantial burden experienced by caregivers; the evidence of which is limited in sub-Saharan Africa. However, knowledge of the nature and extent of this burden can inform the planning of mental health services that will not only benefit patients, but also caregivers and households. Objective To systematically review the available evidence on the economic burden of severe mental illness on primary family caregivers in sub-Saharan Africa. Methods A comprehensive search was conducted in Pubmed, CINAHL, Econlit and Web of Science with no date limitations up to September 2016 using keywords such as "burden", "cost of illness" and "economic burden" to identify relevant published literature. Articles were appraised using a standardised data extraction tool covering themes such as physical, psychological and socioeconomic burden. Results Seven papers were included in the review. Caregivers were mostly family members with a mean age of 46.34, female and unemployed. Five out of seven studies (71%) estimated the full economic burden of severe mental illness on caregivers. The remainder of studies just described the caregiver burden. All seven papers reported moderate to severe caregiver burden characterised by financial constraint, productivity loss and lost employment. The caregiver’s level of income and employment status, severity of patient’s condition and duration of mental illness were reported to negatively affect the economic burden experienced by caregivers. Conclusion There is paucity of studies reporting the burden of severe mental illness on caregivers in sub-Saharan Africa. Further research is needed to present the nature and extent of this burden to inform service planning and policymaking.Economic cost and quality of life of family caregivers of schizophrenic patients attending psychiatric hospitals in Ghana
AbstractOpoku-Boateng, Y. N., Kretchy, I. A., Aryeetey, G. C., Dwomoh, D., Decker, S., Agyemang, S. A., Tozan, Y., Aikins, M., & Nonvignon, J. (n.d.).Publication year
2017Journal title
BMC health services researchVolume
17AbstractBackground: Low and middle income countries face many challenges in meeting their populations' mental health care needs. Though family caregiving is crucial to the management of severe mental health disabilities, such as schizophrenia, the economic costs borne by family caregivers often go unnoticed. In this study, we estimated the household economic costs of schizophrenia and quality of life of family caregivers in Ghana. Methods: We used a cost of illness analysis approach. Quality of life (QoL) was assessed using the abridged WHO Quality of Life (WHOQOL-BREF) tool. Cross-sectional data were collected from 442 caregivers of patients diagnosed with schizophrenia at least six months prior to the study and who received consultation in any of the three psychiatric hospitals in Ghana. Economic costs were categorized as direct costs (including medical and non-medical costs of seeking care), indirect costs (productivity losses to caregivers) and intangible costs (non-monetary costs such as stigma and pain). Direct costs included costs of medical supplies, consultations, and travel. Indirect costs were estimated as value of productive time lost (in hours) to primary caregivers. Intangible costs were assessed using the Zarit Burden Interview (ZBI). We employed multiple regression models to assess the covariates of costs, caregiver burden, and QoL. Results: Total monthly cost to caregivers was US$ 273.28, on average. Key drivers of direct costs were medications (50%) and transportation (27%). Direct costs per caregiver represented 31% of the reported monthly earnings. Mean caregiver burden (measured by the ZBI) was 16.95 on a scale of 0-48, with 49% of caregivers reporting high burden. Mean QoL of caregivers was 28.2 (range: 19.6-34.8) out of 100. Better educated caregivers reported lower indirect costs and better QoL. Caregivers with higher severity of depression, anxiety and stress reported higher caregiver burden and lower QoL. Males reported better QoL. Conclusions: These findings highlight the high household burden of caregiving for people living with schizophrenia in low income settings. Results underscore the need for policies and programs to support caregivers.Effect of El Niño–Southern Oscillation and local weather on Aedes dvector activity from 2010 to 2018 in Kalutara district, Sri Lanka : a two-stage hierarchical analysis
AbstractLiyanage, P., Tozan, Y., Overgaard, H. J., Aravinda Tissera, H., & Rocklöv, J. (n.d.).Publication year
2022Journal title
The Lancet Planetary HealthVolume
6Issue
7Page(s)
e577-e585AbstractBackground: Dengue, transmitted by Aedes mosquitoes, is a major public health problem in Sri Lanka. Weather affects the abundance, feeding patterns, and longevity of Aedes vectors and hence the risk of dengue transmission. We aimed to quantify the effect of weather variability on dengue vector indices in ten Medical Officer of Health (MOH) divisions in Kalutara, Sri Lanka. Methods: Monthly weather variables (rainfall, temperature, and Oceanic Niño Index [ONI]) and Aedes larval indices in each division in Kalutara were obtained from 2010 to 2018. Using a distributed lag non-linear model and a two-stage hierarchical analysis, we estimated and compared division-level and overall relationships between weather and premise index, Breteau index, and container index. Findings: From Jan 1, 2010, to Dec 31, 2018, three El Niño events (2010, 2015–16, and 2018) occurred. Increasing monthly cumulative rainfall higher than 200 mm at a lag of 0 months, mean temperatures higher than 31·5°C at a lag of 1–2 months, and El Niño conditions (ie, ONI >0·5) at a lag of 6 months were associated with an increased relative risk of premise index and Breteau index. Container index was found to be less sensitive to temperature and ONI, and rainfall. The associations of rainfall and temperature were rather homogeneous across divisions. Interpretation: Both temperature and ONI have the potential to serve as predictors of vector activity at a lead time of 1–6 months, while the amount of rainfall could indicate the magnitude of vector prevalence in the same month. This information, along with knowledge of the distribution of breeding sites, is useful for spatial risk prediction and implementation of effective Aedes control interventions. Funding: None.Effectiveness and Cost-Effectiveness study of the Affordable Medicines Facility-malaria: Feasibility Report
AbstractTozan, Y., Thiede, M., Müller, O., & Panea, R. (n.d.).Publication year
2011Abstract~Efficacy and cost-effectiveness of environmental management for malaria control
AbstractUtzinger, J., Tozan, Y., & Singer, B. H. (n.d.).Publication year
2001Journal title
Tropical Medicine and International HealthVolume
6Issue
9Page(s)
677-687AbstractRoll back malaria (RBM) aims at halving the current burden of the disease by the year 2010. The focus is on sub-Saharan Africa, and it is proposed to implement efficacious and cost-effective control strategies. But the evidence base of such information is scarce, and a notable missing element is the discussion of the potential of environmental management. We reviewed the literature and identified multiple malaria control programmes that incorporated environmental management as the central feature. Prominent among them are programmes launched in 1929 and implemented for two decades at copper mining communities in Zambia. The full package of control measures consisted of vegetation clearance, modification of river boundaries, draining swamps, oil application to open water bodies and house screening. Part of the population also was given quinine and was sleeping under mosquito nets. Monthly malaria incidence rates and vector densities were used for surveillance and adaptive tuning of the environmental management strategies to achieve a high level of performance. Within 3-5 years, malaria-related mortality, morbidity and incidence rates were reduced by 70-95%. Over the entire 20 years of implementation, the programme had averted an estimated 4173 deaths and 161 205 malaria attacks. The estimated costs per death and malaria attack averted were US$ 858 and US$ 22.20, respectively. Over the initial 3-5 years start-up period, analogous to the short-duration of cost-effectiveness analyses of current studies, we estimated that the costs per disability adjusted life year (DALY) averted were US$ 524-591. However, the strategy has a track record of becoming cost-effective in the longer term, as maintenance costs were much lower: US$ 22-92 per DALY averted. In view of fewer adverse ecological effects, increased sustainability and better uses of local resources and knowledge, environmental management - integrated with pharmacological, insecticidal and bednet interventions - could substantially increase the chances of rolling back malaria.Emerging consensus in HIV/AIDS, malaria, tuberculosis, and access to essential medicines
AbstractRuxin, J., Paluzzi, J. E., Wilson, P. A., Tozan, Y., Kruk, M., & Teklehaimanot, A. (n.d.).Publication year
2005Journal title
LancetVolume
365Issue
9459Page(s)
618-621Abstract~Employment conditions as barriers to the adoption of COVID-19 mitigation measures : how the COVID-19 pandemic may be deepening health disparities among low-income earners and essential workers in the United States
AbstractCapasso, A., Kim, S., Ali, S. H., Jones, A. M., DiClemente, R. J., & Tozan, Y. (n.d.).Publication year
2022Journal title
BMC public healthVolume
22Issue
1AbstractBackground: The COVID-19 pandemic has disproportionately impacted economically-disadvantaged populations in the United States (US). Precarious employment conditions may contribute to these disparities by impeding workers in such conditions from adopting COVID-19 mitigation measures to reduce infection risk. This study investigated the relationship between employment and economic conditions and the adoption of COVID-19 protective behaviors among US workers during the initial phase of the COVID-19 pandemic. Methods: Employing a social media advertisement campaign, an online, self-administered survey was used to collect data from 2,845 working adults in April 2020. Hierarchical generalized linear models were performed to assess the differences in engagement with recommended protective behaviors based on employment and economic conditions, while controlling for knowledge and perceived threat of COVID-19, as would be predicted by the Health Belief Model (HBM). Results: Essential workers had more precarious employment and economic conditions than non-essential workers: 67% had variable income; 30% did not have paid sick leave; 42% had lost income due to COVID-19, and 15% were food insecure. The adoption of protective behaviors was high in the sample: 77% of participants avoided leaving home, and 93% increased hand hygiene. Consistent with the HBM, COVID-19 knowledge scores and perceived threat were positively associated with engaging in all protective behaviors. However, after controlling for these, essential workers were 60% and 70% less likely than non-essential workers, who by the nature of their jobs cannot stay at home, to stay at home and increase hand hygiene, respectively. Similarly, participants who could not afford to quarantine were 50% less likely to avoid leaving home (AOR: 0.5; 95% CI: 0.4, 0.6) than those who could, whereas there were no significant differences concerning hand hygiene. Conclusions: Our findings are consistent with the accumulating evidence that the employment conditions of essential workers and other low-income earners are precarious, that they have experienced disproportionately higher rates of income loss during the initial phase of the COVID-19 pandemic and face significant barriers to adopting protective measures. Our findings underscore the importance and need of policy responses focusing on expanding social protection and benefits to prevent the further deepening of existing health disparities in the US.Erratum : Author Correction: Using remote sensing environmental data to forecast malaria incidence at a rural district hospital in Western Kenya (Scientific reports (2017) 7 1 (2589))
AbstractSewe, M. O., Tozan, Y., Ahlm, C., & Rocklöv, J. (n.d.).Publication year
2018Journal title
Scientific reportsVolume
8Issue
1Page(s)
5032AbstractA correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.Erratum to Correction : Dengue Research Funded by the European Commission-Scientific Strategies of Three European Dengue Research Consortia (The PLOS Neglected Tropical Diseases Staff)
AbstractTozan, Y. (n.d.).Publication year
2014Journal title
PLoS neglected tropical diseasesVolume
8Issue
4Abstract~European projections of West Nile virus transmission under climate change scenarios
AbstractTozan, Y., Farooq, Z., Sjödin, H., Semenza, J. C., Tozan, Y., Sewe, M. O. O., Wallin, J., & Rocklöv, J. (n.d.).Publication year
2023Journal title
One health (Amsterdam, Netherlands)Volume
16Page(s)
100509AbstractWest Nile virus (WNV), a mosquito-borne zoonosis, has emerged as a disease of public health concern in Europe. Recent outbreaks have been attributed to suitable climatic conditions for its vectors favoring transmission. However, to date, projections of the risk for WNV expansion under climate change scenarios is lacking. Here, we estimate the WNV-outbreaks risk for a set of climate change and socioeconomic scenarios. We delineate the potential risk-areas and estimate the growth in the population at risk (PAR). We used supervised machine learning classifier, XGBoost, to estimate the WNV-outbreak risk using an ensemble climate model and multi-scenario approach. The model was trained by collating climatic, socioeconomic, and reported WNV-infections data (2010-22) and the out-of-sample results (1950-2009, 2023-99) were validated using a novel Confidence-Based Performance Estimation (CBPE) method. Projections of area specific outbreak risk trends, and corresponding population at risk were estimated and compared across scenarios. Our results show up to 5-fold increase in West Nile virus (WNV) risk for 2040-60 in Europe, depending on geographical region and climate scenario, compared to 2000-20. The proportion of disease-reported European land areas could increase from 15% to 23-30%, putting 161 to 244 million people at risk. Across scenarios, Western Europe appears to be facing the largest increase in the outbreak risk of WNV. The increase in the risk is not linear but undergoes periods of sharp changes governed by climatic thresholds associated with ideal conditions for WNV vectors. The increased risk will require a targeted public health response to manage the expansion of WNV with climate change in Europe.European projections of West Nile virus transmission under climate change scenarios
AbstractFarooq, Z., Sjödin, H., Semenza, J. C., Tozan, Y., Sewe, M. O., Wallin, J., & Rocklöv, J. (n.d.).Publication year
2023Journal title
One HealthVolume
16AbstractWest Nile virus (WNV), a mosquito-borne zoonosis, has emerged as a disease of public health concern in Europe. Recent outbreaks have been attributed to suitable climatic conditions for its vectors favoring transmission. However, to date, projections of the risk for WNV expansion under climate change scenarios is lacking. Here, we estimate the WNV-outbreaks risk for a set of climate change and socioeconomic scenarios. We delineate the potential risk-areas and estimate the growth in the population at risk (PAR). We used supervised machine learning classifier, XGBoost, to estimate the WNV-outbreak risk using an ensemble climate model and multi-scenario approach. The model was trained by collating climatic, socioeconomic, and reported WNV-infections data (2010−22) and the out-of-sample results (1950–2009, 2023–99) were validated using a novel Confidence-Based Performance Estimation (CBPE) method. Projections of area specific outbreak risk trends, and corresponding population at risk were estimated and compared across scenarios. Our results show up to 5-fold increase in West Nile virus (WNV) risk for 2040-60 in Europe, depending on geographical region and climate scenario, compared to 2000-20. The proportion of disease-reported European land areas could increase from 15% to 23-30%, putting 161 to 244 million people at risk. Across scenarios, Western Europe appears to be facing the largest increase in the outbreak risk of WNV. The increase in the risk is not linear but undergoes periods of sharp changes governed by climatic thresholds associated with ideal conditions for WNV vectors. The increased risk will require a targeted public health response to manage the expansion of WNV with climate change in Europe.