Browsing by Author "Vassall, Anna"

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    Feasibility, yield, and cost of active tuberculosis case finding linked to a mobile HIV service in Cape Town, South Africa: a cross-sectional study
    (Public Library of Science, 2012) Kranzer, Katharina; Lawn, Stephen D; Meyer-Rath, Gesine; Vassall, Anna; Raditlhalo, Eudoxia; Govindasamy, Darshini; Van Schaik, Nienke; Wood, Robin; Bekker, Linda-Gail
    Katharina Kranzer and colleagues investigate the operational characteristics of an active tuberculosis case-finding service linked to a mobile HIV testing unit that operates in underserviced areas in Cape Town, South Africa.
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    Rapid diagnosis of tuberculosis with the Xpert MTB/RIF assay in high burden countries: a cost-effectiveness analysis
    (Public Library of Science, 2011) Vassall, Anna; van Kampen, Sanne; Sohn, Hojoon; Michael, Joy S; John, K R; den Boon, Saskia; Davis, J Lucian; Whitelaw, Andrew; Nicol, Mark P; Gler, Maria Tarcela; Khaliqov, Anar; Zamudio, Carlos; Perkins, Mark D; Boehme, Catharina C; Cobelens, Frank
    Background: Xpert MTB/RIF (Xpert) is a promising new rapid diagnostic technology for tuberculosis (TB) that has characteristics that suggest large-scale roll-out. However, because the test is expensive, there are concerns among TB program managers and policy makers regarding its affordability for low- and middle-income settings. Methods and Findings: We estimate the impact of the introduction of Xpert on the costs and cost-effectiveness of TB care using decision analytic modelling, comparing the introduction of Xpert to a base case of smear microscopy and clinical diagnosis in India, South Africa, and Uganda. The introduction of Xpert increases TB case finding in all three settings; from 72%–85% to 95%–99% of the cohort of individuals with suspected TB, compared to the base case. Diagnostic costs (including the costs of testing all individuals with suspected TB) also increase: from US$28–US$49 to US$133–US$146 and US$137–US$151 per TB case detected when Xpert is used "in addition to" and "as a replacement of" smear microscopy, respectively. The incremental cost effectiveness ratios (ICERs) for using Xpert "in addition to" smear microscopy, compared to the base case, range from US$41–$110 per disability adjusted life year (DALY) averted. Likewise the ICERS for using Xpert "as a replacement of" smear microscopy range from US$52–$138 per DALY averted. These ICERs are below the World Health Organization (WHO) willingness to pay threshold. Conclusions: Our results suggest that Xpert is a cost-effective method of TB diagnosis, compared to a base case of smear microscopy and clinical diagnosis of smear-negative TB in low- and middle-income settings where, with its ability to substantially increase case finding, it has important potential for improving TB diagnosis and control. The extent of cost-effectiveness gain to TB programmes from deploying Xpert is primarily dependent on current TB diagnostic practices. Further work is required during scale-up to validate these findings.
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    Structure and agency in the economics of public policy for TB control
    (2019) Foster, Nicola; Cleary, Susan; Sinanovic, Edina; Vassall, Anna
    Globally, Tuberculosis remains a devastating disease, despite the availability of treatment. The disease is associated with poverty, and those with the disease incur a high cost of accessing care, while simultaneously experiencing income loss due to a loss in productivity. A key challenge in TB programmes remains the accurate diagnosis of the disease, especially in people who are HIV positive. Diagnosing TB can be very resource intensive and the accuracy of diagnosis is dependent on a range of disease, health service organisation and provider behaviour factors. This thesis seeks to enhance understanding of how the behaviour of healthcare workers mediates the value of TB diagnostic algorithms, and how this may affect the costs, outcomes as well as the economic burden associated with the disease in South Africa. The work presented is based on empirical work done alongside a pragmatic cluster randomized control trial. Empirically, it examines the longitudinal economic burden of TB diagnosis and treatment in South Africa. The discrepancies between the time at which patients incur the greatest cost and income loss, and the available social protection are highlighted. Based on empirical work, a purpose-built state-transition mathematical model of TB diagnosis and treatment was developed to estimate the cost-effectiveness, from the perspective of the health service and the patient, of health systems interventions to strengthen TB diagnosis. Recognising healthcare workers as those who ultimately express policies, the behaviour of healthcare workers was included in the cost-effectiveness analysis by 1) using data from a pragmatic trial reflecting routine practice and clinical decision-making at the time of the study; 2) developing a conceptual framework of the relationship between behaviour at decision points and disease outcomes; and 3) investigating how these interactions may influence the value of the diagnostic algorithm. Possible public policy levers to improve TB diagnosis in healthcare facilities, as well as the potential mediators of costs and effects were explored. The thesis concludes with recommendations for further methodological work to expand on the approach explored in this thesis to improve how heterogeneity in estimates of cost-effectiveness is presented to decision-makers.
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    Tuberculosis infection prevention and control: why we need a whole systems approach
    (2020-05-25) Kielmann, Karina; Karat, Aaron S; Zwama, Gimenne; Colvin, Christopher; Swartz, Alison; Voce, Anna S.; Yates, Tom A; MacGregor, Hayley; McCreesh, Nicky; Kallon, Idriss; Vassall, Anna; Govender, Indira; Seeley, Janet; Grant, Alison D
    Infection prevention and control (IPC) measures to reduce transmission of drug-resistant and drug-sensitive tuberculosis (TB) in health facilities are well described but poorly implemented. The implementation of TB IPC has been assessed primarily through quantitative and structured approaches that treat administrative, environmental, and personal protective measures as discrete entities. We present an on-going project entitled Umoya omuhle (“good air”), conducted in two provinces of South Africa, that adopts an interdisciplinary, ‘whole systems’ approach to problem analysis and intervention development for reducing nosocomial transmission of Mycobacterium tuberculosis (Mtb) through improved IPC. We suggest that TB IPC represents a complex intervention that is delivered within a dynamic context shaped by policy guidelines, health facility space, infrastructure, organisation of care, and management culture. Methods drawn from epidemiology, anthropology, and health policy and systems research enable rich contextual analysis of how nosocomial Mtb transmission occurs, as well as opportunities to address the problem holistically. A ‘whole systems’ approach can identify leverage points within the health facility infrastructure and organisation of care that can inform the design of interventions to reduce the risk of nosocomial Mtb transmission.