Browsing by Author "Hargrove, John"

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    The effect of diagnostic delays on the drop-out rate and the total delay to diagnosis of tuberculosis
    (Public Library of Science, 2008-04-09) Millen, Stephen J.; Uys, Pieter W.; Hargrove, John; Van Helden, Paul D.; Williams, Brian G.
    Background: Numerous patient and healthcare system-related delays contribute to the overall delay experienced by patients from onset of TB symptoms to diagnosis and treatment. Such delays are critical as infected individuals remain untreated in the community, providing more opportunities for transmission of the disease and adversely affecting the epidemic. Methodology/Principal Findings: We present an analysis of the factors that contribute to the overall delay in TB diagnosis and treatment, in a resource-poor setting. Impact on the distribution of diagnostic delay times was assessed for various factors, the sensitivity of the diagnostic method being found to be the most significant. A linear relationship was found between the sensitivity of the test and the predicted mean delay time, with an increase in test sensitivity resulting in a reduced mean delay time and a reduction in the drop-out rate. Conclusions/Significance: The results show that in a developing country a number of delay factors, particularly the low sensitivity of the initial sputum smear microscopy test, potentially increase total diagnostic delay times experienced by TB patients significantly. The results reinforce the urgent need for novel diagnostic methods, both for smear positive and negative TB, that are highly sensitive, accessible and point of care, in order to reduce mean delay times. © 2008 Millen et al.
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    Estimating HIV incidence among adults in Kenya and Uganda : a systematic comparison of multiple methods
    (Public Library of Science, 2011-03-07) Kim, Andrea A.; Hallett, Timothy; Stover, John; Gouws, Eleanor; Musinguzi, Joshua; Mureithi, Patrick K.; Bunnell, Rebecca; Hargrove, John; Mermin, Jonathan; Kaiser, Reinhard K.; Barsigo, Anne; Ghys, Peter D.
    Background: Several approaches have been used for measuring HIV incidence in large areas, yet each presents specific challenges in incidence estimation. Methodology/Principal Findings: We present a comparison of incidence estimates for Kenya and Uganda using multiple methods: 1) Epidemic Projections Package (EPP) and Spectrum models fitted to HIV prevalence from antenatal clinics (ANC) and national population-based surveys (NPS) in Kenya (2003, 2007) and Uganda (2004/2005); 2) a survey-derived model to infer age-specific incidence between two sequential NPS; 3) an assay-derived measurement in NPS using the BED IgG capture enzyme immunoassay, adjusted for misclassification using a locally derived false-recent rate (FRR) for the assay; (4) community cohorts in Uganda; (5) prevalence trends in young ANC attendees. EPP/Spectrum-derived and survey-derived modeled estimates were similar: 0.67 [uncertainty range: 0.60, 0.74] and 0.6 [confidence interval: (CI) 0.4, 0.9], respectively, for Uganda (2005) and 0.72 [uncertainty range: 0.70, 0.74] and 0.7 [CI 0.3, 1.1], respectively, for Kenya (2007). Using a local FRR, assay-derived incidence estimates were 0.3 [CI 0.0, 0.9] for Uganda (2004/2005) and 0.6 [CI 0, 1.3] for Kenya (2007). Incidence trends were similar for all methods for both Uganda and Kenya. Conclusions/Significance: Triangulation of methods is recommended to determine best-supported estimates of incidence to guide programs. Assay-derived incidence estimates are sensitive to the level of the assay's FRR, and uncertainty around high FRRs can significantly impact the validity of the estimate. Systematic evaluations of new and existing incidence assays are needed to the study the level, distribution, and determinants of the FRR to guide whether incidence assays can produce reliable estimates of national HIV incidence.
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    Migration, mines and mores : the HIV epidemic in southern Africa
    (Academy of Science of South Africa, 2008) Hargrove, John
    The seriousness of the HIV epidemic in southern and eastern Africa has its roots in the 19th century - in the employment practices instituted on mines, farms and in cities, where millions of men have, ever since, lived apart from their families for the greater part of each year. This destruction of the family unit was a sociological disaster waiting for the arrival of HIV and is the source of many other social ills - not least the increasingly violent nature of South African society. In the short term we can promote HIV prevention measures such as male circumcision and condom use. In the medium term, we can hope that the many billions already spent on microbicide and vaccine research begin to pay dividends. In the long term, we need to change fundamentally the way that people live.
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    Migration, mines and mores : the HIV epidemic in Southern Africa
    (Stellenbosch : University of Stellenbosch, 2007) Hargrove, John; Van der Merwe, Mattie; University of Stellenbosch
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    The potential impact of male circumcision on HIV in Sub-Saharan Africa
    (Public Library of Science -- PLoS, 2006-07) Williams, Brian G.; Lloyd-Smith, James O.; Gouws, Eleanor; Hankins, Catherine; Getz, Wayne M.; Hargrove, John; De Zoysa, Isabelle; Dye, Christopher; Auvert, Bertran
    Background A randomized controlled trial (RCT) has shown that male circumcision (MC) reduces sexual transmission of HIV from women to men by 60% (32% 76%; 95% CI) offering an intervention of proven efficacy for reducing the sexual spread of HIV. We explore the implications of this finding for the promotion of MC as a public health intervention to control HIV in sub-Saharan Africa. Methods and Findings Using dynamical simulation models we consider the impact of MC on the relative prevalence of HIV in men and women and in circumcised and uncircumcised men. Using country level data on HIV prevalence and MC, we estimate the impact of increasing MC coverage on HIV incidence, HIV prevalence, and HIV-related deaths over the next ten, twenty, and thirty years in sub-Saharan Africa. Assuming that full coverage of MC is achieved over the next ten years, we consider three scenarios in which the reduction in transmission is given by the best estimate and the upper and lower 95% confidence limits of the reduction in transmission observed in the RCT. MC could avert 2.0 (1.1 3.8) million new HIV infections and 0.3 (0.1 0.5) million deaths over the next ten years in sub-Saharan Africa. In the ten years after that, it could avert a further 3.7 (1.9 7.5) million new HIV infections and 2.7 (1.5 5.3) million deaths, with about one quarter of all the incident cases prevented and the deaths averted occurring in South Africa. We show that a) MC will increase the proportion of infected people who are women from about 52% to 58%; b) where there is homogenous mixing but not all men are circumcised, the prevalence of infection in circumcised men is likely to be about 80% of that in uncircumcised men; c) MC is equivalent to an intervention, such as a vaccine or increased condom use, that reduces transmission in both directions by 37%. Conclusions This analysis is based on the result of just one RCT, but if the results of that trial are confirmed we suggest that MC could substantially reduce the burden of HIV in Africa, especially in southern Africa where the prevalence of MC is low and the prevalence of HIV is high. While the protective benefit to HIV-negative men will be immediate, the full impact of MC on HIV-related illness and death will only be apparent in ten to twenty years.