Publications by authors named "Thomas Rehle"

Background: HIV drug resistance (HIVDR) testing was included in the 2017 South African national HIV household survey. We describe the prevalence of HIVDR by drug class, age, sex and antiretroviral drugs (ARV) status.

Methods: Dried blood were spots tested for HIV, with Viral load (VL), exposure to ARVs and HIVDR testing among those HIV positive.

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Introduction: Oral preexposure prophylaxis (PrEP) in the form of tenofovir-disoproxil-fumarate/emtricitabine is being implemented in selected sites in South Africa. Addressing outstanding questions on PrEP cost-effectiveness can inform further implementation.

Methods: We calibrated an individual-based model to KwaZulu-Natal to predict the impact and cost-effectiveness of PrEP, with use concentrated in periods of condomless sex, accounting for effects on drug resistance.

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Objective: To assess changes and equity in antiretroviral therapy (ART) use in Kenya and South Africa.

Methods: We analysed national population-based household surveys conducted in Kenya and South Africa between 2007 and 2012 for factors associated with lack of ART use among people living with HIV (PLHIV) aged 15-64 years. We considered ART use to be inequitable if significant differences in use were found between groups of PLHIV (e.

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A recent infection testing algorithm (RITA) that includes a test for recent HIV infection and a viral load (VL) test is the recommended strategy to estimate national HIV incidence, reducing false-recent misclassification to <1%. The inclusion of information on exposure to antiretroviral therapy (ART), as a supplement to VL testing, could improve RITA performance by further lowering false-recent misclassification of true long-term infection. In 2012, Kenya and South Africa conducted national population-based surveys that collected information on HIV recency (i.

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Background: South African (SA) national HIV seroprevalence estimates are of crucial policy relevance in the country, and for the worldwide HIV response. However, the most recent nationally representative HIV test survey in 2012 had 22% test non-participation, leaving the potential for substantial bias in current seroprevalence estimates, even after controlling for selection on observed factors.

Objective: To re-estimate national HIV prevalence in SA, controlling for bias due to selection on both observed and unobserved factors in the 2012 SA National HIV Prevalence, Incidence and Behaviour Survey.

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Introduction: Age-disparate sex has long been considered a factor that increases HIV risk for young women in South Africa. However, recent studies from specific regions in South Africa have found conflicting evidence. Few studies have assessed the association between age-disparate partnerships (those involving an age gap of 5 years or more) and HIV risk at the national level.

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This article presents key findings from the 2012 HIV prevalence, incidence and behaviour survey conducted in South Africa and explores trends in the HIV epidemic. A representative household based survey collected behavioural and biomedical data among people of all ages. Chi-squared test for association and formal trend tests (2002, 2005, 2008 and 2012) were used to test for associations and trends in the HIV epidemic across the four surveys.

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Background: South Africa is one of the 22 high tuberculosis burden countries that contribute 80% of the global tuberculosis cases. Tuberculosis is infectious and due to its rapid and easy transmission route poses a threat to population health. Considering the importance of social and psychological factors in influencing health outcomes, appraising knowledge and awareness of tuberculosis, remain vital for effective tuberculosis control.

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South Africa has experienced declining marriage rates and the increasing practice of cohabitation without marriage. This study aims to improve the understanding of the relationship between marital status and HIV in South Africa, an HIV hyperendemic country, through an analysis of findings from the 2012 South African National HIV Prevalence, Incidence and Behaviour Survey. The nationally representative population-based cross-sectional survey collected data on HIV and socio-demographic and behavioural determinants in South Africa.

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Background: Mathematical models are widely used to simulate the effects of interventions to control HIV and to project future epidemiological trends and resource needs. We aimed to validate past model projections against data from a large household survey done in South Africa in 2012.

Methods: We compared ten model projections of HIV prevalence, HIV incidence, and antiretroviral therapy (ART) coverage for South Africa with estimates from national household survey data from 2012.

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Background: The interpretation of HIV prevalence trends is increasingly difficult as antiretroviral treatment programs expand. Reliable HIV incidence estimates are critical to monitoring transmission trends and guiding an effective national response to the epidemic.

Methods And Findings: We used a range of methods to estimate HIV incidence in South Africa: (i) an incidence testing algorithm applying the Limiting-Antigen Avidity Assay (LAg-Avidity EIA) in combination with antiretroviral drug and HIV viral load testing; (ii) a modelling technique based on the synthetic cohort principle; and (iii) two dynamic mathematical models, the EPP/Spectrum model package and the Thembisa model.

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Article Synopsis
  • People with HIV can spread the virus through their sexual activities, and taking medication called ART helps prevent this spread.
  • A study in South Africa showed that people on ART were less likely to have risky sexual behaviors compared to those not on ART, meaning they were better at using condoms.
  • Overall, the study found that people on ART had safer sexual practices than those who were not taking the medication, which is important for stopping HIV from spreading.
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Background: UNAIDS aims for 90% of HIV-positive individuals to be diagnosed by 2020, but few attempts have been made in developing countries to estimate the fraction of the HIV-positive population that has been diagnosed.

Methods: To estimate the rate of HIV diagnosis in South Africa, reported numbers of HIV tests performed in the South African public and private health sectors were aggregated, and estimates of HIV prevalence in individuals tested for HIV were combined. The data were integrated into a mathematical model of the South African HIV epidemic, which was additionally calibrated to estimates of the fraction of the population ever tested for HIV, as reported in three national household surveys.

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Objectives: National population-wide HIV prevalence and incidence trends in sub-Saharan Africa (SSA) are indirectly estimated using HIV prevalence measured among pregnant women attending antenatal clinics (ANC), among other data. We evaluated whether recent HIV prevalence trends among pregnant women are representative of general population trends.

Design: Serial population-based household surveys in 13 SSA countries.

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HIV counselling and testing (HCT) is considered important because it is an entry point to a comprehensive continuum of care for HIV/AIDS. The South African Department of Health launched an HCT campaign in April 2010, and this reached 13,269,746 people by June 2011, of which 16% tested HIV positive and 400,000 of those were initiated into antiretroviral treatment. The overall objective of this project was to gain insight into the general perceptions about HIV testing in the different South African communities.

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This study aims to assess trends in human immunodeficiency virus (HIV) incidence in South Africa, and to assess the extent to which prevention and treatment programmes have reduced HIV incidence. Two models of the South African HIV epidemic, the STI (sexually transmitted infection)-HIV Interaction model and the ASSA2003 AIDS and Demographic model, were adapted. Both models were fitted to age-specific HIV prevalence data from antenatal clinic surveys and household surveys, using a Bayesian approach.

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Background: The prevention of mother-to-child transmission (PMTCT) of HIV has been focused mainly on women who are HIV positive at their first antenatal visit, but there is uncertainty regarding the contribution to overall transmission from mothers who seroconvert after their first antenatal visit and before weaning.

Method: A mathematical model was developed to simulate changes in mother-to-child transmission of HIV over time, in South Africa. The model allows for changes in infant feeding practices as infants age, temporal changes in the provision of antiretroviral prophylaxis and counseling on infant feeding, as well as temporal changes in maternal HIV prevalence and incidence.

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Background: Guidelines for treatment of pediatric HIV have recently changed to recommend that all infants who are identified as HIV-infected should start antiretroviral treatment (ART) immediately, regardless of their immunologic or clinical status. This study aims to assess the likely impact of this change in guideline in South Africa.

Methods: A mathematical model was developed to simulate mother-to-child transmission of HIV, disease progression, and death of HIV-infected children <15 years of age.

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Age at sexual debut is an important determinant of HIV infection. The paper investigates the effects of age at sexual debut on sexual behaviour among South African youth. Among 2 875 respondents who ever had sexual intercourse, 39% had early sexual debut (sexual debut at age 16 years and below).

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Objectives: The scaling up of antiretroviral treatment (ART) for HIV-infected adults requires a sizeable investment of resources in the South African public health care system. It is important that these resources are used productively and in ways that reach those in need, irrespective of social status or personal characteristics. In this study we evaluate whether the distribution of ART services in the public system reflects the distribution of need among adults in the urban population.

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Serological assays for estimating HIV-1 incidence are prone to misclassification, limiting the accuracy of the incidence estimate. Adjustment factors have been developed and recommended for estimating assay-based HIV-1 incidence in cross-sectional settings. We evaluated the performance of the recommended adjustment factors for estimating incidence in national HIV surveys in three countries in sub-Saharan Africa.

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