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1.  Mother-to-child transmission of HIV in a community-based antiretroviral clinic in South Africa 
To examine the uptake of ART among pregnant women referred to an ART service and the associated rates and risk factors for vertical HIV transmission.
Retrospective analysis of an observational cohort at a community ART clinic in Cape Town.
Between 2002 and 2008, 367 treatment-naïve pregnant women accessed the clinic. The median age was 27.5 years, and median gestation at presentation was 28 weeks. The median baseline CD4 count and viral load were 134 cells/µl and 28 282 copies/ml. Two hundred and sixty-five women (72%) commenced ART before giving birth, 73 women (20%) were referred for prevention of mother-to-child transmission therapy (PMTCT), and 29 (8%) received no intervention. Among ART-eligible women, 13% were lost to follow-up. Of those starting ART, median duration of therapy prior to birth was 7.6 weeks (interquartile range (IQR) 4 – 11.9). The HIV transmission rate was 5.1% (95% confidence interval (CI) 2.8 – 9.0%). Factors associated with transmission were advanced maternal WHO disease stage (odds ratio (OR) 9.57, p=0.02), and follow-up viral load above 50 copies/ml (OR 3.64, p=0.03). Each additional week on ART reduced transmission by 20% (p=0.05). There was no HIV transmission among women who received more than 8 weeks’ therapy.
The rate of HIV transmission in this study was higher than reported in high-income countries. Prevention of vertical transmission with ART was hindered by women presenting late in pregnancy and with advanced stage of HIV disease. Interventions that facilitate earlier ART commencement and improve programmatic retention of pregnant women are required.
PMCID: PMC3954611  PMID: 21414276
2.  Decreasing household contribution to TB transmission with age: a retrospective geographic analysis of young people in a South African township 
BMC Infectious Diseases  2014;14:221.
Tuberculosis (TB) transmission rates are exceptionally high in endemic TB settings. Adolescence represents a period of increasing TB infection and disease but little is known as to where adolescents acquire TB infection. We explored the relationship between residential exposure to adult TB cases and infection in children and adolescents in a South African community with high burdens of TB and HIV.
TB infection data were obtained from community, school-based tuberculin skin test (TST) surveys performed in 2006, 2007 and 2009. A subset of 2007 participants received a repeat TST in 2009, among which incident TB infections were identified. Using residential address, all adult TB cases notified by the community clinic between 1996 and 2009 were cross-referenced with childhood and adolescent TST results. Demographic and clinic data including HIV status were abstracted for TB cases. Multivariate logistic regression models examined the association of adult TB exposure with childhood and adolescent prevalent and incident TB infection.
Of 1,100 children and adolescents included in the prevalent TB infection analysis, 480 (44%) were TST positive and 651 (59%) were exposed to an adult TB case on their residential plot. Prevalent TB infection in children aged 5–9 and 10–14 years was positively associated with residential exposure to an adult TB case (odds ratio [OR]:2.0; 95% confidence interval [CI]: 1.1-3.6 and OR:1.5; 95% CI: 1.0-2.3 respectively), but no association was found in adolescents ≥15 years (OR:1.4; 95% CI: 0.9-2.0). HIV status of adult TB cases was not associated with TB infection (p = 0.62). Of 67 previously TST negative children, 16 (24%) converted to a positive TST in 2009. These incident infections were not associated with residential exposure to an adult TB case (OR: 1.9; 95% CI: 0.5-7.3).
TB infection among young children was strongly associated with residential exposure to an adult TB case, but prevalent and incident TB infection in adolescents was not associated with residential exposure. The HIV-status of adult TB cases was not a risk factor for transmission. The high rates of TB infection and disease among adolescents underscore the importance of identifying where infection occurs in this age group.
PMCID: PMC4012060  PMID: 24758715
Tuberculosis; Infection; Transmission; Adolescents
3.  The HVTN503/Phambili HIV vaccine trial: a comparison of younger and older participants 
By comparing younger to older participants enrolled in a HIV vaccine efficacy trial, we aimed to gain insights into the inclusion of adolescents in future trials. This was a sub-analysis of a multisite HIV vaccine randomized clinical trial in South Africa, conducted January-September, 2007. Motivations for trial enrollment, social harms, adverse events, and loss to follow-up were compared between younger (18-20 years old) and older participants (21-35 years old). Both younger (n=238) and older participants (n=563) were equally likely to report enrolling for altruistic reasons. Younger females were less likely than older participants to join for trial reimbursement (p=0.005), while younger males were more likely to enroll because the vaccine may provide protection from HIV-acquisition (p<0.001). There were no significant differences in the number of social harms reported. Compared to males over 20 years-old, 18-20-year-old females were less likely to experience adverse events (OR=0.1, CI 0.01-0.80) and no more likely to be lost to follow up (OR=0.7, CI 0.39-1.25), while 18-20-year-old males were no more likely to experience adverse events (OR=1.3, CI 0.58-2.83) or loss to follow-up (OR=0.8, CI 0.51-1.41). Our data support the inclusion of younger participants who are at risk for HIV in future HIV vaccine efficacy trials.
PMCID: PMC3968181  PMID: 24104693
HIV; vaccine trials; clinical trials; youth; South Africa
4.  Undiagnosed Tuberculosis in a Community with High HIV Prevalence 
Background: Although failure of tuberculosis (TB) control in sub-Saharan Africa is attributed to the HIV epidemic, it is unclear why the directly observed therapy short-course (DOTS) strategy is insufficient in this setting. We conducted a cross-sectional survey of pulmonary TB (PTB) and HIV infection in a community of 13,000 with high HIV prevalence and high TB notification rate and a well-functioning DOTS TB control program.
Methods: Active case finding for PTB was performed in 762 adults using sputum microscopy and Mycobacterium tuberculosis culture, testing for HIV, and a symptom and risk factor questionnaire. Survey findings were correlated with notification data extracted from the TB treatment register.
Results: Of those surveyed, 174 (23%) tested HIV positive, 11 (7 HIV positive) were receiving TB therapy, 6 (5 HIV positive) had previously undiagnosed smear-positive PTB, and 6 (4 HIV positive) had smear-negative/culture-positive PTB. Symptoms were not a useful screen for PTB. Among HIV-positive and -negative individuals, prevalence of notified smear-positive PTB was 1,563/100,000 and 352/100,000, undiagnosed smear-positive PTB prevalence was 2,837/100,000 and 175/100,000, and case-finding proportions were 37 and 67%, respectively. Estimated duration of infectiousness was similar for HIV-positive and HIV-negative individuals. However, 87% of total person-years of undiagnosed smear-positive TB in the community were among HIV-infected individuals.
Conclusions: PTB was identified in 9% of HIV-infected individuals, with 5% being previously undiagnosed. Lack of symptoms suggestive of PTB may contribute to low case-finding rates. DOTS strategy based on passive case finding should be supplemented by active case finding targeting HIV-infected individuals.
PMCID: PMC1899262  PMID: 16973982
African community; case finding; HIV infection; incidence and prevalence; pulmonary tuberculosis
5.  Mobile phone text messaging for promoting adherence to anti-tuberculosis treatment: a systematic review protocol 
Systematic Reviews  2013;2:6.
In 2010, there were approximately 8.8 million incident cases of tuberculosis (TB) worldwide. The treatment of TB is at least six months long and may be complicated by a high pill burden. In addition, TB patients often do not take their medication on schedule simply because they forget. Mobile phone text messaging has the potential to help promote TB treatment adherence. We, therefore, propose to conduct a review of current best evidence for the use of mobile phone text messaging to promote patient adherence to TB treatment.
This is a systematic review of the literature. We will preferably include randomized controlled trials (RCTs). However, non-randomized studies (NRS) will be considered if there is an inadequate number of RCTs.
We will search PubMed, EMBASE, CINAHL, CENTRAL, Science Citation Index, Africa-Wide Information, and WHOLIS electronic databases for eligible studies available by 30 November 2012 regardless of language or publication status. We will also check reference lists for additional studies, identify abstracts from conference proceedings and communicate with authors for any relevant material.
At least two authors will independently screen search outputs, select studies, extract data and assess the risk of bias (using separate criteria for RCTs and NRS); resolving discrepancies by discussion and consensus. We will assess clinical heterogeneity by examining the types of participants, interventions and outcomes in each study and pool studies judged to be clinically homogenous. We will also assess statistical heterogeneity using the chi-square test of homogeneity and quantify it using the I-square statistic. If study results are found to be statistically homogeneous (that is heterogeneity P > 0.1), we will pool them using the fixed-effect meta-analysis. Otherwise, we will use random-effects meta-analysis. We will calculate risk ratios and their corresponding 95% confidence intervals for dichotomous outcomes, and mean differences for continuous outcomes. For other outcomes without quantitative data, a descriptive analysis will be used.
Our results can be used by researchers and policy-makers to help inform them of the efficacy of mobile phone text messaging interventions to promote patient adherence to TB treatment.
PMCID: PMC3564775  PMID: 23324135
Mobile phone; Text messages; Tuberculosis treatment; Anti-tubercular agents; Adherence; Compliance
6.  Systemic delays in the initiation of antiretroviral therapy during pregnancy do not improve outcomes of HIV-positive mothers: a cohort study 
Antiretroviral therapy (ART) initiation in eligible HIV-infected pregnant women is an important intervention to promote maternal and child health. Increasing the duration of ART received before delivery plays a major role in preventing vertical HIV transmission, but pregnant women across Africa experience significant delays in starting ART, partly due the perceived need to deliver ART counseling and patient education before ART initiation. We examined whether delaying ART to provide pre-ART counseling was associated with improved outcomes among HIV-infected women in Cape Town, South Africa.
We undertook a retrospective cohort study of 490 HIV-infected pregnant women referred to initiate treatment at an urban ART clinic. At this clinic all patients including pregnant women are screened by a clinician and then undergo three sessions of counseling and patient education prior to starting treatment, commonly introducing delays of 2–4 weeks before ART initiation. Data on viral suppression and retention in care after ART initiation were taken from routine clinic records.
A total of 382 women initiated ART before delivery (78%); ART initiation before delivery was associated with earlier gestational age at presentation to the ART service (p < 0.001). The median delay between screening and ART initiation was 21 days (IQR, 14–29 days). Overall, 84.7%, 79.6% and 75.0% of women who were pregnant at the time of ART initiation were retained in care at 4, 8 and 12 months after ART initiation, respectively. Among those retained, 91% were virally suppressed at each follow-up visit. However the delay from screening to ART initiation was not associated with retention in care and/or viral suppression throughout the first year on ART in unadjusted or adjusted analyses.
A substantial proportion of eligible pregnant women referred for ART do not begin treatment before delivery in this setting. Among women who do initiate ART, delaying initiation for patient preparation is not associated with improved maternal outcomes. Given the need to maximize the duration of ART before delivery for prevention of mother-to-child HIV transmission, there is an urgent need for new strategies to help expedite ART initiation in eligible pregnant women.
PMCID: PMC3490939  PMID: 22963318
Antiretroviral therapy; Pregnancy; Patient preparation; Prevention of mother-to-child transmission (PMTCT); HIV/AIDS; South Africa
7.  Lipoarabinomannan in urine during tuberculosis treatment: association with host and pathogen factors and mycobacteriuria 
Detection of lipoarabinomannan (LAM), a Mycobacterium tuberculosis (Mtb) cell wall antigen, is a potentially attractive diagnostic. However, the LAM-ELISA assay has demonstrated variable sensitivity in diagnosing TB in diverse clinical populations. We therefore explored pathogen and host factors potentially impacting LAM detection.
LAM-ELISA assay testing, sputum smear and culture status, HIV status, CD4 cell count, proteinuria and TB outcomes were prospectively determined in adults diagnosed with TB and commencing TB treatment at a South African township TB clinic. Sputum TB isolates were characterised by IS61110-based restriction fragment length polymorphism (RFLP) and urines were tested for mycobacteriuria by Xpert® MTB/RIF assay.
32/199 (16.1%) of patients tested LAM-ELISA positive. Median optical density and proportion testing LAM positive remained unchanged during 2 weeks of treatment and then declined over 24 weeks. LAM was associated with positive sputum smear and culture status, HIV infection and low CD4 cell counts but not proteinuria, RFLP strain or TB treatment outcome. The sensitivity of LAM for TB in HIV-infected patients with CD4 counts of ≥ 200, 100-199, 50-99, and < 50 cells/μl, was 15.2%, 32%, 42.9%, and 69.2% respectively. Mycobacteriuria was found in 15/32 (46.9%) of LAM positive patients and in none of the LAM negative controls.
Urinary LAM was related to host immune factors, was unrelated to Mtb strain and declined steadily after an initial 2 weeks of TB treatment. The strong association of urine LAM with mycobacteriuria is a new finding, indicating frequent TB involvement of the renal tract in advanced HIV infection.
PMCID: PMC3349560  PMID: 22369353
8.  Treatment outcomes in HIV-infected adolescents attending a community-based antiretroviral therapy clinic in South Africa 
Very few data are available on treatment outcomes of adolescents living with HIV infection (whether perinatally acquired or sexually acquired) in sub-Saharan Africa. The present study therefore compared the treatment outcomes in adolescents with those of young adults at a public sector community-based ART programme in Cape Town, South Africa.
Treatment outcomes of adolescents (9-19 years) were compared with those of young adults (20-28 years), enrolled in a prospective cohort between September 2002 and June 2009. Kaplan-Meier estimates and Cox proportional hazard models were used to assess outcomes and determine associations with age, while adjusting for potential confounders. The treatment outcomes were mortality, loss to follow-up (LTFU), immunological response, virological suppression and virological failure.
883 patients, including 65 adolescents (47 perinatally infected and 17 sexually infected) and 818 young adults, received ART. There was no difference in median baseline CD4 cell count between adolescents and young adults (133.5 vs 116 cells/μL; p = 0.31). Overall mortality rates in adolescents and young adults were 1.2 (0.3-4.8) and 3.1 (2.4-3.9) deaths per 100 person-years, respectively. Adolescents had lower rates of virological suppression (< 400 copies/mL) at 48 weeks (27.3% vs 63.1%; p < 0.001). Despite this, however, the median change in CD4 count from baseline at 48 weeks of ART was significantly greater for adolescents than young adults (373 vs 187 cells/μL; p = 0.0001). Treatment failure rates were 8.2 (4.6-14.4) and 5.0 (4.1-6.1) per 100 person-years in the two groups. In multivariate analyses, there was no significant difference in LTFU and mortality between age groups but increased risk in virological failure [AHR 2.06 (95% CI 1.11-3.81; p = 0.002)] in adolescents.
Despite lower virological suppression rates and higher rates of virological failure, immunological responses were nevertheless greater in adolescents than young adults whereas rates of mortality and LTFU were similar. Further studies to determine the reasons for poorer virological outcomes are needed.
PMCID: PMC3295677  PMID: 22273267
antiretroviral; adolescents; outcomes; mortality; virological failure; Africa
9.  Burden of New and Recurrent Tuberculosis in a Major South African City Stratified by Age and HIV-Status 
PLoS ONE  2011;6(10):e25098.
To describe the burden of tuberculosis (TB) in Cape Town by calculating TB incidence rates stratified by age and HIV-status, assessing the contribution of retreatment disease and estimating the cumulative lifetime TB risk in HIV-negative individuals.
Details of TB cases were abstracted from the 2009 electronic TB register. Population denominators were estimated from census data and actuarial estimates of HIV prevalence, allowing calculation of age-specific and HIV-stratified TB notification rates.
The 2009 mid-year population was 3,443,010 (3,241,508 HIV-negative and 201,502 HIV-positive individuals). There were 29,478 newly notified TB cases of which 56% were laboratory confirmed. HIV status was recorded for 87% of cases and of those with known HIV-status 49% were HIV-negative and 51% were positive. Discrete peaks in the incidence of non-HIV-associated TB occurred at three ages: 511/100,000 at 0–4 years of age, 553/100,000 at 20–24 years and 628/100,000 at 45–49 years with 1.5%, 19% and 45% being due to retreatment TB, respectively. Only 15.5% of recurrent cases had a history of TB treatment failure or default. The cumulative lifetime risks in the HIV-negative population of all new TB episodes and new smear-positive TB episodes were 24% and 12%, respectively; the lifetime risk of retreatment disease was 9%. The HIV-positive notification rate was 6,567/100,000 (HIV-associated TB rate ratio = 17). Although retreatment cases comprised 30% of the HIV-associated TB burden, 88% of these patients had no history of prior treatment failure or default.
The annual burden of TB in this city is huge. TB in the HIV-negative population contributed almost half of the overall disease burden and cumulative lifetime risks were similar to those reported in the pre-chemotherapy era. Retreatment TB contributed significantly to both HIV-associated and non-HIV-associated TB but infrequently followed prior inadequate treatment. This likely reflects ongoing TB transmission to both HIV-negative and positive individuals.
PMCID: PMC3189963  PMID: 22016763
10.  HIV Risk and Associations of HIV Infection among men who have sex with men in Peri-Urban Cape Town, South Africa 
BMC Public Health  2011;11:766.
The HIV epidemic in Sub Saharan Africa has been traditionally assumed to be driven by high risk heterosexual and vertical transmission. However, there is an increasing body of data highlighting the disproportionate burden of HIV infection among MSM in the generalized HIV epidemics across of Southern Africa. In South Africa specifically, there has been an increase in attention focused on the risk status and preventive needs of MSM both in urban centers and peri-urban townships. The study presented here represents the first evaluation of HIV prevalence and associations of HIV infection among MSM in the peri-urban townships of Cape Town.
The study consisted of an anonymous probe of 200 men, reporting ever having had sex with another man, recruited through venue-base sampling from January to February, 2009.
Overall, HIV prevalence was 25.5% (n = 51/200). Of these prevalent HIV infections, only 6% of HIV-1 infected MSM were aware of their HIV status (3/50). 0% of men reported always having safe sex as defined by always wearing condoms during sex and using water-based lubricants. Independent associations with HIV infection included inconsistent condom use with male partners (aOR 2.3, 95% CI 1.0-5.4), having been blackmailed (aOR 4.4, 95% CI 1.6-20.2), age over 26 years (aOR 4.2, 95% CI 1.6-10.6), being unemployed (aOR 3.7, 95% CI 1.5-9.3), and rural origin (aOR 6.0, 95% CI 2.2-16.7). Bisexual activity was reported by 17.1% (34/199), and a total of 8% (16/200) reported having a regular female partner. Human rights violations were common with 10.5% (n = 21/200) reporting having been blackmailed and 21.0% (n = 42/200) reporting being afraid to seek health care.
The conclusions from this study include that a there is a high risk and underserved population of MSM in the townships surrounding Cape Town. The high HIV prevalence and high risk sexual practices suggest that prevalence will continue to increase among these men in the context of an otherwise slowing epidemic. These data further highlight the need to better characterize risk factors for HIV prevention and appropriate targeted combination packages of HIV interventions including biomedical, behavioural, and structural approaches to mitigate HIV risk among these men.
PMCID: PMC3196714  PMID: 21975248
11.  Force of tuberculosis infection among adolescents in a high HIV and TB prevalence community: a cross-sectional observation study 
BMC Infectious Diseases  2011;11:156.
Understanding of the transmission dynamics of tuberculosis (TB) in high TB and HIV prevalent settings is required in order to develop effective intervention strategies for TB control. However, there are little data assessing incidence of TB infection in adolescents in these settings.
We performed a tuberculin skin test (TST) and HIV survey among secondary school learners in a high HIV and TB prevalence community. TST responses to purified protein derivative RT23 were read after 3 days. HIV-infection was assessed using Orasure® collection device and ELISA testing. The results of the HIV-uninfected participants were combined with those from previous surveys among primary school learners in the same community, and force of TB infection was calculated by age.
The age of 820 secondary school participants ranged from 13 to 22 years. 159 participants had participated in the primary school surveys. At a 10 mm cut-off, prevalence of TB infection among HIV-uninfected and first time participants, was 54% (n = 334/620). HIV prevalence was 5% (n = 40/816). HIV infection was not significantly associated with TST positivity (p = 0.07). In the combined survey dataset, TB prevalence was 45% (n = 645/1451), and was associated with increasing age and male gender. Force of infection increased with age, from 3% to 7.3% in adolescents ≥20 years of age.
We show a high force of infection among adolescents, positively associated with increasing age. We postulate this is due to increased social contact with infectious TB cases. Control of the TB epidemic in this setting will require reducing the force of infection.
PMCID: PMC3130671  PMID: 21631918
12.  Overcoming Biological, Behavioral and Structural Vulnerabilities: New Directions in Research to Decrease HIV Transmission in Men who have Sex with Men 
Men who have sex with men, including transgender women, comprise a heterogeneous group of individuals, whose sexual behaviors and gender identities may varying widely between cultures and among individuals. Their sources of increased vulnerability to HIV are diverse, including the increased efficiency of HIV transmission via unprotected anal intercourse, sexual role versatility, asymptomatic sexually transmitted infections, as well as behavioral factors that may be associated with condomless sex with multiple partners. Societal stigmatization of homosexual behavior and gender non-conformity may result in internalized negative feelings that lead to depression, other affective disorders, and substance use, which in turn are associated with increased risk taking behaviors. Social stigma and punitive civil environments may lead to delays in seeking HIV and STD screening, and later initiation of antiretroviral therapy. The iPrEX study demonstrated that chemoprophylaxis can decrease HIV acquisition in MSM, and the HPTN 052 study established the biological plausibility that earlier initiation of HAART can decrease HIV transmission to uninfected partners. Despite these advances, MSM remain among the most significantly HIV-affected population in resource rich and limited settings. New studies will integrate enhanced understanding of the biology of enhanced rectal transmission of HIV and the focused use of antiretrovirals for prevention with culturally-tailored approaches that address the potentiating social and behavioral factors associated with enhanced HIV spread among MSM.
PMCID: PMC3740716  PMID: 23764630
Men who have sex with men; Transgender Women; HIV Prevention; HIV Transmission
13.  Preventing HIV among Young People: research priorities for the future 
To review the current state of knowledge on the prevention of sexual transmission of HIV in adolescents and to highlight existing gaps and priority areas for future research.
A disproportionate burden of HIV infections falls on adolescents, a developmental stage marked by unique neural, biological, and social transition. Successful interventions are critical to prevent the spread of HIV in this vulnerable population.
We summarized the current state of research on HIV prevention in adolescents by providing examples of successful interventions and best practices, and highlighting current research gaps.
Adolescent interventions fall into three main categories: biomedical, behavioral, and structural. The majority of current research has focused on individual behavior change, while promising biomedical and structural interventions have been largely understudied in adolescents. Combination prevention interventions may be particularly valuable to this group.
Adolescents have unique needs with respect to HIV prevention and, thus, interventions should be designed to most effectively reach this population with information and services that will be relevant to them.
PMCID: PMC3746811  PMID: 23764629
Adolescence; HIV; Prevention
14.  Gender inequality and HIV transmission: a global analysis 
The HIV pandemic disproportionately impacts young women. Worldwide, young women aged 15–24 are infected with HIV at rates twice that of young men, and young women alone account for nearly a quarter of all new HIV infections. The incommensurate HIV incidence in young – often poor – women underscores how social and economic inequalities shape the HIV epidemic. Confluent social forces, including political and gender violence, poverty, racism, and sexism impede equal access to therapies and effective care, but most of all constrain the agency of women.
HIV prevalence data was compiled from the 2010 UNAIDS Global Report. Gender inequality was assessed using the 2011 United Nations Human Development Report Gender Inequality Index (GII). Logistic regression models were created with predominant mode of transmission (heterosexual vs. MSM/IDU) as the dependent variable and GII, Muslim vs. non-Muslim, Democracy Index, male circumcision rate, log gross national income (GNI) per capita at purchasing power parity (PPP), and region as independent variables.
Results and discussion
There is a significant correlation between having a predominantly heterosexual epidemic and high gender inequality across all models. There is not a significant association between whether a country is predominantly Muslim, has a high/low GNI at PPP, has a high/low circumcision rate, and its primary mode of transmission. In addition, there are only three countries that have had a generalized epidemic in the past but no longer have one: Cambodia, Honduras, and Eritrea. GII data are available only for Cambodia and Honduras, and these countries showed a 37 and 34% improvement, respectively, in their Gender Inequality Indices between 1995 and 2011. During the same period, both countries reduced their HIV prevalence below the 1% threshold of a generalized epidemic. This represents limited but compelling evidence that improvements in gender inequality can lead to the abatement of generalized epidemics.
Gender inequality is an important factor in the maintenance – and possibly in the establishment of – generalized HIV epidemics. We should view improvements in gender inequality as part of a broader public health strategy.
PMCID: PMC4074603  PMID: 24976436
gender inequality; HIV; AIDS; structural interventions; political ecology
15.  Caseation of Human Tuberculosis Granulomas Correlates with Elevated Host Lipid Metabolism 
EMBO molecular medicine  2010;2(7):258-274.
The progression of human tuberculosis to active disease and transmission involves the development of a caseous granuloma that cavitates and releases infectious Mycobacterium tuberculosis bacilli. In the current study, we exploited genome-wide microarray analysis to determine that genes for lipid sequestration and metabolism were highly expressed in caseous tuberculosis granulomas. Immunohistological analysis of these granulomas confirmed the disproportionate abundance of the proteins involved in lipid metabolism in cells surrounding the caseum; namely, adipophilin, acyl-CoA synthetase long-chain family member 1, and saposin C. Biochemical analysis of the lipid species within the caseum identified cholesterol, cholesteryl esters, triacylglycerols, and lactosylceramide, which implicated low-density lipoprotein-derived lipids as the most likely source. M. tuberculosis infection in vitro induced lipid droplet formation in murine and human macrophages. Furthermore, the M. tuberculosis cell wall lipid, trehalose dimycolate, induced a strong granulomatous response in mice, which was accompanied by foam cell formation. These results provide molecular and biochemical evidence that the development of the human tuberculosis granuloma to caseation correlates with pathogen-mediated dysregulation of host lipid metabolism.
PMCID: PMC2913288  PMID: 20597103
16.  Identification of losses to follow-up in a community-based antiretroviral therapy clinic in South Africa using a computerized pharmacy tracking system 
BMC Infectious Diseases  2010;10:329.
High rates of loss to follow-up (LTFU) are undermining rapidly expanding antiretroviral treatment (ART) services in sub-Saharan Africa. The intelligent dispensing of ART (iDART) is an open-source electronic pharmacy system that provides an efficient means of generating lists of patients who have failed to pick-up medication. We determined the duration of pharmacy delay that optimally identified true LTFU.
We conducted a retrospective cross-sectional study of a community-based ART cohort in Cape Town, South Africa. We used iDART to identify groups of patients known to be still enrolled in the cohort on the 1st of April 2008 that had failed to pick-up medication for periods of ≥ 6, ≥ 12, ≥ 18 and ≥ 24 weeks. We defined true LTFU as confirmed failure to pick up medication for 3 months since last attendance. We then assessed short-term and long-term outcomes using a prospectively maintained database and patient records.
On the date of the survey, 2548 patients were registered as receiving ART but of these 85 patients (3.3%) were found to be true LTFU. The numbers of individuals (proportion of the cohort) identified by iDART as having failed to collect medication for periods of ≥6, ≥12, ≥18 and ≥24 weeks were 560 (22%), 194 (8%), 117 (5%) and 80 (3%), respectively. The sensitivities of these pharmacy delays for detecting true LTFU were 100%, 100%, 62.4% and 47.1%, respectively. The corresponding specificities were 80.7%, 95.6%, 97.4% and 98.4%. Thus, the optimal delay was ≥12 weeks since last attendance at this clinic (equivalent to 8 weeks since medication ran out). Pharmacy delays were also found to be significantly associated with LTFU and death one year later.
The iDART electronic pharmacy system can be used to detect patients potentially LTFU and who require recall. Using a short a cut-off period was too non-specific for LTFU and would require the tracing of very large numbers of patients. Conversely prolonged delays were too insensitive. Of the periods assessed, a ≥12 weeks delay appeared optimal. This system requires prospective evaluation to further refine its utility.
PMCID: PMC3000400  PMID: 21078148
17.  Resistance in Pediatric Patients Experiencing Virologic Failure with First- and Second-Line Antiretroviral Therapy 
The Pediatric infectious disease journal  2013;32(6):10.1097/INF.0b013e3182829092.
We examined HIV-1 resistance in children failing first-and second-line antiretroviral therapy (ART) in South Africa, all with clade C virus. Those exposed to full-dose ritonavir had multiple protease resistance mutations. Nineteen percent had wild type virus. Appropriate ART sequencing in sub-Saharan African children is essential for prolong treatment options.
PMCID: PMC3881960  PMID: 23303240
pediatric; antiretroviral therapy; genotype; resource-limited setting; virologic failure; resistance
18.  Utility of interferon-γ ELISPOT assay responses in highly tuberculosis-exposed patients with advanced HIV infection in South Africa 
Interferon-gamma (IFN-γ) ELISPOT assays incorporating Mycobacterium tuberculosis-specific antigens are useful in the diagnosis of tuberculosis (TB) or latent infection. However, their utility in patients with advanced HIV is unknown. We studied determinants of ELISPOT responses among patients with advanced HIV infection (but without active TB) living in a South African community with very high TB notification rates.
IFN-γ responses to ESAT-6 and CFP-10 in overnight ELISPOT assays and in 7-day whole blood assays (WBA) were compared in HIV-infected patients (HIV+, n = 40) and healthy HIV-negative controls (HIV-, n = 30) without active TB. Tuberculin skin tests (TSTs) were also done.
ELISPOTs, WBAs and TSTs were each positive in >70% of HIV- controls, reflecting very high community exposure to M. tuberculosis. Among HIV+ patients, quantitative WBA responses and TSTs (but not the proportion of positive ELISPOT responses) were significantly impaired in those with CD4 cell counts <100 cells/μl compared to those with higher counts. In contrast, ELISPOT responses (but not WBA or TST) were strongly related to history of TB treatment; a much lower proportion of HIV+ patients who had recently completed treatment for TB (n = 19) had positive responses compared to those who had not been treated (11% versus 62%, respectively; P < 0.001). Multivariate analysis confirmed that ELISPOT responses had a strong inverse association with a history of recent TB treatment (adjusted OR = 0.06, 95%CI = 0.10–0.40, P < 0.01) and that they were independent of CD4 cell count and viral load. Among HIV+ individuals who had not received TB treatment both the magnitude and proportion of positive ELISPOT responses (but not TST or WBA) were similar to those of HIV-negative controls.
The proportion of positive ELISPOT responses in patients with advanced HIV infection was independent of CD4 cell count but had a strong inverse association with history of TB treatment. This concurs with the previously documented low TB risk among patients in this cohort with a history of recent treatment for TB. These data suggest ELISPOT assays may be useful for patient assessment and as an immuno-epidemiological research tool among patients with advanced HIV and warrant larger scale prospective evaluation.
PMCID: PMC2031899  PMID: 17725839
19.  Shared Air: A Renewed Focus on Ventilation for the Prevention of Tuberculosis Transmission 
PLoS ONE  2014;9(5):e96334.
Despite an improvement in the overall TB cure rate from 40–74% between 1995 and 2011, TB incidence in South Africa continues to increase. The epidemic is notably disquieting in schools because the vulnerable population is compelled to be present. Older learners (age 15–19) are at particular risk given a smear-positive rate of 427 per 100,000 per year and the significant amount of time they spend indoors. High schools are therefore important locations for potential TB infection and thus prevention efforts.
Methods and Findings
Using portable carbon dioxide monitors, we measured CO2 in classrooms under non-steady state conditions. The threshold for tuberculosis transmission was estimated using a carbon dioxide-based risk equation. We determined a critical rebreathed fraction of carbon dioxide () of 1·6%, which correlates with an indoor CO2 concentration of 1000 ppm. These values correspond with a ventilation rate of 8·6 l/s per person or 12 air exchanges per hour (ACH) for standard classrooms of 180 m3.
Given the high smear positive rate of high-school adolescents in South Africa, the proposal to achieve CO2 levels of 1000ppm through natural ventilation (in the amount 12 ACH) will not only help achieve WHO guidelines for providing children with healthy indoor environments, it will also provide a low-cost intervention for helping control the TB epidemic in areas of high prevalence.
PMCID: PMC4012987  PMID: 24804707
20.  CD4 cell count recovery among HIV-infected patients with very advanced immunodeficiency commencing antiretroviral treatment in sub-Saharan Africa 
Patients accessing antiretroviral treatment (ART) programmes in sub-Saharan Africa frequently have very advanced immunodeficiency. Previous data suggest that such patients may have diminished capacity for CD4 cell count recovery.
Rates of CD4 cell increase were determined over 48 weeks among ART-naïve individuals (n = 596) commencing ART in a South African community-based ART programme.
The CD4 cell count increased from a median of 97 cells/μl at baseline to 261 cells/μl at 48 weeks and the proportion of patients with a CD4 cell count <100 cells/μl decreased from 51% at baseline to just 4% at 48 weeks. A rapid first phase of recovery (0–16 weeks, median rate = 25.5 cells/μl/month) was followed by a slower second phase (16–48 weeks, median rate = 7.7 cells/μl/month). Compared to patients with higher baseline counts, multivariate analysis showed that those with baseline CD4 counts <50 cells/μl had similar rates of phase 1 CD4 cell recovery (P = 0.42), greater rates of phase 2 recovery (P = 0.007) and a lower risk of immunological non-response (P = 0.016). Among those that achieved a CD4 cell count >500 cells/μl at 48 weeks, 19% had baseline CD4 cell counts <50 cells/μl. However, the proportion of these patients that attained a CD4 count 200 cells/μl at 48 weeks was lower than those with higher baseline CD4 cell counts.
Patients in this cohort with baseline CD4 cell counts <50 cells/μl have equivalent or greater capacity for immunological recovery during 48 weeks of ART compared to those with higher baseline CD4 cell counts. However, their CD4 counts remain <200 cells/μl for a longer period, potentially increasing their risk of morbidity and mortality in the first year of ART.
PMCID: PMC1435908  PMID: 16551345
21.  Impact of HIV and CD4 count on tuberculosis diagnosis: analysis of citywide data from Cape Town, South Africa 
The impact of HIV-infection and CD4 count on diagnosis of tuberculosis (TB) at a population level is incompletely defined.
To determine how HIV-infection and CD4 count affect disease site, sputum smear status and overall rate of laboratory confirmation (sputum smear microscopy or culture) of TB cases under routine programme conditions.
Retrospective analysis of the 2009 electronic TB register for Cape Town, South Africa.
Of 29,478 TB cases notified in 2009, HIV-status was known in 25,744 (87.3%) of cases of which 13,237 (51.4%) were HIV-positive. Of these, 61.2% had CD4 cell counts <200 cells/μL, 82.7% had counts <350 cells/μL. Laboratory confirmation of TB (by smear or culture) was obtained less frequently in HIV-infected than HIV-uninfected adult cases (53.9% versus 74.3%; P<0.001). HIV-infection was associated with higher proportions of sputum smear-negative and extrapulmonary TB and lower grades of sputum smear-positivity even among those with CD4 counts ≥ 500 cells/μL. However, the relationship between the proportion of cases testing smear-positive and CD4 count was non-linear.
Much TB lacks laboratory confirmation in this setting despite good laboratory services. HIV-associated TB is more difficult to diagnose even at high CD4 cell counts >500 cells/μL, suggesting an early impact after HIV-sero-conversion.
PMCID: PMC3990260  PMID: 23827024
tuberculosis; HIV; diagnosis; smear microscopy; culture; acid-fast bacilli
22.  Antiretroviral treatment (ART) uptake in patients with HIV-associated tuberculosis (TB) attending co-located TB and ART services 
Delivery of integrated care for patients with HIV-associated tuberculosis (TB) is challenging. We assessed the uptake and timing of antiretroviral treatment (ART) among eligible patients attending a primary care service with co-located ART and TB clinics.
In a retrospective cohort study, all HIV-associated TB patients (≥18 years) who commenced TB treatment in 2010 were included. Data were analysed using basic descriptive statistics and log-binomial regression analysis.
Of a total of 497 patients diagnosed with HIV-associated TB, 274 were eligible to start ART for the first time (median CD4 count, 159 cells/μL). ART was started during TB treatment by 220 (80.3%) patients. Among the 54 (19.7%) who did not start ART, 23 (42.6%) were either lost to follow-up or died before enrolling for ART; 12 (22.2%) were either LTFU or died after enrolling but before starting ART; 5 (9.3%) were transferred-out and 14 (25.9%) only started ART after completion of TB treatment. The median delay between starting TB treatment and starting ART was 51 days (IQR, 29-77). Overall, only 58.6% of patients started ART within 8 weeks of TB treatment and just 12.7% of those with CD4 counts <50 cells/μL started ART within 2 weeks.
In a setting with co-located TB and ART clinics, delays to starting ART were substantial and one fifth of eligible patients did not start ART during TB treatment. Co-location of services alone is insufficient to permit timely initiation of ART and further measures need to be implemented to facilitate integrated treatment.
PMCID: PMC3960570  PMID: 23498041
23.  Mobile HIV Screening in Cape Town, South Africa: Clinical Impact, Cost and Cost-Effectiveness 
PLoS ONE  2014;9(1):e85197.
Mobile HIV screening may facilitate early HIV diagnosis. Our objective was to examine the cost-effectiveness of adding a mobile screening unit to current medical facility-based HIV testing in Cape Town, South Africa.
Methods and Findings
We used the Cost Effectiveness of Preventing AIDS Complications International (CEPAC-I) computer simulation model to evaluate two HIV screening strategies in Cape Town: 1) medical facility-based testing (the current standard of care) and 2) addition of a mobile HIV-testing unit intervention in the same community. Baseline input parameters were derived from a Cape Town-based mobile unit that tested 18,870 individuals over 2 years: prevalence of previously undiagnosed HIV (6.6%), mean CD4 count at diagnosis (males 423/µL, females 516/µL), CD4 count-dependent linkage to care rates (males 31%–58%, females 49%–58%), mobile unit intervention cost (includes acquisition, operation and HIV test costs, $29.30 per negative result and $31.30 per positive result). We conducted extensive sensitivity analyses to evaluate input uncertainty. Model outcomes included site of HIV diagnosis, life expectancy, medical costs, and the incremental cost-effectiveness ratio (ICER) of the intervention compared to medical facility-based testing. We considered the intervention to be “very cost-effective” when the ICER was less than South Africa's annual per capita Gross Domestic Product (GDP) ($8,200 in 2012). We projected that, with medical facility-based testing, the discounted (undiscounted) HIV-infected population life expectancy was 132.2 (197.7) months; this increased to 140.7 (211.7) months with the addition of the mobile unit. The ICER for the mobile unit was $2,400/year of life saved (YLS). Results were most sensitive to the previously undiagnosed HIV prevalence, linkage to care rates, and frequency of HIV testing at medical facilities.
The addition of mobile HIV screening to current testing programs can improve survival and be very cost-effective in South Africa and other resource-limited settings, and should be a priority.
PMCID: PMC3898963  PMID: 24465503
24.  The impact of mass media interventions on tuberculosis awareness, health-seeking behaviour and health service utilisation: a systematic review protocol 
BMJ Open  2014;4(1):e004302.
Tuberculosis (TB) is a serious public health problem in many parts of the world. Strategies to curb the spread of TB must match the multifaceted nature of the epidemic. The use of mass media is one of the important strategies in communicating behavioural change in relation to TB prevention and the treatment. However, the benefits of this intervention are unclear. We, therefore, plan to conduct a systematic review on the effects of mass media interventions on TB awareness, health-seeking behaviour and health service utilisation.
Methods and analysis
We will preferably include randomised controlled trials (RCTs) in this systematic review. However, non-randomised studies will be included if there is an inadequate number of RCTs. We will perform electronic searches in PubMed, Scopus and other databases, along with manual searches. Articles written (or translated) in English and French and published between 1 January 1980 and 31 October 2013 will be eligible for inclusion in this review. The primary outcomes will be TB knowledge, attitudes and awareness, healthcare-seeking behaviour and service utilisation. The secondary outcomes will include stigma and discrimination against people with TB and the costs of the interventions. We will investigate clinical and statistical heterogeneity and pool studies judged to be clinically and statistically homogeneous. Relative risks will be calculated for dichotomous outcomes and mean differences for continuous outcomes, both with their corresponding 95% CIs.
Ethics and dissemination
The systematic review will use data that is not linked to individuals. The review findings may have implications for clinical practice and future research, and will be disseminated electronically and in print through peer-reviewed publications.
Protocol registration number
PROSPERO CRD42013005867
PMCID: PMC3902379  PMID: 24430882
25.  Is Obesity a Risk Factor for Vaccine Non-Responsiveness? 
PLoS ONE  2013;8(12):e82779.
Understanding the link between vaccine immunogenicity and efficacy is currently a major focus in HIV research. Consequently, recent developments in the HIV-1 vaccine field have led to a closer look at immune responses to known efficacious vaccines. We undertook a study to explore clinical predictors of vaccine efficacy following recombinant hepatitis B (rHBV) vaccination in a cohort of HIV-uninfected, hepatitis B virus naïve women living in a peri-urban setting in Cape Town. Our aim was to define host biological risk factors associated with lack of vaccine uptake. We found a significant association (p=0.009) between body mass index (BMI) and lack of vaccine-specific IgG titre (<10mIU/mL). Obese individuals (BMI ≥ 30kg/m2) were significantly more likely to be non-responders following 2 rHBV vaccine doses (Adjusted Odds Ratio of 8.75; p=0.043). There was no observed association between vaccine responses and age, method of contraception or time from vaccination to antibody measurement. These data suggest that obesity-associated factors interfere with vaccine immunogenicity and possible efficacy.
PMCID: PMC3859613  PMID: 24349359

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