Antiretroviral therapy and TB notification rates in a high HIV prevalence South African community

Incidence of self-reported tuberculosis treatment with community-wide universal testing and treatment for HIV and tuberculosis screening in Zambia and South Africa: A planned analysis of the HPTN 071 (PopART) cluster-randomised trial

BACKGROUND

HIV is a potent risk factor for tuberculosis (TB). Therefore, community-wide universal testing and treatment for HIV (UTT) could contribute to TB control, but evidence for this is limited. Community-wide TB screening can decrease population-level TB prevalence. Combining UTT with TB screening could therefore significantly impact TB control in sub-Saharan Africa, but to our knowledge there is no evidence for this combined approach.

METHODS AND FINDINGS

HPTN 071 (PopART) was a community-randomised trial conducted between November 2013 to July 2018; 21 Zambian and South African communities (with a total population of approximately 1 million individuals) were randomised to arms A (community-wide UTT and TB screening), B (community-wide universal HIV testing with treatment following national guidelines and TB screening), or C (standard-of-care). In a cohort of randomly selected adults (18 to 44 years) enrolled between 2013 and 2015 from all 21 communities (total size 38,474; 27,139 [71%] female; 8,004 [21%] HIV positive) and followed-up annually for 36 months to measure the population-level impact of the interventions, data on self-reported TB treatment in the previous 12 months (self-reported TB) were collected by trained research assistants and recorded using a structured questionnaire at each study visit. In this prespecified analysis of the trial, self-reported TB incidence rates were measured by calendar year between 2014 and 2017/2018. A p-value ≤0.05 on hypothesis testing was defined as reaching statistical significance. Between January 2014 and July 2018, 38,287 individuals were followed-up: 494 self-reported TB during 104,877 person-years. Overall incidence rates were similar across all arms in 2014 and 2015 (0.33 to 0.46/100 person-years). In 2016 incidence rates were lower in arm A compared to C overall (adjusted rate ratio [aRR] 0.48 [95% confidence interval (95% CI) 0.28 to 0.81; p = 0.01]), with statistical significance reached. In 2017/2018, while incidence rates were lower in arm A compared to C, statistical significance was not reached (aRR 0.58 [95% CI 0.27 to 1.22; p = 0.13]). Among people living with HIV (PLHIV) incidence rates were lower in arm A compared to C in 2016 (RR 0.56 [95% CI 0.29 to 1.08; p = 0.08]) and 2017/2018 (RR 0.50 [95% CI 0.26 to 0.95; p = 0.04]); statistical significance was only reached in 2017/2018. Incidence rates in arms B and C were similar, overall and among PLHIV. Among HIV-negative individuals, there were too few events for cross-arm comparisons. Study limitations include the use of self-report which may have been subject to under-reporting, limited covariate adjustment due to the small number of events, and high losses to follow-up over time.

CONCLUSIONS

In this study, community-wide UTT and TB screening resulted in substantially lower TB incidence among PLHIV at population-level, compared to standard-of-care, with statistical significance reached in the final study year. There was also some evidence this translated to a decrease in self-reported TB incidence overall in the population. Reduction in arm A but not B suggests UTT drove the observed effect. Our data support the role of UTT in TB control, in addition to HIV control, in high TB/HIV burden settings.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01900977.

Importance of ventilation and occupancy to Mycobacterium tuberculosis transmission rates in congregate settings

BACKGROUND

Ventilation rates are a key determinant of the transmission rate of Mycobacterium tuberculosis and other airborne infections. Targeting infection prevention and control (IPC) interventions at locations where ventilation rates are low and occupancy high could be a highly effective intervention strategy. Despite this, few data are available on ventilation rates and occupancy in congregate locations in high tuberculosis burden settings.

METHODS

We collected carbon dioxide concentration and occupancy data in congregate locations and public transport on 88 occasions, in Cape Town, South Africa. For each location, we estimated ventilation rates and the relative rate of infection, accounting for ventilation rates and occupancy.

RESULTS

We show that the estimated potential transmission rate in congregate settings and public transport varies greatly between different settings. Overall, in the community we studied, estimated infection risk was higher in minibus taxis and trains than in salons, bars, and shops. Despite good levels of ventilation, infection risk could be high in the clinic due to high occupancy levels.

CONCLUSION

Public transport in particular may be promising targets for infection prevention and control interventions in this setting, both to reduce Mtb transmission, but also to reduce the transmission of other airborne pathogens such as measles and SARS-CoV-2.

Environmental air sampling for detection and quantification of Mycobacterium tuberculosis in clinical settings: Proof of concept

Objective:

Novel approaches are needed to understand and disrupt Mycobacterium tuberculosis transmission. In this proof-of-concept study, we investigated the use of environmental air samplings to detect and quantify M. tuberculosis in different clinic settings in a high-burden area.

Design:

Cross-sectional, environmental sampling.

Setting:

Primary-care clinic.

Methods:

A portable, high-flow dry filter unit (DFU) was used to draw air through polyester felt filters for 2 hours. Samples were collected in the waiting area and TB room of a primary care clinic. Controls included sterile filters placed directly into collection tubes at the DFU sampling site, and filter samplings performed outdoors. DNA was extracted from the filters, and droplet digital polymerase chain reaction (ddPCR) was used to quantify M. tuberculosis DNA copies. Carbon dioxide (CO2) data loggers captured CO2 concentrations in the sampled areas.

Results:

The median sampling time was 123 minutes (interquartile range [IQR], 121–126). A median of 121 (IQR, 35–243) M. tuberculosis DNA copies were obtained from 74 clinic samplings, compared to a median of 3 (IQR, 1–33; P < .001) obtained from 47 controls. At a threshold of 320 DNA copies, specificity was 100%, and 18% of clinic samples would be classified as positive.

Conclusions:

This proof-of-concept study suggests that the potential for airborne M. tuberculosis detection based on M. tuberculosis DNA copy yield to enable the identification of high-risk transmission locations. Further optimization of the M. tuberculosis extraction technique and ddPCR data analysis would improve detection and enable robust interpretation of these data.

Estimating Tuberculosis Transmission Risks in a Primary Care Clinic in South Africa: Modeling of Environmental and Clinical Data

BACKGROUND

Congregate settings, such as healthcare clinics, may play an essential role in Mycobacterium tuberculosis (Mtb) transmission. Using patient and environmental data, we studied transmission at a primary care clinic in South Africa.

METHODS

We collected patient movements, cough frequency, and clinical data, and measured indoor carbon dioxide (CO2) levels, relative humidity, and Mtb genomes in the air. We used negative binomial regression model to investigate associations.

RESULTS

We analyzed 978 unique patients who contributed 14 795 data points. The median patient age was 33 (interquartile range [IQR], 26-41) years, and 757 (77.4%) were female. Overall, median CO2 levels were 564 (IQR 495-646) parts per million and were highest in the morning. Median number of coughs per day was 466 (IQR, 368-503), and overall median Mtb DNA copies/μL/day was 4.2 (IQR, 1.2-9.5). We found an increased presence of Mtb DNA in the air of 32% (95% credible interval, 7%-63%) per 100 additional young adults (aged 15-29 years) and 1% (0-2%) more Mtb DNA per 10% increase of relative humidity. Estimated cumulative transmission risks for patients attending the clinic monthly for at least 1 hour range between 9% and 29%.

CONCLUSIONS

We identified young adults and relative humidity as potentially important factors for transmission risks in healthcare clinics. Our approach should be used to detect transmission and evaluate infection control interventions.

HIV-associated tuberculosis

Tuberculosis (TB) remains a leading cause of morbidity and mortality among people living with HIV. HIV-associated TB disproportionally affects African countries, particularly vulnerable groups at risk for both TB and HIV. Currently available TB diagnostics perform poorly in people living with HIV; however, new diagnostics such as Xpert Ultra and lateral flow urine lipoarabinomannan assays can greatly facilitate diagnosis of TB in people living with HIV. TB preventive treatment has been underutilized despite its proven benefits independent of antiretroviral therapy (ART). Shorter regimens using rifapentine can support increased availability and scale-up. Mortality is high in people with HIV-associated TB, and timely initiation of ART is critical. Programs should provide decentralized and integrated TB and HIV care in settings with high burden of both diseases to improve access to services that diagnose TB and HIV as early as possible. The new prevention and diagnosis tools recently recommended by WHO offer an immense opportunity to advance our fight against HIV-associated TB. They should be made widely available and scaled up rapidly supported by adequate funding with robust monitoring of the uptake to advance global TB elimination.

The scale-up of antiretroviral therapy coverage was strongly associated with the declining tuberculosis morbidity in Africa during 2000-2018

OBJECTIVES

Antiretroviral therapy (ART) reduces the risk of tuberculosis (TB). We aimed to examine the association between ART coverage scale-up on the changes in TB incidence in Africa from 2000 to 2018.

STUDY DESIGN

The design of the study is a retrospective ecological study.

METHODS

Data for 54 countries were obtained from several institutional-based sources, including the World Health Organization, the Joint United Nations Programme on HIV/AIDS, and the World Bank. A fixed-effects regression method of longitudinal data analysis was used to estimate the association between ART coverage and changes in TB incidence rate during 2000-2018. Statistical analyses were conducted using STATA 15.0/IC.

RESULTS

The TB incidence declined significantly, by an average of 2.3% per year during 2000-2018. The highest significant declines occurred in eastern and southern Africa. In adjusted analysis, each 1% increase in ART coverage was associated with a 3.97 per 100,000 decline of TB incidence. However, the marginal effects of ART on overall population TB incidence was dependent on the prevalence of human immunodeficiency virus infection.

CONCLUSIONS

Investment in the widespread scale-up of ART may contribute to the control of the TB epidemic in Africa. However, interventions are also needed to augment the effect of ART on population TB incidence.

Novel approach to estimate tuberculosis transmission in primary care clinics in sub-Saharan Africa: protocol of a prospective study

INTRODUCTION

Tuberculosis (TB) transmission is difficult to measure, and its drivers are not well understood. The effectiveness of infection control measures at healthcare clinics and the most appropriate intervention strategies to interrupt transmission are unclear. We propose a novel approach using clinical, environmental and position-tracking data to study the risk of TB transmission at primary care clinics in TB and HIV high burden settings in sub-Saharan Africa.

METHODS AND ANALYSIS

We describe a novel and rapid study design to assess risk factors for airborne TB transmission at primary care clinics in high-burden settings. The study protocol combines a range of different measurements. We will collect anonymous data on the number of patients, waiting times and patient movements using video sensors. Also, we will collect acoustic sound recordings to determine the frequency and intensity of coughing. Environmental data will include indoor carbon dioxide levels (CO₂ in parts per million) and relative humidity. We will also extract routinely collected clinical data from the clinic records. The number of Mycobacterium tuberculosis particles in the air will be ascertained from dried filter units using highly sensitive digital droplet PCR. We will calculate rebreathed air volume based on people density and CO₂ levels and develop a mathematical model to estimate the risk of TB transmission. The mathematical model can then be used to estimate the effect of possible interventions such as separating patient flows or improving ventilation in reducing transmission. The feasibility of our approach was recently demonstrated in a pilot study in a primary care clinic in Cape Town, South Africa.

ETHICS AND DISSEMINATION

The study was approved by the University of Cape Town (HREC/REF no. 228/2019), the City of Cape Town (ID-8139) and the Ethics Committee of the Canton Bern (2019-02131), Switzerland. The results will be disseminated in international peer-reviewed journals.

Trend analysis of tuberculosis case notifications with scale-up of antiretroviral therapy and roll-out of isoniazid preventive therapy in Zimbabwe, 2000-2018

OBJECTIVES

Antiretroviral therapy (ART) and isoniazid preventive therapy (IPT) are known to have a tuberculosis (TB) protective effect at the individual level among people living with HIV (PLHIV). In Zimbabwe where TB is driven by HIV infection, we have assessed whether there is a population-level association between IPT and ART scale-up and annual TB case notification rates (CNRs) from 2000 to 2018.

DESIGN

Ecological study using aggregate national data.

SETTING

Annual aggregate national data on TB case notification rates (stratified by TB category and type of disease), numbers (and proportions) of PLHIV in ART care and of these, numbers (and proportions) ever commenced on IPT.

RESULTS

ART coverage in the public sector increased from <1% (8400 PLHIV) in 2004 to ~88% (>1.1 million PLHIV patients) by December 2018, while IPT coverage among PLHIV in ART care increased from <1% (98 PLHIV) in 2012 to ~33% (373 917 PLHIV) by December 2018. These HIV-related interventions were associated with significant declines in TB CNRs: between the highest CNR prior to national roll-out of ART (in 2004) to the lowest recorded CNR after national IPT roll-out from 2012, these were (1) for all TB case (510 to 173 cases/100 000 population; 66% decline, p<0.001); (2) for those with new TB (501 to 159 cases/100 000 population; 68% decline, p<0.001) and (3) for those with new clinically diagnosed PTB (284 to 63 cases/100 000 population; 77.8% decline, p<0.001).

CONCLUSIONS

This study shows the population-level impact of the continued scale-up of ART among PLHIV and the national roll-out of IPT among those in ART care in reducing TB, particularly clinically diagnosed TB which is largely associated with HIV. There are further opportunities for continued mitigation of TB with increasing coverage of ART and in particular IPT which still has a low coverage.

TB transmission is associated with prolonged stay in a low socio-economic, high burdened TB and HIV community in Cape Town, South Africa

Background

While several studies have assessed the associations between biological factors and tuberculosis (TB) transmission, our understanding of the associations between TB transmission and social and economic factors remains incomplete. We aimed to explore associations between community TB transmission and socio-economic factors within a high TB-HIV burdened setting.

Methods

We conducted a cross-sectional molecular epidemiology study among adult patients attending a routine TB clinic. Demographic and clinical data were extracted from TB registers and clinical folders; social and economic data were collected using interviewer-administered questionnaires; Mycobacterium tuberculosis isolates were genotyped and classified as clustered/non-clustered using IS6110-based Restriction Fragment Length Polymorphism. Composite “social” and “economic” scores were generated from social and economic data. Data were analyzed using StataCorp version 15.0 software. Stratified, bivariable analyses were performed using chi-squared. Wilcoxon signed rank tests; univariable and multivariable logistic regression models were developed to explore associations in the social, economic, traditional and composite TB risk factors with TB transmission.

Results

Of the 505 patient Mtb  strains, 348(69%) cases were classified as clustered and 157(31%) were non-clustered. Clustered cases were more likely to have lived longer in the study community, (odds ratio [OR] = 1.05, 95% Confidence interval [C.I]:1.02–1.09, p = 0.006); in the same house (OR = 1.04, C.I: 0.99–1.08, p = 0.06); and had increased household crowding conditions (i.e fewer rooms used for sleeping, OR = 0.45, C.I:0.21–0.95, p = 0.04). Although a higher proportion of clustered cases had a low economic score, no statistically significant association was found between clustering and either the economic score (p = 0.13) or social score (p = 0.26).

Conclusions

We report a novel association between Mtb transmission and prolonged stay within a high burdened community. Transmission was also associated with fewer rooms for sleeping in a household. Increased social interaction and prolonged residence in a high burdened community are important factors linked to Mtb transmission, possibly due to increased probability of higher effective contact rates. The possible importance of degrees of poverty within low socio-economic setting warrants further study.

Decreased risk of HIV-associated TB during antiretroviral therapy expansion in rural Eswatini from 2009 to 2016: a cohort and population-based analysis

OBJECTIVES

This paper assesses patient- and population-level trends in TB notifications during rapid expansion of antiretroviral therapy in Eswatini which has an extremely high incidence of both TB and HIV.

METHODS

Patient- and population-level predictors and rates of HIV-associated TB were examined in the Shiselweni region in Eswatini from 2009 to 2016. Annual population-level denominators obtained from projected census data and prevalence estimates obtained from population-based surveys were combined with individual-level TB treatment data. Patient- and population-level predictors of HIV-associated TB were assessed with multivariate logistic and multivariate negative binomial regression models.

RESULTS

Of 11 328 TB cases, 71.4% were HIV co-infected and 51.8% were women. TB notifications decreased fivefold between 2009 and 2016, from 1341 to 269 cases per 100 000 person-years. The decline was sixfold in PLHIV vs. threefold in the HIV-negative population. Main patient-level predictors of HIV-associated TB were recurrent TB treatment (adjusted odds ratio [aOR] 1.40, 95% confidence interval [CI]: 1.19-1.65), negative (aOR 1.31, 1.15-1.49) and missing (aOR 1.30, 1.11-1.53) bacteriological status and diagnosis at secondary healthcare level (aOR 1.18, 1.06-1.33). Compared with 2009, the probability of TB decreased for all years from 2011 (aOR 0.69, 0.58-0.83) to 2016 (aOR 0.54, 0.43-0.69). The most pronounced population-level predictor of TB was HIV-positive status (adjusted incidence risk ratio 19.47, 14.89-25.46).

CONCLUSIONS

This high HIV-TB prevalence setting experienced a rapid decline in TB notifications, most pronounced in PLHIV. Achievements in HIV-TB programming were likely contributing factors.

Space-time clustering of recently-diagnosed tuberculosis and impact of ART scale-up: Evidence from an HIV hyper-endemic rural South African population

In HIV hyperendemic sub-Saharan African communities, particularly in southern Africa, the likelihood of achieving the Sustainable Development Goal of ending the tuberculosis (TB) epidemic by 2030 is low, due to lack of cost-effective and practical interventions in population settings. We used one of Africa’s largest population-based prospective cohorts from rural KwaZulu-Natal Province, South Africa, to measure the spatial variations in the prevalence of recently-diagnosed TB disease, and to quantify the impact of community coverage of antiretroviral therapy (ART) on recently-diagnosed TB disease. We collected data on TB disease episodes from a population-based sample of 41,812 adult individuals between 2009 and 2015. Spatial clusters (‘hotspots’) of recently-diagnosed TB were identified using a space-time scan statistic. Multilevel logistic regression models were fitted to investigate the relationship between community ART coverage and recently-diagnosed TB. Spatial clusters of recently-diagnosed TB were identified in a region characterized by a high prevalence of HIV and population movement. Every percentage increase in ART coverage was associated with a 2% decrease in the odds of recently-diagnosed TB (aOR = 0.98, 95% CI:0.97–0.99). We identified for the first time the clear occurrence of recently-diagnosed TB hotspots, and quantified potential benefit of increased community ART coverage in lowering tuberculosis, highlighting the need to prioritize the expansion of such effective population interventions targeting high-risk areas.

Tuberculosis decline in populations affected by HIV: a retrospective study of 12 countries in the WHO African Region

Objective

To investigate which of the World Health Organization recommended methods for tuberculosis control have had the greatest effect on case incidence in 12 countries in the World Health Organization (WHO) African Region that carry high burdens of tuberculosis linked to human immunodeficiency virus (HIV) infection.

Methods

We obtained epidemiological surveillance, survey and treatment data on HIV and tuberculosis for the years 2003 to 2016. We used statistical models to examine the effects of antiretroviral therapy (ART) and isoniazid preventive therapy in reducing the incidence of tuberculosis among people living with HIV. We also investigated the role of tuberculosis case detection and treatment in preventing Mycobacterium tuberculosis transmission and consequently reducing tuberculosis incidence.

Findings

Between 2003 and 2016, ART provision was associated with the decline of tuberculosis in each country, and with differences in tuberculosis decline between countries. Inferring that ART was a cause of tuberculosis decline, ART prevented 1.88 million (95% confidence interval, CI: 1.65 to 2.11) tuberculosis cases in people living with HIV, or 15.7% (95% CI: 13.8 to 17.6) of the 11.96 million HIV-positive tuberculosis cases expected. Population coverage of isoniazid preventive therapy was too low (average 1.0% of persons eligible) to have a major effect on tuberculosis decline, and improvements in tuberculosis detection and treatment were either weakly associated or not significantly associated with tuberculosis decline.

Conclusion

ART provision is associated with tuberculosis decline in these 12 countries. ART should remain central to tuberculosis control where rates of tuberculosis–HIV coinfection are high, but renewed efforts to treat tuberculosis are needed.

Assessing the impact of antiretroviral therapy on tuberculosis notification rates among people with HIV: a descriptive analysis of 23 countries in sub-Saharan Africa, 2010-2015

BACKGROUND

HIV is a major driver of the tuberculosis epidemic in sub-Saharan Africa. The population-level impact of antiretroviral therapy (ART) scale-up on tuberculosis rates in this region has not been well studied. We conducted a descriptive analysis to examine evidence of population-level effect of ART on tuberculosis by comparing trends in estimated tuberculosis notification rates, by HIV status, for countries in sub-Saharan Africa.

METHODS

We estimated annual tuberculosis notification rates, stratified by HIV status during 2010-2015 using data from WHO, the Joint United Nations Programme on HIV/AIDS, and the United Nations Population Division. Countries were included in this analysis if they had ≥4 years of HIV prevalence estimates and ≥ 75% of tuberculosis patients with known HIV status. We compared tuberculosis notification rates among people living with HIV (PLHIV) and people without HIV via Wilcoxon rank sum test.

RESULTS

Among 23 included countries, the median annual average change in tuberculosis notification rates among PLHIV during 2010-2015 was -5.7% (IQR -6.9 to -1.7%), compared to a median change of -2.3% (IQR -4.2 to -0.1%) among people without HIV (p-value = 0.0099). Among 11 countries with higher ART coverage, the median annual average change in TB notification rates among PLHIV was -6.8% (IQR -7.6 to -5.7%) compared to a median change of -2.1% (IQR -6.0 to 0.7%) for PLHIV in 12 countries with lower ART coverage (p = 0.0106).

CONCLUSION

Tuberculosis notification rates declined more among PLHIV than people without HIV, and have declined more in countries with higher ART coverage. These results are consistent with a population-level effect of ART on decreasing TB incidence among PLHIV. To further reduce TB incidence among PLHIV, additional scale-up of ART as well as greater use of isoniazid preventive therapy and active case-finding will be necessary.

Immunological non-response and low hemoglobin levels are predictors of incident tuberculosis among HIV-infected individuals on Truvada-based therapy in Botswana

Background

There is a high burden of tuberculosis (TB) in HIV antiretroviral programmes in Africa. However, few studies have looked at predictors of incident TB while on Truvada-based combination antiretroviral therapy (cART) regimens.

Methods

We estimated TB incidence among individuals enrolled into an observational cohort evaluating the efficacy and tolerability of Truvada-based cART in Gaborone, Botswana between 2008 and 2011. We used Cox proportional hazards regressions to determine predictors of incident TB.

Results

Of 300 participants enrolled, 45 (15%) had a diagnosis of TB at baseline. During 428 person-years (py) of follow-up, the incidence rate of TB was 3.04/100py (95% CI, 1.69–5.06), with 60% of the cases occurring within 3 months of ART initiation. Incident cases had low baseline CD4+ T cell counts (153cells/mm³ [Q1, Q3: 82, 242]; p = 0.69) and hemoglobin levels (9.2g/dl [Q1, Q3: 8.5,10.1]; p<0.01). In univariate analysis, low BMI (HR = 0.73; 95% CI 0.58–0.91; p = 0.01) and hemoglobin levels <8 g/dl (HR = 10.84; 95%CI: 2.99–40.06; p<0.01) were risk factors for TB. Time to incident TB diagnosis was significantly reduced in patients with poor immunological recovery (p = 0.04). There was no association between baseline viral load and risk of TB (HR = 1.75; 95%CI: 0.70–4.37).

Conclusion

Low hemoglobin levels prior to initiation of ART are significant predictors of incident tuberculosis. Therefore, there is potential utility of iron biomarkers to identify patients at risk of TB prior to initiation on ART. Furthermore, additional strategies are required for patients with poor immunological recovery to reduce excess risk of TB while on ART.

Scale-up of ART in Malawi has reduced case notification rates in HIV-positive and HIV-negative tuberculosis

Setting: For 30 years, Malawi has experienced a dual epidemic of human immunodeficiency virus (HIV) infection and tuberculosis (TB) that has recently begun to be attenuated by the scale-up of antiretroviral therapy (ART). Objective: To report on the correlation between ART scale-up and annual national TB case notification rates (CNR) in Malawi, stratified by HIV-positive and HIV-negative status, from 2005 to 2015. Design: A retrospective descriptive ecological study using aggregate data from national reports. Results: From 2005 to 2015, ART was scaled up in Malawi from 28 470 to 618 488 total patients, with population coverage increasing from 2.4% to 52.2%. During this time, annual TB notifications declined by 35%, from 26 344 to 17 104, and the TB CNR per 100 000 population declined by 49%, from 206 to 105. HIV testing uptake increased from 51% to 92%. In known HIV-positive TB patients, the CNR decreased from a high of 1247/100 000 to 710/100 000, a 43% decrease. In known HIV-negative TB patients, the CNR also decreased, from a high of 66/100 000 to 49/100 000, a 26% decrease. Conclusion: TB case notifications have continued to decline in association with ART scale-up, with the decline seen more in HIV-positive than HIV-negative TB. These findings have programmatic implications for national TB control efforts.

High mortality in tuberculosis patients despite HIV interventions in Swaziland

SETTING

All health facilities providing tuberculosis (TB) care in Swaziland.

OBJECTIVE

To describe the impact of human immunodeficiency virus (HIV) interventions on the trend of TB treatment outcomes during 2010-2013 in Swaziland; and to describe the evolution in TB case notification, the uptake of HIV testing, antiretroviral therapy (ART) and cotrimoxazole preventive therapy (CPT), and the proportion of TB-HIV co-infected patients with adverse treatment outcomes, including mortality, loss to follow-up and treatment failure.

DESIGN

A retrospective descriptive study using aggregated national TB programme data.

RESULTS

Between 2010 and 2013, TB case notifications in Swaziland decreased by 40%, HIV testing increased from 86% to 96%, CPT uptake increased from 93% to 99% and ART uptake among TB patients increased from 35% to 75%. The TB-HIV co-infection rate remained around 70% and the proportion of TB-HIV cases with adverse outcomes decreased from 36% to 30%. Mortality remained high, at 14-16%, over the study period, and anti-tuberculosis treatment failure rates were stable over time (<5%).

CONCLUSION

Despite high CPT and ART uptake in TB-HIV patients, mortality remained high. Further studies are required to better define high-risk patient groups, understand the reasons for death and design appropriate interventions.

Brief Report: The Effect of Antiretroviral Therapy and CD4 Count on Markers of Infectiousness in HIV-Associated Tuberculosis

Clinical features of tuberculosis influence infectiousness. This cross-sectional study examined the effect of combination antiretroviral therapy (cART) and CD4 on sputum smear-positivity (SS+) and pulmonary cavitation among 1589 (1185/1589 HIV-positive) miners in South Africa. Proportions SS+ varied nonlinearly by CD4 with greatest proportions SS+ (55.3%) in the lowest stratum (<100 cells/μL). Adjusted prevalence ratio for SS+; on vs. off cART was 0.90 (95% confidence interval: 0.73 to 1.11). Proportions with cavitation varied linearly with CD4, with no independent cART effect (adjusted prevalence ratio 1.17; 95% confidence interval: 0.80 to 1.71). cART did not independently affect SS+ or cavitation but may increase infectiousness through CD4 recovery.

Benefits of combined preventive therapy with co-trimoxazole and isoniazid in adults living with HIV: time to consider a fixed-dose, single tablet coformulation

Antiretroviral therapy (ART) is the main intervention needed to reduce morbidity and mortality and to prevent tuberculosis in adults living with HIV. However, in most resource-limited countries, especially in sub-Saharan Africa, ART is started too late to have an effect with substantial early morbidity and mortality, and in high tuberculosis burden settings ART does not reduce the tuberculosis risk to that reported in individuals not infected with HIV. Co-trimoxazole preventive therapy started before or with ART, irrespective of CD4 cell count, reduces morbidity and mortality with benefits that continue indefinitely. Isoniazid preventive therapy as an adjunct to ART prevents tuberculosis in high-exposure settings, with long-term treatment likely to be needed to sustain this benefit. Unfortunately, both preventive therapies are underused in low-income and high-burden settings. ART development has benefited from patient-centred simplification with several effective regimens now available as a one per day pill. We argue that co-trimoxazole and isoniazid should also be combined into a single fixed-dose pill, along with pyridoxine (vitamin B6), that would be taken once per day to help with individual uptake and national scale-up of therapies.

Temporal trends in TB notification rates during ART scale-up in Cape Town: an ecological analysis

INTRODUCTION

Although antiretroviral therapy (ART) reduces individual tuberculosis (TB) risk by two-thirds, the population-level impact remains uncertain. Cape Town reports high TB notification rates associated with endemic HIV. We examined population trends in TB notification rates during a 10-year period of expanding ART.

METHODS

Annual Cape Town TB notifications were used as numerators and mid-year Cape Town populations as denominators. HIV-stratified population was calculated using overall HIV prevalence estimates from the Actuarial Society of South Africa AIDS and Demographic model. ART provision numbers from Western Cape government reports were used to calculate overall ART coverage. We calculated rates per 100,000 population over time, overall and stratified by HIV status. Rates per 100,000 total population were also calculated by ART use at treatment initiation. Absolute numbers of notifications were compared by age and sub-district. Changes over time were described related to ART provision in the city as a whole (ART coverage) and by sub-district (numbers on ART).

RESULTS

From 2003 to 2013, Cape Town's population grew from 3.1 to 3.7 million inhabitants, and estimated HIV prevalence increased from 3.6 to 5.2%. ART coverage increased from 0 to 63% in 2013. TB notification rates declined by 16% (95% confidence interval (CI), 14-17%) from a 2008 peak (851/100,000) to a 2013 nadir (713/100,000). Decreases were higher among the HIV-positive (21% (95% CI, 19-23%)) than the HIV-negative (9% (95% CI, 7-11%)) population. The number of HIV-positive TB notifications decreased mainly among 0- to 4- and 20- to 34-year-olds. Total population rates on ART at TB treatment initiation increased over time but levelled off in 2013. Overall median CD4 counts increased from 146 cells/µl (interquartile range (IQR), 66, 264) to 178 cells/µl (IQR 75, 330; p<0.001). Sub-district antenatal HIV seroprevalence differed (10-33%) as did numbers on ART (9-29 thousand). Across sub-districts, infant HIV-positive TB decreased consistently whereas adult decreases varied.

CONCLUSIONS

HIV-positive TB notification rates declined during a period of rapid scale-up of ART. Nevertheless, both HIV-positive and HIV-negative TB notification rates remained very high. Decreases among HIV positives were likely blunted by TB remaining a major entry to the ART programme and occurring after delayed ART initiation.

Decline in national tuberculosis notifications with national scale-up of antiretroviral therapy in Malawi

From 2000 to 2012, Malawi scaled up antiretroviral therapy (ART) from <3000 to 404 905 persons living with HIV/AIDS (human immunodeficiency virus/acquired immune-deficiency syndrome), representing an ART coverage of 40.6% among those living with HIV. During this time, annual tuberculosis (TB) notifications declined by 28%, from 28 234 to 20 463. Percentage declines in annual TB case notifications were as follows: new TB (26%), recurrent TB (40%), new smear-positive pulmonary TB (19%), new smear-negative pulmonary TB (42%), extra-pulmonary TB (19%), HIV-positive TB (30%) and HIV-negative TB (10%). The decline in TB notifications is associated with ART scale-up, supporting its value in controlling TB in high HIV prevalence areas in sub-Saharan Africa.

Cost-effectiveness of the Three I's for HIV/TB and ART to prevent TB among people living with HIV

OBJECTIVE

To evaluate the cost-effectiveness of the Three I's for HIV/TB (human immunodeficiency virus/tuberculosis): antiretroviral therapy (ART), intensified TB case finding (ICF), isoniazid preventive treatment (IPT), and TB infection control (IC).

METHODS

Using a 3-year decision-analytic model, we estimated the cost-effectiveness of a base scenario (55% ART coverage at CD4 count ⩿350 cells/mm(3)) and 19 strategies that included one or more of the following: 1) 90% ART coverage, 2) IC and 3) ICF using four-symptom screening and 6- or 36-month IPT. The TB diagnostic algorithm included 1) sputum smear microscopy with chest X-ray, and 2) Xpert® MTB/RIF.

RESULTS

In resource-constrained settings with a high burden of HIV and TB, the most cost-effective strategies under both diagnostic algorithms included 1) 55% ART coverage and IC, 2) 55% ART coverage, IC and 36-month IPT, and 3) expanded ART at 90% coverage with IC and 36-month IPT. The latter averted more TB cases than other scenarios with increased ART coverage, IC, 6-month IPT and/or IPT for tuberculin skin test positive individuals. The cost-effectiveness results did not change significantly under the sensitivity analyses.

CONCLUSION

Expanded ART to 90% coverage, IC and a 36-month IPT strategy averted most TB cases and is among the cost-effective strategies.

A Bundle of Services Increased Ascertainment of Tuberculosis among HIV-Infected Individuals Enrolled in a HIV Cohort in Rural Sub-Saharan Africa

OBJECTIVES

To report on trends of tuberculosis ascertainment among HIV patients in a rural HIV cohort in Tanzania, and assessing the impact of a bundle of services implemented in December 2012, consisting of three components: (i) integration of HIV and tuberculosis services; (ii) GeneXpert for tuberculosis diagnosis; and (iii) electronic data collection.

DESIGN

Retrospective cohort study of patients enrolled in the Kilombero Ulanga Antiretroviral Cohort (KIULARCO), Tanzania.).

METHODS

HIV patients without prior history of tuberculosis enrolled in the KIULARCO cohort between 2005 and 2013 were included.Cox proportional hazard models were used to estimate rates and predictors of tuberculosis ascertainment.

RESULTS

Of 7114 HIV positive patients enrolled, 5123 (72%) had no history of tuberculosis. Of these, 66% were female, median age was 38 years, median baseline CD4+ cell count was 243 cells/µl, and 43% had WHO clinical stage 3 or 4. During follow-up, 421 incident tuberculosis cases were notified with an estimated incidence of 3.6 per 100 person-years (p-y) [95% confidence interval (CI) 3.26-3.97]. The incidence rate varied over time and increased significantly from 2.96 to 43.98 cases per 100 p-y after the introduction of the bundle of services in December 2012. Four independent predictors of tuberculosis ascertainment were identified:poor clinical condition at baseline (Hazard Ratio (HR) 3.89, 95% CI 2.87-5.28), WHO clinical stage 3 or 4 (HR 2.48, 95% CI 1.88-3.26), being antiretroviralnaïve (HR 2.97, 95% CI 2.25-3.94), and registration in 2013 (HR 6.07, 95% CI 4.39-8.38).

CONCLUSION

The integration of tuberculosis and HIV services together with comprehensive electronic data collection and use of GeneXpert increased dramatically the ascertainment of tuberculosis in this rural African HIV cohort.

Adaptive pair-matching in randomized trials with unbiased and efficient effect estimation

In randomized trials, pair-matching is an intuitive design strategy to protect study validity and to potentially increase study power. In a common design, candidate units are identified, and their baseline characteristics used to create the best n/2 matched pairs. Within the resulting pairs, the intervention is randomized, and the outcomes measured at the end of follow-up. We consider this design to be adaptive, because the construction of the matched pairs depends on the baseline covariates of all candidate units. As a consequence, the observed data cannot be considered as n/2 independent, identically distributed pairs of units, as common practice assumes. Instead, the observed data consist of n dependent units. This paper explores the consequences of adaptive pair-matching in randomized trials for estimation of the average treatment effect, conditional the baseline covariates of the n study units. By avoiding estimation of the covariate distribution, estimators of this conditional effect will often be more precise than estimators of the marginal effect. We contrast the unadjusted estimator with targeted minimum loss based estimation and show substantial efficiency gains from matching and further gains with adjustment. This work is motivated by the Sustainable East Africa Research in Community Health study, an ongoing community randomized trial to evaluate the impact of immediate and streamlined antiretroviral therapy on HIV incidence in rural East Africa.

A combination strategy for enhancing linkage to and retention in HIV care among adults newly diagnosed with HIV in Mozambique: study protocol for a site-randomized implementation science study

BACKGROUND

Despite the extraordinary scale up of HIV prevention, care and treatment services in sub-Saharan Africa (SSA) over the past decade, the overall effectiveness of HIV programs has been significantly hindered by high levels of attrition across the HIV care continuum. Data from "real-life" settings are needed on the effectiveness of an easy to deliver package of services that can improve overall performance of the HIV care continuum.

METHODS/DESIGN

We are conducting an implementation science study using a two-arm cluster site-randomized design to determine the effectiveness of a combination intervention strategy (CIS) using feasible, evidence-based, and practical interventions-including (1) point-of-care (POC) CD4 count testing, (2) accelerated antiretroviral therapy initiation for eligible individuals, and (3) SMS reminders for linkage to and retention in care-as compared to the standard of care (SOC) in Mozambique in improving linkage and retention among adults following HIV diagnosis. A pre-post intervention two-sample design is nested within the CIS arm to assess the incremental effectiveness of the CIS plus financial incentives (CIS + FI) compared to the CIS without FI on study outcomes. Randomization is done at the level of the study site, defined as a primary health facility. Five sites are included from the City of Maputo and five from Inhambane Province. Target enrollment is a total of 2,250 adults: 750 in the SOC arm, 750 in the CIS cohort of the intervention arm and 750 in the CIS + FI cohort of the intervention arm (average of 150 participants per site). Participants are followed for 12 months from time of HIV testing to ascertain a combined endpoint of linkage to care within 1 month after testing and retention in care 12 months from HIV test. Cost-effectiveness analyses of CIS compared to SOC and CIS + FI compared to CIS will also be conducted.

DISCUSSION

Study findings will provide evidence on the effectiveness of a CIS and the incremental effectiveness of a CIS + FI in a "real-life" service delivery system in a SSA country severely impacted by HIV.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT01930084.

Quantification of shared air: a social and environmental determinant of airborne disease transmission

Background

Tuberculosis is endemic in Cape Town, South Africa where a majority of the population become tuberculosis infected before adulthood. While social contact patterns impacting tuberculosis and other respiratory disease spread have been studied, the environmental determinants driving airborne transmission have not been quantified.

Methods

Indoor carbon dioxide levels above outdoor levels reflect the balance of exhaled breath by room occupants and ventilation. We developed a portable monitor to continuously sample carbon dioxide levels, which were combined with social contact diary records to estimate daily rebreathed litres. A pilot study established the practicality of monitor use up to 48-hours. We then estimated the daily volumes of air rebreathed by adolescents living in a crowded township.

Results

One hundred eight daily records were obtained from 63 adolescents aged between 12- and 20-years. Forty-five lived in wooden shacks and 18 in brick-built homes with a median household of 4 members (range 2–9). Mean daily volume of rebreathed air was 120.6 (standard error: 8.0) litres/day, with location contributions from household (48%), school (44%), visited households (4%), transport (0.5%) and other locations (3.4%). Independent predictors of daily rebreathed volumes included household type (p = 0.002), number of household occupants (p = 0.021), number of sleeping space occupants (p = 0.022) and winter season (p<0.001).

Conclusions

We demonstrated the practical measurement of carbon dioxide levels to which individuals are exposed in a sequence of non-steady state indoor environments. A novel metric of rebreathed air volume reflects social and environmental factors associated with airborne infection and can identify locations with high transmission potential.

Transmission of tuberculosis in a South African community with a high prevalence of HIV infection

BACKGROUND

In settings of high tuberculosis transmission, little is known of the interaction between human immunodeficiency virus (HIV) positive and HIV-negative tuberculosis disease and of the impact of antiretroviral treatment (ART) programs on tuberculosis transmission dynamics.

METHODS

Mycobacterium tuberculosis isolates were collected from patients with tuberculosis who resided in a South African township with a high burden of tuberculosis and HIV infection. Demographic and clinical data were extracted from clinic records. Isolates underwent IS6110-based restriction fragment length polymorphism analysis. Patients with unique (nonclustered) M. tuberculosis genotypes and cluster index cases (ie, the first tuberculosis case in a cluster) were defined as having tuberculosis due to reactivation of latent M. tuberculosis infection. Secondary cases in clusters were defined as having tuberculosis due to recent M. tuberculosis infection.

RESULTS

Overall, 311 M. tuberculosis genotypes were identified among 718 isolates from 710 patients; 224 (31%) isolates were unique strains, and 478 (67%) occurred in 87 clusters. Cluster index cases were significantly more likely than other tuberculosis cases to be HIV negative. HIV-positive patients were more likely to be secondary cases (P = .001), including patients receiving ART (P = .004). Only 8% of cases of adult-adult transmission of tuberculosis occurred on shared residential plots.

CONCLUSIONS

Recent infection accounted for the majority of tuberculosis cases, particularly among HIV-positive patients, including patients receiving ART. HIV-negative patients may be disproportionally responsible for ongoing transmission.

Comparison of trends in tuberculosis incidence among adults living with HIV and adults without HIV--Kenya, 1998-2012

Background

In Kenya, the comparative incidences of tuberculosis among persons with and without HIV have not been described, and the differential impact of public health interventions on tuberculosis incidence in the two groups is unknown.

Methods

We estimated annual tuberculosis incidence stratified by HIV status during 2006–2012 based on the numbers of reported tuberculosis patients with and without HIV infection, the prevalence of HIV infection in the general population, and the total population. We also made crude estimates of annual tuberculosis incidence stratified by HIV status during 1998–2012 by assuming a constant ratio of HIV prevalence among tuberculosis patients compared to the general population.

Results

Tuberculosis incidence among both adults with HIV and adults without HIV increased during 1998–2004 then remained relatively stable until 2007. During 2007–2012, tuberculosis incidence declined by 28–44% among adults with HIV and by 11–26% among adults without HIV, concurrent with an increase in antiretroviral therapy uptake. In 2012, tuberculosis incidence among adults with HIV (1,839–1,936 cases/100,000 population) was still eight times as high as among adults without HIV (231–238 cases/100,000 population), and approximately one third of tuberculosis cases were attributable to HIV.

Conclusions

Although tuberculosis incidence has declined among adults with and without HIV, the persistent high incidence of tuberculosis among those with HIV and the disparity between the two groups are concerning. Early diagnosis of HIV, early initiation of antiretroviral therapy, regular screening for tuberculosis, and isoniazid preventive therapy among persons with HIV, as well as tuberculosis control in the general population, are required to address these issues.

Decreasing household contribution to TB transmission with age: a retrospective geographic analysis of young people in a South African township

Background

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.

Methods

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.

Results

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).

Conclusions

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.

Factors affecting tuberculosis strain success over 10 years in a high TB- and HIV-burdened community

BACKGROUND

Factors associated with Mycobacterium tuberculosis (Mtb) strain success over time in high burdened communities are unknown.

METHODS

Mtb isolates collected over 10 years from sputum-positive tuberculosis (TB) patients resident in the study site underwent IS6110-based restriction fragment length polymorphism analysis. Clinical, demographic and social data were extracted from clinic records and interviewer-administered questionnaires. Strains were defined as persistently successful, transiently successful or unsuccessful based on the average number of cases per year and their continued presence over time.

RESULTS

Genotyping data were available on 789 TB cases. Of the 311 distinct Mtb strains (≥6 bands) identified, 247 were categorized as unsuccessful strains, 12 transiently successful and 10 persistently successful strains. Strain success was not associated with age, gender, antiretroviral use or social factors. Persistently successful strains were less likely to be drug-resistant compared with transiently successful strains [odds ratio (OR): 0.13; 95% confidence interval (CI): 0.04 - 0.5]. Persistently successful strains were positively associated with host HIV-infection compared with unsuccessful strains, but this finding was not robust in sensitivity analyses.

CONCLUSIONS

Pathogen characteristics appear to play a greater role in Mtb strain success compared with social or host factors. This study supports the need for further investigations into the role of pathogen characteristics in strain success.

Effect of household and community interventions on the burden of tuberculosis in southern Africa: the ZAMSTAR community-randomised trial

BACKGROUND

Southern Africa has had an unprecedented increase in the burden of tuberculosis, driven by the HIV epidemic. The Zambia, South Africa Tuberculosis and AIDS Reduction (ZAMSTAR) trial examined two public health interventions that aimed to reduce the burden of tuberculosis by facilitating either rapid sputum diagnosis or integrating tuberculosis and HIV services within the community.

METHODS

ZAMSTAR was a community-randomised trial done in Zambia and the Western Cape province of South Africa. Two interventions, community-level enhanced tuberculosis case-finding (ECF) and household level tuberculosis-HIV care, were implemented between Aug 1, 2006, and July 31, 2009, and assessed in a 2×2 factorial design between Jan 9, 2010, and Dec 6, 2010. All communities had a strengthened tuberculosis-HIV programme implemented in participating health-care centres. 24 communities, selected according to population size and tuberculosis notification rate, were randomly allocated to one of four study groups using a randomisation schedule stratified by country and baseline prevalence of tuberculous infection: group 1 strengthened tuberculosis-HIV programme at the clinic alone; group 2, clinic plus ECF; group 3, clinic plus household intervention; and group 4, clinic plus ECF and household interventions. The primary outcome was the prevalence of culture-confirmed pulmonary tuberculosis in adults (≥18 years), defined as Mycobacterium tuberculosis isolated from one respiratory sample, measured 4 years after the start of interventions in a survey of 4000 randomly selected adults in each community in 2010. The secondary outcome was the incidence of tuberculous infection, measured using tuberculin skin testing in a cohort of schoolchildren, a median of 4 years after a baseline survey done before the start of interventions. This trial is registered, number ISRCTN36729271.

FINDINGS

Prevalence of tuberculosis was evaluated in 64,463 individuals randomly selected from the 24 communities; 894 individuals had active tuberculosis. Averaging over the 24 communities, the geometric mean of tuberculosis prevalence was 832 per 100,000 population. The adjusted prevalence ratio for the comparison of ECF versus non-ECF intervention groups was 1·09 (95% CI 0·86-1·40) and of household versus non-household intervention groups was 0·82 (0·64-1·04). The incidence of tuberculous infection was measured in a cohort of 8809 children, followed up for a median of 4 years; the adjusted rate ratio for ECF versus non-ECF groups was 1·36 (95% CI 0·59-3·14) and for household versus non-household groups was 0·45 (0·20-1·05).

INTERPRETATION

Although neither intervention led to a statistically significant reduction in tuberculosis, two independent indicators of burden provide some evidence of a reduction in tuberculosis among communities receiving the household intervention. By contrast the ECF intervention had no effect on either outcome.

FUNDING

Bill & Melinda Gates Foundation.

Impact of the antiretroviral treatment program on the burden of hospitalization for culture-confirmed tuberculosis in South African children: a time-series analysis

BACKGROUND

The HIV epidemic increased the burden of tuberculosis (TB) in sub-Saharan Africa. We evaluated the impact that scaling-up of the public-funded antiretroviral treatment (ART) program had on incidence of hospitalization for culture-confirmed and overall-TB in HIV-infected and HIV-uninfected children from 2005 to 2009.

METHODS

The study was undertaken in Soweto, South Africa, where ART coverage of HIV-infected children increased from 43% in 2005 to 84% by 2009. Trends in incidence of hospitalization for clinically diagnosed and culture-confirmed TB in children 3 months to <15 years of age, identified through laboratory and electronic databases, were analyzed by comparing crude incidence and regression analysis.

RESULTS

The incidence (per 100,000) of culture-confirmed TB declined by 63.1% from 2005 (69.8) compared with 2009 (25.8; P < 0.0001). This included a 70.6% reduction between 2005 and 2009 among HIV-infected children (incidence: 1566.3 versus 460.7, respectively; P < 0.0001) and 41.3% decrease in HIV-uninfected children (18.7 versus 11.0, respectively; P = 0.0003). The month-by-month rate of decline of culture-confirmed TB was 2.3% in HIV-infected and 1.1% in HIV-uninfected children over the study period. The residual burden of TB remained 42-fold greater in HIV-infected children, 78% of whom were severely immune compromised, compared with HIV-uninfected children by 2009.

CONCLUSION

Increase in ART coverage was associated with significant decline in TB hospitalizations in HIV-infected children. This reduction may also in part have been due to reduced Mycobacterium tuberculosis transmission resulting from increased ART access among HIV-infected adults, which may have contributed to the reduction of culture-confirmed TB in HIV-uninfected children.

Antiretroviral therapy for prevention of HIV and tuberculosis: a promising intervention but not a panacea

The demonstration of the efficacy of antiretroviral therapy (ART) for HIV prevention in heterosexual HIV serodiscordant couples has resulted in the call for widespread implementation of "Treatment as Prevention" (TasP) to confront the challenge of continued transmission of HIV. In addition, evidence of the possible effect of use of ART on decreasing the incidence of tuberculosis (TB) in persons living with HIV has also contributed further enthusiasm. Mathematical modeling studies evaluating the potential impact of TasP on the trajectory of the HIV and TB epidemics have inspired discussions about a possible future without AIDS. We present the evidence regarding the effect of ART on the incidence of HIV and TB, benefits and risks associated with embracing TasP, and the need for multicomponent prevention strategies and for further research to generate empiric data on the effect of TasP on HIV and TB at a population level.

Measuring the degree of integrated tuberculosis and HIV service delivery in Cape Town, South Africa

To address the considerable tuberculosis (TB)/HIV co-infected population in Cape Town, a number of clinics have made an effort of varying degrees to integrate TB and HIV services. This article describes the development of a theory-based survey instrument designed to quantify the extent to which services were integrated in 33 clinics and presents the results of the survey. Using principal factor analysis, eight factors were extracted and used to make comparisons across three types of clinics: co-located TB and antiretroviral therapy (ART) services, clinics with TB services only and clinics with ART only. Clinics with co-located services scored highest on measures related to integrated TB/ART service delivery compared to clinics with single services, but within group variability was high indicating that co-location of TB and ART services is a necessary but insufficient condition for integrated service delivery. In addition, we found almost all clinics with only TB services in our sample had highly integrated pre-ART services, suggesting that integration of these services across a large number of clinics is feasible and acceptable to clinic staff. TB clinics with highly integrated pre-ART services appear to be efficient sites for introducing ART given that co-infected patients are already engaged in care, and may potentially facilitate earlier access to treatment and minimize loss to follow-up.

Altered ratio of IFN-γ/IL-10 in patients with drug resistant Mycobacterium tuberculosis and HIV- Tuberculosis Immune Reconstitution Inflammatory Syndrome

We have described a clinical relationship between HIV-Tuberculosis Immune Reconstitution Inflammatory Syndrome (TB-IRIS) and anti-tubercular drug resistance. Here we studied the immune response of TB-IRIS patients from whom a drug-resistant (n = 11) or drug-susceptible (n = 25) Mycobacterium tuberculosis (MTB) strain was isolated after presenting with TB-IRIS. ELISpot analysis and multiplex cytokine analysis of the supernatant collected from peripheral blood mononuclear cells stimulated overnight with the heat-killed H37Rv MTB laboratory strain was used. Although there was no statistical difference in IFN-gamma ELISpot responses between the two groups, the results point towards higher bacterial load in the drug-resistant patients, possibly due to failed therapy. The ratio between secreted IFN-gamma/IL-10 and IL-2/IL-10 was significantly lower in TB-IRIS patients in whom the cause of TB was a drug-resistant strain compared to those with a fully sensitive strain (p = 0.02). Since host immune responses are dependent on the bacterial load, we hypothesise that the impaired cytokine balance is likely to be caused by the poorly controlled bacterial growth in these patients.

Retreatment tuberculosis in a South African community: the role of re-infection, HIV and antiretroviral treatment

BACKGROUND

Limited data exist on the impact of human immunodeficiency virus (HIV) or antiretroviral treatment (ART) on retreatment tuberculosis (TB).

METHODS

Retreatment TB episodes between 2001 and 2010 in a high HIV and TB burden community were linked to first-episode treatment outcomes, HIV status and ART use. Genotypic analysis of Mycobacterium tuberculosis isolates distinguished re-infection from reactivation TB.

RESULTS

A total of 2027 TB episodes occurred in 1755 adults: 564 were retreatment cases. New patients who interrupted or failed initial treatment, were HIV-positive or were not on ART more frequently developed retreatment TB (respectively P < 0.001, P = 0.01 and P = 0.02). Time intervals between successive diagnoses were shorter in patients who interrupted/failed treatment compared to those with favourable initial treatment outcomes (P < 0.001), but did not vary by HIV status or ART use. Genotypic data were available for 40 successive diagnoses, of which 19 had matching M. tuberculosis strains. Matching strains were associated with HIV-negative status (P < 0.001), treatment interruption/failure (P = 0.04) and shorter intervals between diagnoses (P = 0.02). HIV-positive patients and patients on ART were more likely to have non-matched strains (P = 0.01 and P = 0.03).

CONCLUSION

Among HIV-negative patients, retreatment TB was predominantly due to reactivation following poor initial treatment outcomes. In HIV-positive patients re-infection TB was more common, particularly among those on ART.

Assessment at antiretroviral clinics during TB treatment reduces loss to follow-up among HIV-infected patients

SETTING

A South African township clinic where loss to follow-up during TB treatment may prevent HIV-infected TB patients from receiving life-saving ART.

OBJECTIVE

To determine factors associated with loss to follow-up during TB treatment.

DESIGN

Regression analyses of a cohort of ART-eligible TB patients who commenced TB treatment and were followed for 24 weeks.

RESULTS

Of 111 ART-eligible TB patients, 15 (14%) died in the ensuing 24 weeks. Of the remaining 96 TB patients, 11 (11%) were lost to follow-up. All TB patients lost to follow-up did not initiate ART. Of 85 TB patients in follow-up, 62 (73%) initiated ART 56 days after TB diagnosis (median, IQR 33-77 days) and 31 days after initial assessment at an ART clinic (median, IQR: 18-55 days). The median duration from TB diagnosis to initial assessment at an ART clinic was 19 days (IQR: 7-48 days). At 24 weeks, 6 of 85 (7%) TB patients who presented to an ART clinic for assessment were lost to follow-up, compared to 5 of 11 (45%) TB patients who did not present to an ART clinic for assessment. Logistic regression analysis (adjusted odds ratio = 0.1, 95% confidence interval [95% CI]: 0.03-0.66) and our Cox proportional hazards model (hazard ratio = 0.2, 95% CI: 0.04-0.68) confirmed that assessment at an ART clinic during TB treatment reduced loss to follow-up.

CONCLUSION

Assessment at antiretroviral clinics for HIV care by trained health-care providers reduces loss to follow-up among HIV-infected patients with TB.

Scaling up interventions to achieve global tuberculosis control: progress and new developments

Tuberculosis is still one of the most important causes of death worldwide. The 2010 Lancet tuberculosis series provided a comprehensive overview of global control efforts and challenges. In this update we review recent progress. With improved control efforts, the world and most regions are on track to achieve the Millennium Development Goal of decreasing tuberculosis incidence by 2015, and the Stop TB Partnership target of halving 1990 mortality rates by 2015; the exception is Africa. Despite these advances, full scale-up of tuberculosis and HIV collaborative activities remains challenging and emerging drug-resistant tuberculosis is a major threat. Recognition of the effect that non-communicable diseases--such as smoking-related lung disease, diet-related diabetes mellitus, and alcohol and drug misuse--have on individual vulnerability, as well as the contribution of poor living conditions to community vulnerability, shows the need for multidisciplinary approaches. Several new diagnostic tests are being introduced in endemic countries and for the first time in 40 years a coordinated portfolio of promising new tuberculosis drugs exists. However, none of these advances offer easy solutions. Achievement of international tuberculosis control targets and maintenance of these gains needs optimum national health policies and services, with ongoing investment into new approaches and strategies. Despite growing funding in recent years, a serious shortfall persists. International and national financial uncertainty places gains at serious risk. Perseverance and renewed commitment are needed to achieve global control of tuberculosis, and ultimately, its elimination.

Antiretroviral outcomes in South African prisoners: a retrospective cohort analysis

BACKGROUND AND METHODS

Little is known about antiretroviral therapy (ART) outcomes in prisoners in Africa. We conducted a retrospective review of outcomes of a large cohort of prisoners referred to a public sector, urban HIV clinic. The review included baseline characteristics, sequential CD4 cell counts and viral load results, complications and co-morbidities, mortality and loss to follow-up up to 96 weeks on ART.

FINDINGS

148 inmates (133 male) initiated on ART were included in the study. By week 96 on ART, 73% of all inmates enrolled in the study and 92% of those still accessing care had an undetectable viral load (<400 copies/ml). The median CD4 cell count increased from 122 cells/mm(3) at baseline to 356 cells/mm(3) by 96 weeks. By study end, 96 (65%) inmates had ever received tuberculosis (TB) therapy with 63 (43%) receiving therapy during the study: 28% had a history of TB prior to ART initiation, 33% were on TB therapy at ART initiation and 22% developed TB whilst on ART. Nine (6%) inmates died, 7 in the second year on ART. Loss to follow-up (LTF) was common: 14 (9%) patients were LTF whilst still incarcerated, 11 (7%) were LTF post-release and 9 (6%) whose movements could not be traced. 16 (11%) inmates had inter-correctional facility transfers and 34 (23%) were released of whom only 23 (68%) returned to the ART clinic for ongoing follow-up.

CONCLUSIONS

Inmates responded well to ART, despite a high frequency of TB/HIV co-infection. Attention should be directed towards ensuring eligible prisoners access ART programs promptly and that inter-facility transfers and release procedures facilitate continuity of care. Institutional TB control measures should remain a priority.

Lipoarabinomannan in urine during tuberculosis treatment: association with host and pathogen factors and mycobacteriuria

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

HIV and tuberculosis--science and implementation to turn the tide and reduce deaths

INTRODUCTION

Every year, HIV-associated tuberculosis (TB) deprives 350,000 mainly young people of productive and healthy lives.People die because TB is not diagnosed and treated in those with known HIV infection and HIV infection is not diagnosed in those with TB. Even in those in whom both HIV and TB are diagnosed and treated, this often happens far too late. These deficiencies can be addressed through the application of new scientific evidence and diagnostic tools.

DISCUSSION

A strategy of starting antiretroviral therapy (ART) early in the course of HIV infection has the potential to considerably reduce both individual and community burden of TB and needs urgent evaluation for efficacy, feasibility and broader social and economic impact. Isoniazid preventive therapy can reduce the risk of TB and, if given strategically in addition to ART, provides synergistic benefit. Intensified TB screening as part of the "Three I's" strategy should be conducted at every clinic, home or community-based attendance using a symptoms-based algorithm, and new diagnostic tools should increasingly be used to confirm or refute TB diagnoses. Until such time when more sensitive and specific TB diagnostic assays are widely available, bolder approaches such as empirical anti-TB treatment need to be considered and evaluated. Patients with suspected or diagnosed TB must be screened for HIV and given cotrimoxazole preventive therapy and ART if HIV-positive. Three large randomized trials provide conclusive evidence that ART initiated within two to four weeks of start of anti-TB treatment saves lives, particularly in those with severe immunosuppression. The key to ensuring that these collaborative activities are delivered is the co-location and integration of TB and HIV services within the health system and the community.

CONCLUSIONS

Progress towards reducing HIV-associated TB deaths can be achieved through attention to simple and deliverable actions on the ground.

Antiretroviral therapy for prevention of tuberculosis in adults with HIV: a systematic review and meta-analysis

BACKGROUND

Human immunodeficiency virus (HIV) infection is the strongest risk factor for developing tuberculosis and has fuelled its resurgence, especially in sub-Saharan Africa. In 2010, there were an estimated 1.1 million incident cases of tuberculosis among the 34 million people living with HIV worldwide. Antiretroviral therapy has substantial potential to prevent HIV-associated tuberculosis. We conducted a systematic review of studies that analysed the impact of antiretroviral therapy on the incidence of tuberculosis in adults with HIV infection.

METHODS AND FINDINGS

PubMed, Embase, African Index Medicus, LILACS, and clinical trial registries were systematically searched. Randomised controlled trials, prospective cohort studies, and retrospective cohort studies were included if they compared tuberculosis incidence by antiretroviral therapy status in HIV-infected adults for a median of over 6 mo in developing countries. For the meta-analyses there were four categories based on CD4 counts at antiretroviral therapy initiation: (1) less than 200 cells/µl, (2) 200 to 350 cells/µl, (3) greater than 350 cells/µl, and (4) any CD4 count. Eleven studies met the inclusion criteria. Antiretroviral therapy is strongly associated with a reduction in the incidence of tuberculosis in all baseline CD4 count categories: (1) less than 200 cells/µl (hazard ratio [HR] 0.16, 95% confidence interval [CI] 0.07 to 0.36), (2) 200 to 350 cells/µl (HR 0.34, 95% CI 0.19 to 0.60), (3) greater than 350 cells/µl (HR 0.43, 95% CI 0.30 to 0.63), and (4) any CD4 count (HR 0.35, 95% CI 0.28 to 0.44). There was no evidence of hazard ratio modification with respect to baseline CD4 count category (p = 0.20).

CONCLUSIONS

Antiretroviral therapy is strongly associated with a reduction in the incidence of tuberculosis across all CD4 count strata. Earlier initiation of antiretroviral therapy may be a key component of global and national strategies to control the HIV-associated tuberculosis syndemic.

REVIEW REGISTRATION

International Prospective Register of Systematic Reviews CRD42011001209 Please see later in the article for the Editors' Summary.

HIV treatment as prevention: natural experiments highlight limits of antiretroviral treatment as HIV prevention

There is growing enthusiasm for increasing coverage of antiretroviral treatment among HIV-infected people for the purposes of preventing ongoing transmission. Treatment as prevention will face a number of barriers when implemented in real world populations, which will likely lead to the effectiveness of this strategy being lower than proposed by optimistic modelling scenarios or ideal clinical trial settings. Some settings, as part of their prevention and treatment strategies, have already attained rates of HIV testing and use of antiretroviral therapy--with high levels of viral suppression--that many countries would aspire to as targets for a treatment-as-prevention strategy. This review examines a number of these "natural experiments", namely, British Columbia, San Francisco, France, and Australia, to provide commentary on whether treatment as prevention has worked in real world populations. This review suggests that the population-level impact of this strategy is likely to be considerably less than as inferred from ideal conditions.

High prevalence of self-reported undiagnosed HIV despite high coverage of HIV testing: a cross-sectional population based sero-survey in South Africa

Objectives

To measure HIV prevalence and uptake of HIV counseling and testing (HCT) in a peri-urban South African community. To assess predictors for previous HIV testing and the association between the yield of previously undiagnosed HIV and time of last negative HIV test

Methods

A random sample of 10% of the adult population (≥15 years) were invited to attend a mobile HCT service. Study procedures included a questionnaire, HIV testing and CD4 counts. Predictors for previous testing were determined using a binominal model.

Results

1,144 (88.0%) of 1,300 randomly selected individuals participated in the study. 71.0% (68.3–73.6) had previously had an HIV test and 37.5% (34.6–40.5) had tested in the past 12 months. Men, migrants and older (>35 years) and younger (<20 years) individuals were less likely to have had a previous HIV test. Overall HIV prevalence was 22.7 (20.3–25.3) with peak prevalence of 41.8% (35.8–47.8) in women aged 25.1–35 years and 37.5% (26.7–48.3) in men aged 25.1–45 years. Prevalence of previously undiagnosed HIV was 10.3% (8.5–12.1) overall and 4.5% (2.3–6.6), 8.0% (CI 3.9–12.0) and 20.0% (13.2–26.8) in individuals who had their most recent HIV test within 1, 1–2 and more than 2 years prior to the survey.

Conclusion

The high burden of undiagnosed HIV in individuals who had recently tested underscores the importance of frequent repeat testing at least annually. The high prevalence of previously undiagnosed HIV in individuals reporting a negative test in the 12 months preceding the survey indicates a very high incidence. Innovative prevention strategies are needed.

Harnessing the prevention benefits of antiretroviral therapy to address HIV and tuberculosis

After 30 years we are still struggling to address a devastating HIV pandemic in which over 25 million people have died. In 2010, an estimated 34 million people were living with HIV, around 70% of whom live in sub-Saharan Africa. Furthermore, in 2009 there were an estimated 1.2 million new HIV-associated TB cases, and tuberculosis (TB) accounted for 24% of HIV-related deaths. By the end of 2010, 6.6 million people were taking antiretroviral therapy (ART), around 42% of those in need as defined by the 2010 World Health Organization (WHO) guidelines. Despite this achievement, around 9 million people were eligible and still in need of treatment, and new infections (approximately 2.6 million in 2010 alone) continue to add to the future caseload. This combined with the international fiscal crisis has led to a growing concern regarding weakening of the international commitment to universal access and delivery of the Millennium Development Goals by 2015. The recently launched UNAIDS/WHO Treatment 2.0 platform calls for accelerated simplification of ART, in line with a public health approach, to achieve and sustain universal access to ART, including maximizing the HIV and TB preventive benefit of ART by treating people earlier, in line with WHO 2010 normative guidance. The potential individual and public health prevention benefits of using treatment in the prevention of HIV and TB enhance the value of the universal access pledge from a life-saving initiative, to a strategic investment aimed at ending the HIV epidemic. This review analyzes the gaps and summarizes the evidence regarding ART in the prevention of HIV and TB.

Towards an improved investment approach for an effective response to HIV/AIDS

Substantial changes are needed to achieve a more targeted and strategic approach to investment in the response to the HIV/AIDS epidemic that will yield long-term dividends. Until now, advocacy for resources has been done on the basis of a commodity approach that encouraged scaling up of numerous strategies in parallel, irrespective of their relative effects. We propose a strategic investment framework that is intended to support better management of national and international HIV/AIDS responses than exists with the present system. Our framework incorporates major efficiency gains through community mobilisation, synergies between programme elements, and benefits of the extension of antiretroviral therapy for prevention of HIV transmission. It proposes three categories of investment, consisting of six basic programmatic activities, interventions that create an enabling environment to achieve maximum effectiveness, and programmatic efforts in other health and development sectors related to HIV/AIDS. The yearly cost of achievement of universal access to HIV prevention, treatment, care, and support by 2015 is estimated at no less than US$22 billion. Implementation of the new investment framework would avert 12·2 million new HIV infections and 7·4 million deaths from AIDS between 2011 and 2020 compared with continuation of present approaches, and result in 29·4 million life-years gained. The framework is cost effective at $1060 per life-year gained, and the additional investment proposed would be largely offset from savings in treatment costs alone.

Force of tuberculosis infection among adolescents in a high HIV and TB prevalence community: a cross-sectional observation study

Background

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.

Methods

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.

Results

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.

Conclusions

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.