Performance of spirometry assessment at TB diagnosis.

BACKGROUND: Spirometry is considered relevant for the diagnosis and monitoring of post-TB lung disease. However, spirometry is rarely done in newly diagnosed TB patients.METHODS: Newly diagnosed, microbiologically confirmed TB patients were recruited for the study. Spirometry was performed within 21 days of TB treatment initiation according to American Thoracic Society/European Respiratory Society guidelines. Spirometry analysis was done using Global Lung Initiative equations for standardisation.RESULTS: Of 1,430 eligible study participants, 24.7% (353/1,430) had no spirometry performed mainly due to contraindications and 23.0% (329/1,430) had invalid results; 52.3% (748/1,430) of participants had a valid result, 82.8% (619/748) of whom had abnormal spirometry. Of participants with abnormal spirometry, 70% (436/619) had low forced vital capacity (FVC), 6.1% (38/619) had a low ratio of forced expiratory volume in 1 sec (FEV1) to FVC, and 19.1% (118/619) had low FVC, as well as low FEV1/FVC ratio. Among those with abnormal spirometry, 26.3% (163/619) had severe lung impairment.CONCLUSIONS: In this population, a high proportion of not performed and invalid spirometry assessments was observed; this was addressed by removing tachycardia as a (relative) contraindication from the study guidance and retraining. The high proportion of patients with severe pulmonary impairment at the time of TB diagnosis suggests a huge morbidity burden and calls for further longitudinal studies on the relevance of spirometry in predicting chronic lung impairment after TB.

Caregiver willingness to give TPT to children living with drug-resistant TB patients.

BACKGROUND Pediatric household contacts (HHCs) of patients with multidrug-resistant TB (MDR-TB) are at high risk of infection and active disease. Evidence of caregiver willingness to give MDR-TB preventive therapy (TPT) to children is limited.METHODS This was a cross-sectional study of HHCs of patients with MDR-TB to assess caregiver willingness to give TPT to children aged <13 years.RESULTS Of 743 adult and adolescent HHCs, 299 reported caring for children aged <13 years of age. The median caregiver age was 35 years (IQR 27-48); 75% were women. Among caregivers, 89% were willing to give children MDR TPT. In unadjusted analyses, increased willingness was associated with TB-related knowledge (OR 5.1, 95% CI 2.3-11.3), belief that one can die of MDR-TB (OR 5.2, 95% CI 1.2-23.4), concern for MDR-TB transmission to child (OR 4.5, 95% CI 1.6-12.4), confidence in properly taking TPT (OR 4.5, 95% CI 1.6-12.6), comfort telling family about TPT (OR 5.5, 95% CI 2.1-14.3), and willingness to take TPT oneself (OR 35.1, 95% CI 11.0-112.8).CONCLUSIONS A high percentage of caregivers living with MDR- or rifampicin-resistant TB patients were willing to give children a hypothetical MDR TPT. These results provide important evidence for the potential uptake of effective MDR TPT when implemented.

WHO target product profiles for TB preventive treatment.

BACKGROUND: The WHO has developed target product profiles (TPPs) describing the most appropriate qualities for future TPT regimens to assist developers in aligning the characteristics of new treatments with programmatic requirements.METHODS: A technical consultation group was convened by the WHO to determine regimen attributes with greatest potential impact for patients (i.e., improved risk/benefit profile) and populations (i.e., reduction in transmission and TB prevalence). The group categorised regimen attributes as 'priority´ or 'desirable´; and defined for each attribute the minimum requirements and optimal targets.RESULTS: Nine priority attributes were defined, including efficacy, treatment duration, safety, drug-drug interactions, barrier to emergence of drug resistance, target population, formulation, dosage, frequency and route of administration, stability and shelf life. Regimens meeting optimal targets were characterised, for example, as having superior efficacy, treatment duration of ≤2 weeks, and improved tolerability and safety profile compared with current regimens. The four desirable attributes included regimen cost, safety in special populations, treatment adherence and need for drug susceptibility testing in the index patient.DISCUSSION: It may be difficult for a single regimen to satisfy all characteristics so regimen developers may have to consider trade-offs. Additional operational aspects may be relevant to the feasibility and public health impact of new TPT regimens.

A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2.

SUMMARY: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles <10 µm that can remain suspended for hours before being inhaled. Because particulate filtering facepiece respirators ('respirators'; e.g. N95 masks) are more effective than surgical masks against bio-aerosols, many international organisations now recommend that health workers (HWs) wear a respirator when caring for individuals who may have COVID-19. In South Africa (SA), however, surgical masks are still recommended for the routine care of individuals with possible or confirmed COVID-19, with respirators reserved for so-called aerosol-generating procedures. In contrast, SA guidelines do recommend respirators for routine care of individuals with possible or confirmed tuberculosis (TB), which is also transmitted via aerosol. In health facilities in SA, distinguishing between TB and COVID-19 is challenging without examination and investigation, both of which may expose HWs to potentially infectious individuals. Symptom-based triage has limited utility in defining risk. Indeed, significant proportions of individuals with COVID-19 and/or pulmonary TB may not have symptoms and/or test negative. The prevalence of undiagnosed respiratory disease is therefore likely significant in many general clinical areas (e.g. waiting areas). Moreover, a proportion of HWs are HIV-positive and are at increased risk of severe COVID-19 and death. RECOMMENDATIONS: Sustained improvements in infection prevention and control (IPC) require reorganisation of systems to prioritise HW and patient safety. While this will take time, it is unacceptable to leave HWs exposed until such changes are made. We propose that the SA health system adopts a target of 'zero harm', aiming to eliminate transmission of respiratory pathogens to all individuals in every healthcare setting. Accordingly, we recommend: the use of respirators by all staff (clinical and non-clinical) during activities that involve contact or sharing air in indoor spaces with individuals who: (i) have not yet been clinically evaluated; or (ii) are thought or known to have TB and/or COVID-19 or other potentially harmful respiratory infections;the use of respirators that meet national and international manufacturing standards;evaluation of all respirators, at the least, by qualitative fit testing; andthe use of respirators as part of a 'package of care' in line with international IPC recommendations. We recognise that this will be challenging, not least due to global and national shortages of personal protective equipment (PPE). SA national policy around respiratory protective equipment enables a robust framework for manufacture and quality control and has been supported by local manufacturers and the Department of Trade, Industry and Competition. Respirator manufacturers should explore adaptations to improve comfort and reduce barriers to communication. Structural changes are needed urgently to improve the safety of health facilities: persistent advocacy and research around potential systems change remain essential.

Symptom and digital chest X-ray TB screening in South African prisons: yield and cost-effectiveness.

BACKGROUND: Correctional inmates are at a high risk of tuberculosis (TB). The optimal approach to screening this population is unclear.METHODS: We retrospectively reviewed records from TB screening in 64 correctional facilities in South Africa between January 2015 and July 2016. Inmates received symptom screening (any of cough, fever, weight loss, or night sweats) combined with digital chest X-ray (CXR), when available. CXRs were assessed as 'abnormal' or with no abnormalities. Inmates with either a symptom or an 'abnormal' CXR were asked to provide a single spot sputum for Xpert® MTB/RIF testing. We estimated the incremental cost-effectiveness ratio (ICER) per additional TB case detected using CXR screening among asymptomatic inmates.RESULTS: Of 61 580 inmates, CXR screening was available for 41 852. Of these, 19 711 (47.1%) had TB symptoms. Among 22 141 inmates without symptoms, 1939/19 783 (9.8%) had an abnormal CXR, and 8 (1.2%) were Xpert-positive among those with Xpert tests done. Of 14 942 who received symptom screening only and had symptoms, 84% (12 616) had an Xpert result, and 105 (0.8%) were positive. The ICER for CXR screening was US$22 278.CONCLUSION: Having CXR in addition to symptom screening increased yield but added considerable cost. A major limitation of screening was the low specificity of the symptom screen.

What causes symptoms suggestive of tuberculosis in HIV-positive people with negative initial investigations?

OBJECTIVE: To identify the causes of symptoms suggestive of tuberculosis (TB) among people living with the human immunodeficiency virus (PLHIV) in South Africa. METHODS: A consecutive sample of HIV clinic attendees with symptoms suggestive of TB (1 of cough, weight loss, fever or night sweats) at enrolment and at 3 months, and negative initial TB investigations, were systematically evaluated with standard protocols and diagnoses assigned using standard criteria. TB was 'confirmed' if Mycobacterium tuberculosis was identified within 6 months of enrolment, and 'clinical' if treatment started without microbiological confirmation. RESULTS: Among 103 participants, 50/103 were pre-antiretroviral therapy (ART) and 53/103 were on ART; respectively 68% vs. 79% were female; the median age was 35 vs. 45 years; the median CD4 count was 311 vs. 508 cells/mm³. Seventy-two (70%) had 5% measured weight loss and 50 (49%) had cough. The most common final diagnoses were weight loss due to severe food insecurity (n = 20, 19%), TB (n = 14, 14%: confirmed n = 7; clinical n = 7), other respiratory tract infection (n = 14, 14%) and post-TB lung disease (n = 9, 9%). The basis for TB diagnosis was imaging (n = 7), bacteriological confirmation from sputum (n = 4), histology, lumbar puncture and other (n = 1 each). CONCLUSION: PLHIV with persistent TB symptoms require further evaluation for TB using all available modalities, and for food insecurity in those with weight loss.

Lessons learnt conducting minimally invasive autopsies in private mortuaries as part of HIV and tuberculosis research in South Africa.

Current estimates of the burden of tuberculosis (TB) disease and cause-specific mortality in human immunodeficiency virus (HIV) positive people rely heavily on indirect methods that are less reliable for ascertaining individual-level causes of death and on mathematical models. Minimally invasive autopsy (MIA) is useful for diagnosing infectious diseases, provides a reasonable proxy for the gold standard in cause of death ascertainment (complete diagnostic autopsy) and, used routinely, could improve cause-specific mortality estimates. From our experience in performing MIAs in HIV-positive adults in private mortuaries in South Africa (during the Lesedi Kamoso Study), we describe the challenges we faced and make recommendations for the conduct of MIA in future studies or surveillance programmes, including strategies for effective communication, approaches to obtaining informed consent, risk management for staff and efficient preparation for the procedure.

Les estimations actuelles du poids de la tuberculose (TB) maladie et de la mortalité qui lui est due parmi les patients positifs à l'infection par le virus de l'immunodéficience humaine (VIH) dépendent beaucoup de méthodes indirectes, qui sont moins fiables pour vérifier les causes de décès au niveau individuel et de modèles mathématiques. Une autopsie peu invasive (MIA) est utile au diagnostic de maladies infectieuses, fournit une approximation raisonnable de l'étalon or de la vérification de la cause du décès c'est-à-dire une autopsie diagnostique complète. Si elle est utilisée en routine, elle pourrait améliorer les estimations de mortalité spécifique d'une cause. A partir de nos expériences de MIA sur des adultes positifs au VIH dans des morgues privées d'Afrique du Sud (au cours de l'étude Lesedi Kamoso), nous décrivons les défis rencontrés et faisons des recommandations pour la réalisation de MIA dans des études futures ou des programmes de surveillance, incluant des stratégies de communication efficaces, des approches visant à obtenir un consentement éclairé, une prise en charge du risque pour le personnel et une préparation efficace de la procédure.

Las estimaciones actuales de morbilidad por tuberculosis (TB) y de mortalidad por causas específicas en las personas positivas frente al virus de la inmunodeficiencia humana (VIH) se fundamentan en su mayor parte en métodos indirectos que son menos fiables para determinar las causas de muerte individuales y en modelizaciones matemáticas. La autopsia mínimamente invasiva (MIA) es útil en el diagnóstico de las enfermedades infecciosas, ofrece un sustituto aceptable al método de referencia para determinar la causa de muerte (que es la autopsia diagnóstica completa), y cuando se usa de manera sistemática, mejora las estimaciones de la mortalidad por causas específicas. A partir de su experiencia con la MIA en adultos con infección por el VIH en empresas fúnebres privadas en Suráfrica (durante el estudio Lesedi Kamoso), los autores describen las dificultades que encontraron y formulan recomendaciones que se pueden aplicar en el futuro al realizar la autopsia mínimamente invasiva en estudios de investigación o en programas de vigilancia; se preconizan estrategias de comunicación efectivas, métodos de obtención del consentimiento informado, la gestión de riesgos para el personal y la preparación eficiente del procedimiento.

Resource utilization for multidrug-resistant tuberculosis household contact investigations (A5300/I2003).

BACKGROUND: Current guidelines recommend evaluation of the household contacts (HHCs) of individuals with multidrug-resistant tuberculosis (MDR-TB); however, implementation of this policy is challenging. OBJECTIVE: To describe the resource utilization and operational challenges encountered when identifying and characterizing adult MDR-TB index cases and their HHCs. DESIGN: Cross-sectional study of adult MDR-TB index cases and HHCs at 16 clinical research sites in eight countries. Site-level resource utilization was assessed with surveys. RESULTS: Between October 2015 and April 2016, 308 index cases and 1018 HHCs were enrolled. Of 280 index cases with sputum collected, 94 were smear-positive (34%, 95%CI 28-39), and of 201 with chest X-rays, 87 had cavitary disease (43%, 95%CI 37-50) after a mean duration of treatment of 8 weeks. Staff required 512 attempts to evaluate the 308 households, with a median time per attempt of 4 h; 77% (95%CI 73-80) of HHCs were at increased risk for TB: 13% were aged <5 years, 8% were infected with the human immunodeficiency virus, and 79% were positive on the tuberculin skin test/interferon-gamma release assay. One hundred and twenty-one previously undiagnosed TB cases were identified. Issues identified by site staff included the complexity of personnel and participant transportation, infection control, personnel safety and management of stigma. CONCLUSION: HHC investigations can be high yield, but are labor-intensive.

An intervention to optimise the delivery of integrated tuberculosis and HIV services at primary care clinics: results of the MERGE cluster randomised trial.

OBJECTIVES: To evaluate the effect of an intervention to optimize TB/HIV integration on patient outcomes. METHODS: Cluster randomised control trial at 18 primary care clinics in South Africa. The intervention was placement of a nurse (TB/HIV integration officer) to facilitate provision of integrated TB/HIV services, and a lay health worker (TB screening officer) to facilitate TB screening for 24 months. Primary outcomes were i) incidence of hospitalisation/death among individuals newly diagnosed with HIV, ii) incidence of hospitalisation/death among individuals newly diagnosed with TB and iii) proportion of HIV-positive individuals newly diagnosed with TB who were retained in HIV care 12 months after enrolment. RESULTS: Of 3328 individuals enrolled, 3024 were in the HIV cohort, 731 in TB cohort and 427 in TB-HIV cohort. For the HIV cohort, the hospitalisation/death rate was 12.5 per 100 person-years (py) (182/1459py) in the intervention arm vs. 10.4/100py (147/1408 py) in the control arms respectively (Relative Risk (RR) 1.17 [95% CI 0.92-1.49]).For the TB cohort, hospitalisation/ death rate was 17.1/100 py (67/ 392py) vs. 11.1 /100py (32/289py) in intervention and control arms respectively (RR 1.37 [95% CI 0.78-2.43]). For the TB-HIV cohort, retention in care at 12 months was 63.0% (213/338) and 55.9% (143/256) in intervention and control arms (RR 1.11 [95% 0.89-1.38]). CONCLUSIONS: The intervention as implemented failed to improve patient outcomes beyond levels at control clinics. Effective strategies are needed to achieve better TB/HIV service integration and improve TB and HIV outcomes in primary care clinics. TRIAL REGISTRATION: South African Register of Clinical Trials (registration number DOH-27-1011-3846).

Evidence-informed policy making at country level: lessons learned from the South African Tuberculosis Think Tank.

BACKGROUND: National Tuberculosis Programmes (NTPs) require specialist input to support the development of policy and practice informed by evidence, typically against tight deadlines. OBJECTIVE: To describe lessons learned from establishing a dedicated tuberculosis (TB) think tank to advise the South African NTP on TB policy. INTERVENTION AND EVALUATION METHODS: A national TB think tank was established to advise the NTP in support of evidence-informed policy. Support was provided for activities, including meetings, modelling and regular telephone calls, with a wider network of unpaid expert advisers under an executive committee and working groups. Intervention evaluation used desktop analysis of documentary evidence, interviews and direct observation. RESULTS: The TB Think Tank evolved over time to acquire three key roles: an 'institution', a 'policy dialogue forum' and an 'interface'. Although enthusiasm was high, motivating participation among the NTP and external experts proved challenging. Motivation of working groups was most successful when aligned to a specific need for NTP decision making. Despite challenges, the TB Think Tank contributed to South Africa's first ever TB and human immunodeficiency virus (HIV) investment case, and the decision to create South Africa's first ever ring-fenced grant for TB. The TB Think Tank also assisted the NTP in formulating strategy to accelerate progress towards reaching World Health Organization targets. DISCUSSION: With partners, the TB Think Tank achieved major successes in supporting evidence-informed decision making, and garnered increased funding for TB in South Africa. Identifying ways to increase the involvement of NTP staff and other experts, and keeping the scope of the Think Tank well defined, could facilitate greater impact. Think tank initiatives could be replicated in other settings to support evidence-informed policy making.

Feasibility and acceptability of conducting HIV vaccine trials in adolescents in South Africa: Going beyond willingness to participate towards implementation.

BACKGROUND: HIV/AIDS remains a leading cause of death in adolescents (aged 15 - 25 years), and in sub-Saharan Africa HIV-related deaths continue to rise in this age group despite a decline in both adult and paediatric populations. This is attributable in part to high adolescent infection rates and supports the urgent need for more efficacious prevention strategies. In particular, an even partially effective HIV vaccine, given prior to sexual debut, is predicted to significantly curb adolescent infection rates. While adolescents have indicated willingness to participate in HIV vaccine trials, there are concerns around safety, uptake, adherence, and ethical and logistic issues. OBJECTIVES: To initiate a national, multisite project with the aim of identifying obstacles to conducting adolescent HIV vaccine trials in South Africa (SA). METHOD: A simulated HIV vaccine trial was conducted in adolescents aged 12 - 17 years across five SA research sites, using the already licensed Merck human papillomavirus vaccine Gardasil as a proxy for an HIV vaccine. Adolescents were recruited at community venues and, following a vaccine discussion group, invited to participate in the trial. Consent for trial enrolment was obtained from a parent or legal guardian, and participants aged 16 - 17 years were eligible only if sexually active. Typical vaccine trial procedures were applied during the five study visits, including the administration of vaccination injections at study visits 2, 3 and 4. RESULTS: The median age of participants was 14 years (interquartile range 13 - 15), with 81% between the ages of 12 and 15 years at enrolment. Overall, 98% of screened participants opted to receive the vaccine, 588 participants enrolled, and 524 (89%) attended the final visit. CONCLUSIONS: This trial showed that adolescents can be recruited, enrolled and retained in clinical prevention trials with parental support. While promising, these results were tempered by the coupling of sexual-risk eligibility criteria and the requirement for parental/guardian consent, which was probably a barrier to the enrolment of high-risk older adolescents. Further debate around appropriate consent approaches for such adolescents in HIV prevention studies is required.

HIV testing uptake among the household contacts of multidrug-resistant tuberculosis index cases in eight countries.

SETTING: The household contacts (HHCs) of multidrug-resistant tuberculosis (MDR-TB) index cases are at high risk of tuberculous infection and disease progression, particularly if infected with the human immunodeficiency virus (HIV). HIV testing is important for risk assessment and clinical management. METHODS: This was a cross-sectional, multi-country study of adult MDR-TB index cases and HHCs. All adult and child HHCs were offered HIV testing if never tested or if HIV-negative >1 year previously when last tested. We measured HIV testing uptake and used logistic regression to evaluate predictors. RESULTS: A total of 1007 HHCs of 284 index cases were enrolled in eight countries. HIV status was known at enrolment for 226 (22%) HHCs; 39 (4%) were HIV-positive. HIV testing was offered to 769 (98%) of the 781 remaining HHCs; 544 (71%) agreed to testing. Of 535 who were actually tested, 26 (5%) were HIV-infected. HIV testing uptake varied by site (median 86%, range 0-100%; P < 0.0001), and was lower in children aged <18 years than in adults (59% vs. 78%; adjusted for site P < 0.0001). CONCLUSIONS: HIV testing of HHCs of MDR-TB index cases is feasible and high-yield, with 5% testing positive. Reasons for low test uptake among children and at specific sites-including sites with high HIV prevalence-require further study to ensure all persons at risk for HIV are aware of their status.

Connectivity of diagnostic technologies: improving surveillance and accelerating tuberculosis elimination.

In regard to tuberculosis (TB) and other major global epidemics, the use of new diagnostic tests is increasing dramatically, including in resource-limited countries. Although there has never been as much digital information generated, this data source has not been exploited to its full potential. In this opinion paper, we discuss lessons learned from the global scale-up of these laboratory devices and the pathway to tapping the potential of laboratory-generated information in the field of TB by using connectivity. Responding to the demand for connectivity, innovative third-party players have proposed solutions that have been widely adopted by field users of the Xpert(®) MTB/RIF assay. The experience associated with the utilisation of these systems, which facilitate the monitoring of wide laboratory networks, stressed the need for a more global and comprehensive approach to diagnostic connectivity. In addition to facilitating the reporting of test results, the mobility of digital information allows the sharing of information generated in programme settings. When they become easily accessible, these data can be used to improve patient care, disease surveillance and drug discovery. They should therefore be considered as a public health good. We list several examples of concrete initiatives that should allow data sources to be combined to improve the understanding of the epidemic, support the operational response and, finally, accelerate TB elimination. With the many opportunities that the pooling of data associated with the TB epidemic can provide, pooling of this information at an international level has become an absolute priority.

Implementation and Operational Research: What Happens After a Negative Test for Tuberculosis? Evaluating Adherence to TB Diagnostic Algorithms in South African Primary Health Clinics.

INTRODUCTION AND BACKGROUND: Diagnostic tests for tuberculosis (TB) using sputum have suboptimal sensitivity among HIV-positive persons. We assessed health care worker adherence to TB diagnostic algorithms after negative sputum test results. METHODS: The XTEND (Xpert for TB-Evaluating a New Diagnostic) trial compared outcomes among people tested for TB in primary care clinics using Xpert MTB/RIF vs. smear microscopy as the initial test. We analyzed data from XTEND participants who were HIV positive or HIV status unknown, whose initial sputum Xpert MTB/RIF or microscopy result was negative. If chest radiography, sputum culture, or hospital referral took place, the algorithm for TB diagnosis was considered followed. Analysis of intervention (Xpert MTB/RIF) effect on algorithm adherence used methods for cluster-randomized trials with small number of clusters. RESULTS: Among 4037 XTEND participants with initial negative test results, 2155 (53%) reported being or testing HIV positive and 540 (14%) had unknown HIV status. Among 2155 HIV-positive participants [684 (32%) male, mean age 37 years (range, 18-79 years)], there was evidence of algorithm adherence among 515 (24%). Adherence was less likely among persons tested initially with Xpert MTB/RIF vs. smear [14% (142/1031) vs. 32% (364/1122), adjusted risk ratio 0.34 (95% CI: 0.17 to 0.65)] and for participants with unknown vs. positive HIV status [59/540 (11%) vs. 507/2155 (24%)]. CONCLUSIONS: We observed poorer adherence to TB diagnostic algorithms among HIV-positive persons tested initially with Xpert MTB/RIF vs. microscopy. Poor adherence to TB diagnostic algorithms and incomplete coverage of HIV testing represents a missed opportunity to diagnose TB and HIV, and may contribute to TB mortality.

Chronic hepatitis B increases mortality and complexity among HIV-coinfected patients in South Africa: a cohort study.

OBJECTIVES: To assess the effect of chronic hepatitis B on survival and clinical complexity among people living with HIV following antiretroviral therapy (ART) initiation. METHODS: We evaluated mortality and single-drug substitutions up to 3 years from ART initiation (median follow-up 2.75 years; interquartile range 2-3 years) among patients with and without chronic hepatitis B (CHB) enrolled in a workplace HIV care programme in South Africa. RESULTS: Mortality was increased for CHB patients with hepatitis B virus (HBV) DNA levels > 10 000 copies/mL (adjusted hazard ratio 3.1; 95% confidence interval 1.2-8.0) compared with non-CHB patients. We did not observe a similar difference between non-CHB patients and those with CHB and HBV DNA < 10 000 copies/mL (adjusted hazard ratio 0.70; 95% confidence interval 0.2-2.3). Single-drug substitutions occurred more frequently among coinfected patients regardless of HBV DNA level. CONCLUSIONS: Our findings suggest that CHB may increase mortality and complicate ART management.

Innovative clinical trial designs to rationalize TB vaccine development.

A recent trial of a leading tuberculosis (TB) vaccine candidate in 3000 South African infants failed to show protection over that from BCG alone, and highlights the difficulties in clinical development of TB vaccines. Progression of vaccine candidates to efficacy trials against TB disease rests on demonstration of safety and immunogenicity in target populations and protection against challenge in preclinical models, but immunologic correlates of protection are unknown, and animal models may not be predictive of results in humans. Even in populations most heavily affected by TB the sample sizes required for Phase 2b efficacy trials using TB disease as an endpoint are in the thousands. Novel clinical trial models have been developed to evaluate candidate TB vaccines in selected populations using biologically relevant outcomes and innovative statistical approaches. Such proof of concept studies can be used to more rationally select vaccine candidates for advancement to large scale trials against TB disease.

Impact of reduced hospitalisation on the cost of treatment for drug-resistant tuberculosis in South Africa.

SETTING: The cost of multidrug-resistant tuberculosis (MDR-TB) treatment is a major barrier to treatment scale-up in South Africa. OBJECTIVE: To estimate and compare the cost of treatment for rifampicin-resistant tuberculosis (RR-TB) in South Africa in different models of care in different settings. DESIGN: We estimated the costs of different models of care with varying levels of hospitalisation. These costs were used to calculate the total cost of treating all diagnosed cases of RR-TB in South Africa, and to estimate the budget impact of adopting a fully or partially decentralised model vs. a fully hospitalised model. RESULTS: The fully hospitalised model was 42% more costly than the fully decentralised model (US$13,432 vs. US$7753 per patient). A much shorter hospital stay in the decentralised models of care (44-57 days), compared to 128 days of hospitalisation in the fully hospitalised model, was the key contributor to the reduced cost of treatment. The annual total cost of treating all diagnosed cases ranged from US$110 million in the fully decentralised model to US$190 million in the fully hospitalised model. CONCLUSION: Following a more decentralised approach for treating RR-TB patients could potentially improve the affordability of RR-TB treatment in South Africa.

Accelerating progress towards tuberculosis elimination: the need for combination treatment and prevention.

Although estimated tuberculosis (TB) incidence is now falling globally, we are unlikely to achieve the Millennium Development Goal (MDG) TB targets without changing the emphasis of the global TB response in high human immunodeficiency virus prevalence settings. Two independent modelling exercises using South African data with different structures and assumptions conclude that, until new drugs, diagnostics and vaccines are available, a fully funded and accessible combination approach to anti-tuberculosis treatment and prevention, based on knowledge of local TB epidemiology and evidence-informed policy, is essential to accelerate progress towards zero new tuberculous infections, zero TB deaths and zero suffering from TB.

Pooling sputum from multiple individuals for Xpert® MTB/RIF testing: a strategy for screening high-risk populations.

SETTING: Symptom-based screening for tuberculosis (TB) disease is limited by poor performance of symptom screening in several key populations. We tested the hypothesis that pooling sputum from multiple individuals for Xpert(®) MTB/RIF testing would reduce the number of tests required while retaining an acceptable sensitivity, thus allowing the use of Xpert for TB screening. METHODS: We compared pooling ratios that would require the least number of assays using Xpert and determined that for a population with a TB prevalence of approximately 3%, a 1:5 pooling ratio is optimal. To evaluate sensitivity, we generated pools of one specimen with known Mycobacterium tuberculosis culture positivity (smear microscopy-positive or -negative) with four culture-negative specimens. RESULTS: All 20 of the pools generated from a smear- and culture-positive sputum sample were positive using Xpert. Of the 22 pools with a smear-negative, culture-positive sample, we included 17 in the analysis, of which 13 (76%) were Xpert-positive. CONCLUSIONS: Pooling of sputum samples using Xpert achieved reasonable sensitivity and warrants further evaluation of the systematic screening of high TB prevalence populations.