Optimizing the cascade of prevention to protect people from tuberculosis: A potential game changer for reducing global tuberculosis incidence.

The provision of tuberculosis preventive treatment is one of the critical interventions to reduce tuberculosis incidence and ultimately eliminate the disease, yet we still miss appropriate tools for an impactful intervention and treatment coverage remains low. We used recent data, epidemiological estimates, and research findings to analyze the challenges of each step of the cascade of tuberculosis prevention that currently delay the strategy implementation. We addressed research gaps and implementation bottlenecks that withhold key actions in tuberculosis case finding, testing for tuberculosis infection, provision of preventive treatment with safer, shorter regimens and supporting people to complete their treatment. Empowering communities to generate demand for preventive therapy and other prevention services in a holistic manner and providing adequate financial support to sustain implementation are essential requirements. The adoption of an effective, universal monitoring and evaluation system is a prerequisite to provide general and granular insight, and to steer progress of the tuberculosis infection strategy at global and local level.

PASS to End TB in Europe: Accelerated efforts on prevention and systematic screening to end tuberculosis in the WHO European Region by 2030.

OBJECTIVES: Outline the objectives, methods, and initial stages of the Prevention and Systematic Screening (PASS) initiative, a complimentary element of the innovative new approach of technical assistance mechanisms of WHO and its partners to countries aligned to the Regional TB Action Plan to End TB in the European Region by 2030. DESIGN: To provide an objective and critical overview of the existing landscape on TB epidemic in the WHO European Region (the European Region) and ii) identify the strategic significance of proactive measures aimed at approaching TB pre-elimination in the Region. RESULTS: Interventions primarily include systematic screening for TB disease and treatment for TB infection (TBI). CONCLUSIONS: PASS to End TB is an exemplary initiative of how technical and funding partners are joining hands to support national health programmes to work towards global commitments to curb major public health challenges like TB.

Tuberculosis treatment monitoring tests during routine practice: study design guidance.

SCOPE: The current tools for tuberculosis (TB) treatment monitoring, smear microscopy and culture, cannot accurately predict poor treatment outcomes. Research into new TB treatment monitoring tools (TMTs) is growing, but data are unreliable. In this article, we aim to provide guidance for studies investigating and evaluating TB TMT for use during routine clinical care. Here, a TB TMT would guide treatment during the course of therapy, rather than testing for a cure at the regimen's end. This article does not cover the use of TB TMTs as surrogate endpoints in the clinical trial context. METHODS: Guidelines were initially informed by experiences during a systematic review of TB TMTs. Subsequently, a small content expert group was consulted for feedback on initial recommendations. After revision, feedback from substantive experts across sectors was sought. QUESTIONS ADDRESSED BY THE GUIDELINE AND RECOMMENDATIONS: The proposed considerations and recommendations for studies evaluating TB TMTs for use during the treatment in routine clinical care fall into eight domains. We provide specific recommendations regarding study design and recruitment, outcome definitions, reference standards, participant follow-up, clinical setting, study population, treatment regimen reporting, and index tests and data presentation. Overall, TB TMTs should be evaluated in a manner similar to diagnostic tests, but TB TMT accuracy must be assessed at multiple timepoints throughout the treatment course, and TB TMTs should be evaluated in study populations who have already received a diagnosis of TB. Study design and outcome definitions must be aligned with the developmental phase of the TB TMT under evaluation. There is no reference standard for TB treatment response, so different reference standards and comparator tests have been proposed, the selection of which will vary depending on the developmental phase of the TMT under assessment. The use of comparator tests can assist in generating evidence. Clarity is required when reporting of timepoints, TMT read-outs, and analysis results. Implementing these recommendations will lead to higher quality TB TMT studies that will allow data to be meaningfully compared, thereby facilitating the development of novel tools to guide individual TB therapy and improve treatment outcomes.

Target product profiles: tests for tuberculosis treatment monitoring and optimization.

The World Health Organization has developed target product profiles containing minimum and optimum targets for key characteristics for tests for tuberculosis treatment monitoring and optimization. Tuberculosis treatment optimization refers to initiating or switching to an effective tuberculosis treatment regimen that results in a high likelihood of a good treatment outcome. The target product profiles also cover tests of cure conducted at the end of treatment. The development of the target product profiles was informed by a stakeholder survey, a cost-effectiveness analysis and a patient-care pathway analysis. Additional feedback from stakeholders was obtained by means of a Delphi-like process, a technical consultation and a call for public comment on a draft document. A scientific development group agreed on the final targets in a consensus meeting. For characteristics rated of highest importance, the document lists: (i) high diagnostic accuracy (sensitivity and specificity); (ii) time to result of optimally ≤ 2 hours and no more than 1 day; (iii) required sample type to be minimally invasive, easily obtainable, such as urine, breath, or capillary blood, or a respiratory sample that goes beyond sputum; (iv) ideally the test could be placed at a peripheral-level health facility without a laboratory; and (v) the test should be affordable to low- and middle-income countries, and allow wide and equitable access and scale-up. Use of these target product profiles should facilitate the development of new tuberculosis treatment monitoring and optimization tests that are accurate and accessible for all people being treated for tuberculosis.

L'Organisation mondiale de la santé a élaboré des profils de produits cibles contenant des cibles minimales et optimales pour les caractéristiques principales des essais destinés au suivi et à l'optimisation du traitement de la tuberculose. L'optimisation du traitement de la tuberculose fait référence à l'instauration d'un régime de traitement efficace de la tuberculose ou à l'adoption d'un tel régime, avec une probabilité élevée d'obtenir de bons résultats thérapeutiques. Les profils de produits cibles couvrent également les essais de guérison effectués à l'issue du traitement. Les profils de produits cibles ont été élaborés sur la base d'un sondage auprès des parties prenantes, d'une analyse coût-efficacité et d'une analyse du parcours de soins du patient. Des retours supplémentaires des parties prenantes ont été obtenus au moyen d'un processus créé selon la méthode Delphi, d'une consultation technique et d'un appel à commentaires publics sur un projet de document. Un groupe d'élaboration scientifique s'est mis d'accord sur les objectifs finaux lors d'une réunion de concertation. En ce qui concerne les caractéristiques jugées les plus importantes, le document énumère ce qui suit: (i) une grande précision diagnostique (sensibilité et spécificité); (ii) un délai idéal d'obtention des résultats ≤ 2 heures et au maximum de 1 jour; (iii) le type d'échantillon requis doit être peu invasif et facile à obtenir, comme l'urine, l'haleine ou le sang capillaire, ou bien un échantillon respiratoire au-delà des expectorations; (iv) idéalement, l'essai pourrait avoir lieu dans un établissement de santé périphérique sans laboratoire ; et (v) l'essai devrait être abordable pour les pays à revenu faible et intermédiaire et permettre un accès large et équitable ainsi qu'une mise à l'échelle. L'utilisation de ces profils de produits cibles devrait faciliter la mise au point de nouveaux essais de surveillance et d'optimisation du traitement de la tuberculose qui soient précis et accessibles à toutes les personnes suivant un traitement pour la tuberculose.

La Organización Mundial de la Salud ha elaborado perfiles de productos objetivo que contienen objetivos mínimos y óptimos para las características principales de las pruebas de seguimiento y optimización del tratamiento de la tuberculosis. La optimización del tratamiento de la tuberculosis consiste en iniciar o cambiar a un régimen eficaz de tratamiento de la tuberculosis que ofrezca una alta probabilidad de un buen resultado terapéutico. Los perfiles de productos objetivo también abarcan las pruebas de curación realizadas al final del tratamiento. La elaboración de los perfiles de los productos objetivo se basó en una encuesta a las partes interesadas, un análisis de rentabilidad y un análisis de la vía de atención al paciente. Se obtuvo información adicional de las partes interesadas mediante un proceso tipo Delphi, una consulta técnica y una convocatoria de comentarios públicos sobre un borrador del documento. Un grupo de desarrollo científico acordó los objetivos finales en una reunión de consenso. Para las características clasificadas de mayor importancia, el documento enumera: (i) alta precisión diagnóstica (sensibilidad y especificidad); (ii) tiempo hasta el resultado de óptimamente ≤ 2 horas y no más de 1 día; (iii) el tipo de muestra requerida debe ser mínimamente invasiva, fácil de obtener, como orina, aliento o sangre capilar, o una muestra respiratoria que vaya más allá del esputo; (iv) idealmente la prueba podría realizarse en un centro sanitario periférico sin laboratorio; y (v) la prueba debe ser asequible para los países de ingresos bajos y medios y permitir un acceso amplio y equitativo y su expansión. El uso de estos perfiles de producto objetivo debería facilitar el desarrollo de pruebas nuevas de seguimiento y optimización del tratamiento de la tuberculosis que sean precisas y accesibles para todas las personas que reciben tratamiento antituberculoso.

Economic evaluations of immunization programs as an indispensable tool for policymakers.

Introducing new vaccines within national immunization programs requires careful consideration of disease- and vaccine-related issues as well as of the strength of the program and the affected health system. Economic evaluations play an essential role in this process. In this editorial, we set the context and invite contributions for a BMC Health Services Research Collection of articles titled 'Economic Evaluations of Vaccine Programs'.

Scaling Up TB Screening and TB Preventive Treatment Globally: Key Actions and Healthcare Service Costs.

The 2018 United Nations High-Level Meeting on Tuberculosis (UNHLM) set targets for case detection and TB preventive treatment (TPT) by 2022. However, by the start of 2022, about 13.7 million TB patients still needed to be detected and treated, and 21.8 million household contacts needed to be given TPT globally. To inform future target setting, we examined how the 2018 UNHLM targets could have been achieved using WHO-recommended interventions for TB detection and TPT in 33 high-TB burden countries in the final year of the period covered by the UNHLM targets. We used OneHealth-TIME model outputs combined with the unit cost of interventions to derive the total costs of health services. Our model estimated that, in order to achieve UNHLM targets, >45 million people attending health facilities with symptoms would have needed to be evaluated for TB. An additional 23.1 million people with HIV, 19.4 million household TB contacts, and 303 million individuals from high-risk groups would have required systematic screening for TB. The estimated total costs amounted to ~USD 6.7 billion, of which ~15% was required for passive case finding, ~10% for screening people with HIV, ~4% for screening household contacts, ~65% for screening other risk groups, and ~6% for providing TPT to household contacts. Significant mobilization of additional domestic and international investments in TB healthcare services will be needed to reach such targets in the future.

A new online toolkit to support implementation research to enhance the use of digital innovations to End TB.

Digital technologies are playing an increasing role in the global response to tuberculosis (TB), however their effectiveness and impact are often shaped in the context in which they are implemented. Implementation research can help facilitate the effective introduction of digital health technologies in TB programmes. In 2020, the Implementation Research for Digital Technologies and TB online toolkit (IR4DTB) was developed and launched by the Special Programme for Research and Training in Tropical Diseases, and the Global TB Programme at the World Health Organization (WHO), to build local capacity for IR and promote the effective use of digital technologies within TB programmes. This paper describes the development and piloting of the IR4DTB toolkit, a self-learning tool designed for TB programme implementers. The toolkit comprises six modules reflecting key steps of the IR process, practical instructions and guidance on how to complete these steps, and real-word case studies to illustrate key learning points. This paper also describes the launch of the IR4DTB during a five-day training workshop with TB staff from China, Uzbekistan, Pakistan, Malaysia. The workshop included facilitated sessions on the IR4DTB modules, and provided an opportunity for participants to work with facilitators to develop a comprehensive IR proposal addressing an identified challenge related to the implementation and/or scale-up of digital health technologies for TB care in their home country. Post-workshop evaluation revealed high level of satisfaction among participants with the workshop content and format. The IR4DTB toolkit is a replicable model which can be used to strengthen the TB staff capacity to innovate within a culture of continuous collection of evidence. Through continued trainings and adaptation of the toolkit alongside the integration of digital technologies within TB prevention and care, this model has the potential to contribute directly to all components of the End TB Strategy.

Scaling up target regimens for tuberculosis preventive treatment in Brazil and South Africa: An analysis of costs and cost-effectiveness.

BACKGROUND: Shorter, safer, and cheaper tuberculosis (TB) preventive treatment (TPT) regimens will enhance uptake and effectiveness. WHO developed target product profiles describing minimum requirements and optimal targets for key attributes of novel TPT regimens. We performed a cost-effectiveness analysis addressing the scale-up of regimens meeting these criteria in Brazil, a setting with relatively low transmission and low HIV and rifampicin-resistant TB (RR-TB) prevalence, and South Africa, a setting with higher transmission and higher HIV and RR-TB prevalence. METHODS AND FINDINGS: We used outputs from a model simulating scale-up of TPT regimens meeting minimal and optimal criteria. We assumed that drug costs for minimal and optimal regimens were identical to 6 months of daily isoniazid (6H). The minimal regimen lasted 3 months, with 70% completion and 80% efficacy; the optimal regimen lasted 1 month, with 90% completion and 100% efficacy. Target groups were people living with HIV (PLHIV) on antiretroviral treatment and household contacts (HHCs) of identified TB patients. The status quo was 6H at 2019 coverage levels for PLHIV and HHCs. We projected TB cases and deaths, TB-associated disability-adjusted life years (DALYs), and costs (in 2020 US dollars) associated with TB from a TB services perspective from 2020 to 2035, with 3% annual discounting. We estimated the expected costs and outcomes of scaling up 6H, the minimal TPT regimen, or the optimal TPT regimen to reach all eligible PLHIV and HHCs by 2023, compared to the status quo. Maintaining current 6H coverage in Brazil (0% of HHCs and 30% of PLHIV treated) would be associated with 1.1 (95% uncertainty range [UR] 1.1-1.2) million TB cases, 123,000 (115,000-132,000) deaths, and 2.5 (2.1-3.1) million DALYs and would cost $1.1 ($1.0-$1.3) billion during 2020-2035. Expanding the 6H, minimal, or optimal regimen to 100% coverage among eligible groups would reduce DALYs by 0.5% (95% UR 1.2% reduction, 0.4% increase), 2.5% (1.8%-3.0%), and 9.0% (6.5%-11.0%), respectively, with additional costs of $107 ($95-$117) million and $51 ($41-$60) million and savings of $36 ($14-$58) million, respectively. Compared to the status quo, costs per DALY averted were $7,608 and $808 for scaling up the 6H and minimal regimens, respectively, while the optimal regimen was dominant (cost savings, reduced DALYs). In South Africa, maintaining current 6H coverage (0% of HHCs and 69% of PLHIV treated) would be associated with 3.6 (95% UR 3.0-4.3) million TB cases, 843,000 (598,000-1,201,000) deaths, and 36.7 (19.5-58.0) million DALYs and would cost $2.5 ($1.8-$3.6) billion. Expanding coverage with the 6H, minimal, or optimal regimen would reduce DALYs by 6.9% (95% UR 4.3%-95%), 15.5% (11.8%-18.9%), and 38.0% (32.7%-43.0%), respectively, with additional costs of $79 (-$7, $151) million and $40 (-$52, $140) million and savings of $608 ($443-$832) million, respectively. Compared to the status quo, estimated costs per DALY averted were $31 and $7 for scaling up the 6H and minimal regimens, while the optimal regimen was dominant. Study limitations included the focus on 2 countries, and no explicit consideration of costs incurred before the decision to prescribe TPT. CONCLUSIONS: Our findings suggest that scale-up of TPT regimens meeting minimum or optimal requirements would likely have important impacts on TB-associated outcomes and would likely be cost-effective or cost saving.

Prioritising attributes for tuberculosis preventive treatment regimens: a modelling analysis.

BACKGROUND: Recent years have seen important improvements in available preventive treatment regimens for tuberculosis (TB), and research is ongoing to develop these further. To assist with the formulation of target product profiles for future regimens, we examined which regimen properties would be most influential in the epidemiological impact of preventive treatment. METHODS: Following expert consultation, we identified 5 regimen properties relevant to the incidence-reducing impact of a future preventive treatment regimen: regimen duration, efficacy, ease-of-adherence (treatment completion rates in programmatic conditions), forgiveness to non-completion and the barrier to developing rifampicin resistance during treatment. For each regimen property, we elicited expert input for minimally acceptable and optimal (ideal-but-feasible) performance scenarios for future regimens. Using mathematical modelling, we then examined how each regimen property would influence the TB incidence reduction arising from full uptake of future regimens according to current WHO guidelines, in four countries: South Africa, Kenya, India and Brazil. RESULTS: Of all regimen properties, efficacy is the single most important predictor of epidemiological impact, while ease-of-adherence plays an important secondary role. These results are qualitatively consistent across country settings; sensitivity analyses show that these results are also qualitatively robust to a range of model assumptions, including the mechanism of action of future preventive regimens. CONCLUSIONS: As preventive treatment regimens against TB continue to improve, understanding the key drivers of epidemiological impact can assist in guiding further development. By meeting these key targets, future preventive treatment regimens could play a critical role in global efforts to end TB.

REPRINT OF: CLASSIFICATION OF DIABETES MELLITUS.

Executive Summary This document updates the 1999 World Health Organization (WHO) classification of diabetes. It prioritizes clinical care and guides health professionals in choosing appropriate treatments at the time of diabetes diagnosis, and provides practical guidance to clinicians in assigning a type of diabetes to individuals at the time of diagnosis. It is a compromise between clinical and aetiological classification because there remain gaps in knowledge of the aetiology and pathophysiology of diabetes. While acknowledging the progress that is being made towards a more precise categorization of diabetes subtypes, the aim of this document is to recommend a classification that is feasible to implement in different settings throughout the world. The revised classification is presented in Table 1. Unlike the previous classification, this classification does not recognize subtypes of type 1 diabetes and type 2 diabetes and includes new types of diabetes ("hybrid types of diabetes" and "unclassified diabetes").

Framework for the evaluation of new tests for tuberculosis infection.

The scale-up of tuberculosis (TB) preventive treatment (TPT) must be accelerated to achieve the targets set by the United Nations High-level Meeting on TB and the End TB Strategy. The scale-up of effective TPT is hampered by concerns about operational challenges to implement the existing tests for TB infection. New simpler tests could facilitate the scale-up of testing for TB infection. We present a framework for evaluation of new immunodiagnostic tests for the detection of TB infection, with an aim to facilitate their standardised evaluation and accelerate adoption into global and national policies and subsequent scale-up. The framework describes the principles to be considered when evaluating new tests for TB infection and provides guidance to manufacturers, researchers, regulators and other users on study designs, populations, reference standards, sample size calculation and data analysis and it is also aligned with the Global Strategy for TB Research and Innovation adopted by the World Health Assembly in 2020. In addition, we briefly describe technical issues that should be considered when evaluating new tests, including the safety for skin tests, costs incurred by patients and the health system, and operational characteristics.

Guidelines for multi-model comparisons of the impact of infectious disease interventions.

BACKGROUND: Despite the increasing popularity of multi-model comparison studies and their ability to inform policy recommendations, clear guidance on how to conduct multi-model comparisons is not available. Herein, we present guidelines to provide a structured approach to comparisons of multiple models of interventions against infectious diseases. The primary target audience for these guidelines are researchers carrying out model comparison studies and policy-makers using model comparison studies to inform policy decisions. METHODS: The consensus process used for the development of the guidelines included a systematic review of existing model comparison studies on effectiveness and cost-effectiveness of vaccination, a 2-day meeting and guideline development workshop during which mathematical modellers from different disease areas critically discussed and debated the guideline content and wording, and several rounds of comments on sequential versions of the guidelines by all authors. RESULTS: The guidelines provide principles for multi-model comparisons, with specific practice statements on what modellers should do for six domains. The guidelines provide explanation and elaboration of the principles and practice statements as well as some examples to illustrate these. The principles are (1) the policy and research question - the model comparison should address a relevant, clearly defined policy question; (2) model identification and selection - the identification and selection of models for inclusion in the model comparison should be transparent and minimise selection bias; (3) harmonisation - standardisation of input data and outputs should be determined by the research question and value of the effort needed for this step; (4) exploring variability - between- and within-model variability and uncertainty should be explored; (5) presenting and pooling results - results should be presented in an appropriate way to support decision-making; and (6) interpretation - results should be interpreted to inform the policy question. CONCLUSION: These guidelines should help researchers plan, conduct and report model comparisons of infectious diseases and related interventions in a systematic and structured manner for the purpose of supporting health policy decisions. Adherence to these guidelines will contribute to greater consistency and objectivity in the approach and methods used in multi-model comparisons, and as such improve the quality of modelled evidence for policy.

Ebola Virus Infection Associated with Transmission from Survivors.

Ebola virus (EBOV) can persist in immunologically protected body sites in survivors of Ebola virus disease, creating the potential to initiate new chains of transmission. From the outbreak in West Africa during 2014-2016, we identified 13 possible events of viral persistence-derived transmission of EBOV (VPDTe) and applied predefined criteria to classify transmission events based on the strength of evidence for VPDTe and source and route of transmission. For 8 events, a recipient case was identified; possible source cases were identified for 5 of these 8. For 5 events, a recipient case or chain of transmission could not be confidently determined. Five events met our criteria for sexual transmission (male-to-female). One VPDTe event led to at least 4 generations of cases; transmission was limited after the other events. VPDTe has increased the importance of Ebola survivor services and sustained surveillance and response capacity in regions with previously widespread transmission.

Incorporating health workers' perspectives into a WHO guideline on personal protective equipment developed during an Ebola virus disease outbreak.

Background: Ebola virus disease (EVD) health facility transmission can result in infection and death of health workers. The World Health Organization (WHO) supports countries in preparing for and responding to public health emergencies, which often require developing new guidance in short timelines with scarce evidence. The objective of this study was to understand frontline physicians' and nurses' perspectives about personal protective equipment (PPE) use during the 2014-2016 EVD outbreak in West Africa and to incorporate these findings into the development process of a WHO rapid advice guideline. Methods : We surveyed frontline physicians and nurses deployed to West Africa between March and September of 2014. Results: We developed the protocol, obtained ethics approval, delivered the survey, analysed the data and presented the findings as part of the evidence-to-decision tables at the expert panel meeting where the recommendations were formulated within eight weeks. Forty-four physicians and nurses responded to the survey. They generally felt at low or extremely low risk of virus transmission with all types of PPE used. Eye protection reduced the ability to provide care, mainly due to impaired visibility because of fogging. Heat and dehydration were a major issue for 76% of the participants using goggles and for 64% using a hood. Both gowns and coveralls were associated with significant heat stress and dehydration. Most participants (59%) were very confident that they were using PPE correctly. Conclusion : Our study demonstrated that it was possible to incorporate primary data on end-users' preferences into a rapid advice guideline for a public health emergency in difficult field conditions. Health workers perceived a balance between transmission protection and ability to care for patients effectively while wearing PPE. These findings were used by the guideline development expert panel to formulate WHO recommendations on PPE for frontline providers caring for EVD patients in outbreak conditions.

Empiric TB Treatment of Severely Ill Patients With HIV and Presumed Pulmonary TB Improves Survival.

RATIONALE: In 2007, World Health Organization (WHO) issued emergency recommendations on empiric treatment of sputum acid-fast bacillus smear-negative patients with possible tuberculosis (TB) in HIV-prevalent areas, and called for operational research to evaluate their effectiveness. We sought to determine if early, empiric TB treatment of possible TB patients with abnormal chest radiography or severe illness as suggested by the 2007 WHO guidelines, is associated with improved survival. METHODS: We prospectively enrolled consecutive HIV-seropositive inpatients at Mulago Hospital in Kampala, Uganda, from 2007 to 2011 with cough for ≥2 weeks. We retrospectively examined the effect of empiric TB treatment before discharge on 8-week survival among those with and without a WHO-defined "danger sign," including fever >39°C, tachycardia >120 beats per minute, or tachypnea >30 breaths per minute. We modeled the interaction between empiric TB treatment and danger signs, and their combined effect on 8-week survival, and adjusted for relevant covariates. RESULTS: Among 631 sputum smear-negative patients, 322 (51%) had danger signs. Cumulative 8-week survival of patients with danger signs was significantly higher with empiric TB treatment (80%) than without treatment (64%, P < 0.001). After adjusting for duration of cough and concurrent hypoxemia, patients with danger signs who received empiric TB treatment had a 44% reduction in 8-week mortality (risk ratio 0.56, 95% confidence interval: 0.34-0.91, P = 0.020). CONCLUSIONS: Empiric TB treatment of HIV-seropositive, smear-negative, presumed pulmonary TB patients with 1 or more danger signs is associated with improved 8-week survival. Enhanced implementation of the 2007 WHO empiric treatment recommendations should be encouraged whenever and wherever rapid and highly sensitive diagnostic tests for TB are unavailable.

Continuous isoniazid for the treatment of latent tuberculosis infection in people living with HIV.

OBJECTIVE: This systematic review was carried out to determine the effectiveness of continuous isoniazid (given for at least 36 months) for the treatment of latent tuberculosis infection (LTBI) in people living with HIV (PLHIV). METHODS: Six databases and HIV and tuberculosis (TB) conference abstract books were searched for randomized controlled trials that compared the effectiveness of continuous isoniazid with 6 months of isoniazid. Outcomes of interest were TB incidence, mortality, adverse events and risk of drug resistance. Data were pooled using fixed-effects meta-analysis. RESULTS: Three studies were included, from Botswana, South Africa and India. The risk of active TB was 38% lower among patients receiving continuous isoniazid compared with isoniazid regimen for 6 months [relative risk (RR) 0.62, 95% confidence interval (CI): 0.42-0.89; I = 0%], and 49% lower for those with a positive tuberculin skin test (TST) (RR 0.51, 95% CI: 0.30-0.86; I = 7%). Similarly, individuals with positive TST had a 50% lower chance of death (RR 0.50, 95% CI: 0.27-0.91; I = 3%). Two studies found no evidence of an increase in adverse events in the continuous isoniazid group, whereas a third study, that used a different definition for adverse events, found strong evidence of increase. There was no evidence of increased drug resistance when continuous isoniazid was given. CONCLUSION: For PLHIV in settings with high TB and HIV prevalence and transmission, continuous isoniazid for at least 36 months is beneficial and probably outweighs the risk of increased adverse events compared with an isoniazid regimen for 6 months.