Household-Contact Investigation for Detection of Tuberculosis in Vietnam

Cachexia in tuberculosis in South-East Asian and African regions: knowledge gaps and untapped opportunities

Tuberculosis (TB) and cachexia are clinical entities that have a defined relationship, making them often found together. TB can lead to cachexia, while cachexia is a risk factor for TB. This article reviews cachexia in Tuberculosis patients in Southeast Asian and African regions by conducting a comprehensive literature search across electronic databases such as PubMed, Google Scholar, and Research Gate between 2013 and 2024 using keywords including 'Africa', 'cachexia', 'prevalence', 'implications', 'tuberculosis', and 'Southeast Asia. This article utilized only studies that satisfied the inclusion criteria, revealing knowledge gaps and untapped opportunities for cachexia in TB across Southeast Asian and African regions. Many Southeast Asian and Western Pacific patients initially receive a tuberculosis diagnosis. Sub-Saharan African countries are among the 30 high TB burden nations, according to the WHO. Food inadequacy and heightened energy expenditure can impair the immune system, leading to latent TB and subsequently, active infection. Symptoms needing attention: shortness of breath, productive cough, hyponatremia at 131 mmol/l, hypoalbuminemia at 2.1 g/dl, elevated aspartate transaminase at 75 U/l, increased lactate dehydrogenase at 654, and normocytic anemia. Comorbidities, such as kidney disease, cardiovascular disease, and asthma, can influence the nutritional status of individuals with TB. While efforts like screening, contact tracing, and utilizing gene Xpert to detect TB cases were implemented, only a few proved effective. It is essential to conduct further studies, including RCTs, in Southeast Asia and Africa to evaluate and manage cachexia in TB patients.

Community-Wide Active Case Finding for Tuberculosis: Time to Use the Evidence We Have

Tuberculosis, caused by the Mycobacterium tuberculosis (Mtb) bacteria, is one of the world's deadliest infectious diseases. Despite being the world's oldest pandemic, tuberculosis is very much a challenge of the modern era. In high-incidence settings, all people are at risk, irrespective of whether they have common vulnerabilities to the disease warranting the current WHO recommendations for community-wide tuberculosis active case finding in these settings. Despite good evidence of effectiveness in reducing tuberculosis transmission, uptake of this strategy has been lacking in the communities that would derive greatest benefit. We consider the various complexities in eliminating tuberculosis from the first principles of the disease, including diagnostic and other challenges that must be navigated under an elimination agenda. We make the case that community-wide tuberculosis active case finding is the best strategy currently available to drive elimination forward in high-incidence settings and that no time should be lost in its implementation. Recognizing that high-incidence communities vary in their epidemiology and spatiosocial characteristics, tuberculosis research and funding must now shift towards radically supporting local implementation and operational research in communities. This "preparing of the ground" for scaling up to community-wide intervention centers the local knowledge and local experience of community epidemiology to optimize implementation practices and accelerate reductions in community-level tuberculosis transmission.

Tuberculosis infection among close contacts of patients with pulmonary tuberculosis in China: a population-based, multicentered study

OBJECTIVES

Limited information is currently available on the prevalence of and risk factors for tuberculosis infection (TBI) among close contacts of patients with pulmonary TB (PTB) in China. In this study, we estimated the burden of TBI among close contacts using QuantiFERON-TB Gold In-Tube assay (QFT) and identified factors associated with TB transmission among this high-risk population.

METHODS

From January 1, 2018 to August 31, 2020, we identified laboratory-confirmed patients with PTB from a population-based, multicentered, cluster-randomized control trial for tuberculosis preventive treatment. Close contacts of these patients were identified, interviewed, and tested using the QFT assay. We estimated TBI prevalence and calculated ORs and 95% CIs for TBI risk factors.

RESULTS

A total of 3138 index cases and 8117 close contacts were identified. Of these contacts, 36 had PTB (a prevalence of 443.51 cases/100 000 population). Among the remaining 7986 close contacts; 3124 (39.12%) reported a positive QFT result. QFT positivity was significantly associated with older age (adjusted OR, 1.77; [95% CI, 1.27-2.47], 2.20; [95% CI, 1.59-3.05], and 2.74; [95% CI, 1.96-3.82]) for age groups: 35-44, 45-54, and 55-64, respectively) when compared with a younger age group: 5-14; longer contact duration (adjusted OR, 1.44; 95% CI, 1.22-1.69); and sharing of a bedroom (adjusted OR, 1.39; 95% CI, 1.18-1.65).

DISCUSSION

Our findings indicate a high TBI burden among the close contacts of PTB. The results also highlighted that contact tracing and investigation for TBI are necessary and beneficial, particularly for those who are older, have had a longer contact duration, and share a bedroom.

Community-Wide Universal HIV Test and Treat Intervention Reduces Tuberculosis Transmission in Rural Uganda: A Cluster-Randomized Trial

BACKGROUND

Human immunodeficiency virus (HIV) treatment reduces tuberculosis (TB) disease and mortality; however, the population-level impact of universal HIV-test-and-treat interventions on TB infection and transmission remain unclear.

METHODS

In a sub-study nested in the SEARCH trial, a community cluster-randomized trial (NCT01864603), we assessed whether a universal HIV-test-and-treat intervention reduced population-level incident TB infection in rural Uganda. Intervention communities received annual, population-level HIV testing and patient-centered linkage. Control communities received population-level HIV testing at baseline and endline. We compared estimated incident TB infection by arms, defined by tuberculin skin test conversion in a cohort of persons aged 5 and older, adjusting for participation and predictors of infection, and accounting for clustering.

RESULTS

Of the 32 trial communities, 9 were included, comprising 90 801 participants (43 127 intervention and 47 674 control). One-year cumulative incidence of TB infection was 16% in the intervention and 22% in the control; SEARCH reduced the population-level risk of incident TB infection by 27% (adjusted risk ratio = 0.73; 95% confidence interval [CI]: .57-.92, P = .005). In pre-specified analyses, the effect was largest among children aged 5-11 years and males.

CONCLUSIONS

A universal HIV-test-and-treat intervention reduced incident TB infection, a marker of population-level TB transmission. Investments in community-level HIV interventions have broader population-level benefits, including TB reductions.

Novel automated AIMLAM for diagnosis of Mycobacterium tuberculosis

Aim: A rapid and precise diagnostic method is crucial for timely intervention and management of tuberculosis. The present study compared the diagnostic accuracy of a novel lipoarabinomannan (LAM) antigen test, AIMLAM, for tuberculosis in urine samples. Methodology: The study subjected 106 TB suspects to smear microscopy, MGIT, GeneXpert and AIMLAM. Results: Among 106, smear microscopy identified 36 as positive (33%) (sensitivity; 70.93%, 95% CI (60.14-80.22%), while MGIT showed 38 positive (36.8%). GeneXpert detected 59 positives (sensitivity; 96.83, 95% CI (89.00-99.61%)). AIMLAM declared 61 as positive (57.5%) (sensitivity; 100.00, 95% CI (94.13-100.00%) and 45 as negative (42.5%). Conclusion: Overall, AIMLAM demonstrated better diagnostic accuracy than GeneXpert Assay, smear microscopy and MGIT liquid culture in urine samples.

Contact investigation in multidrug-resistant tuberculosis: ethical challenges

Contact investigation is an evidence-based intervention of multidrug-resistant tuberculosis (MDR-TB) to protect public health by interrupting the chain of transmission. In pursuit of contact investigation, patients' MDR-TB status has to be disclosed to third parties (to the minimum necessary) for tracing the contacts. Nevertheless, disclosure to third parties often unintentionally leads the MDR-TB patients suffered from social discrimination and stigma. For this reason, patients are less inclined to reveal their MDR-TB status and becomes a significant issue in contact investigation. This issue certainly turns into a negative impact on the public interest. Tension between keeping MDR-TB status confidential and safeguarding public health arises in relation to this issue. Regarding MDR-TB management, patient compliance with treatment and contact investigation are equally important. Patients might fail to comply with anti-TB therapy and be reluctant to seek healthcare due to disclosure concerns. In order to have treatment adherence, MDRTB patients should not live through social discrimination and stigma arising from disclosure and TB team has a duty to support them as a mean of reciprocity. However, implementation of contact investigation as a public health policy can still be challenging even with promising reciprocal support to the patients because MDR-TB patients are living in different contexts and situations. There can be no straight forward settlement but an appropriate justification for each distinct context is needed to strike a balance between individual confidentiality and public interest.

The Impact of Preventive Treatment for Multidrug- and Rifampin-Resistant Tuberculosis Exceeds Trial-Based Estimates

BACKGROUND

Several clinical trials of tuberculosis preventive treatment (TPT) for household contacts of patients with multidrug- or rifampin-resistant tuberculosis (MDR/RR-TB) are nearing completion. The potential benefits of delivering TPT to MDR/RR-TB contacts extend beyond the outcomes that clinical trials can measure.

METHODS

We developed an agent-based, household-structured TB and MDR/RR-TB transmission model, calibrated to an illustrative setting in India. We simulated contact investigation in households of patients with MDR/RR-TB, comparing an MDR/RR-TPT regimen (assuming 6-month duration, 70% efficacy) and associated active case finding against alternatives of contact investigation without TPT or no household intervention. We simulated the TB and MDR/RR-TB incidence averted relative to placebo over 2 years, as measurable by a typical trial, as well as the incidence averted over a longer time horizon, in the broader population, and relative to no contact investigation.

RESULTS

Observing TPT and placebo recipients for 2 years as in a typical trial, MDR/RR-TPT was measured to prevent 72% (interquartile range, 45%-100%) of incident MDR/RR-TB among recipients; the median number needed to treat (NNT) to prevent 1 MDR/RR-TB case was 73, compared to placebo. This NNT decreased to 54 with 13-18 years of observation, to 27 when downstream transmission effects were also considered, and to 12 when the effects of active TB screening were included by comparing to a no-household-contact-intervention scenario.

CONCLUSIONS

If forthcoming trial results demonstrate efficacy, the long-term population impact of TPT for MDR/RR-TB-including the large effect of increased active TB detection among MDR/RR-TB contacts-could be much greater than suggested by trial outcomes alone.

Incidence and risk factors of tuberculosis among 420 854 household contacts of patients with tuberculosis in the 100 Million Brazilian Cohort (2004-18): a cohort study

BACKGROUND

Although household contacts of patients with tuberculosis are known to be particularly vulnerable to tuberculosis, the published evidence focused on this group at high risk within the low-income and middle-income country context remains sparse. Using nationwide data from Brazil, we aimed to estimate the incidence and investigate the socioeconomic and clinical determinants of tuberculosis in a cohort of contacts of tuberculosis patients.

METHODS

In this cohort study, we linked individual socioeconomic and demographic data from the 100 Million Brazilian Cohort to mortality data and tuberculosis registries, identified contacts of tuberculosis index patients diagnosed from Jan 1, 2004 to Dec 31, 2018, and followed up the contacts until the contact's subsequent tuberculosis diagnosis, the contact's death, or Dec 31, 2018. We investigated factors associated with active tuberculosis using multilevel Poisson regressions, allowing for municipality-level and household-level random effects.

FINDINGS

We studied 420 854 household contacts of 137 131 tuberculosis index patients. During the 15 years of follow-up (median 4·4 years [IQR 1·9-7·6]), we detected 8953 contacts with tuberculosis. The tuberculosis incidence among contacts was 427·8 per 100 000 person-years at risk (95% CI 419·1-436·8), 16-times higher than the incidence in the general population (26·2 [26·1-26·3]) and the risk was prolonged. Tuberculosis incidence was associated with the index patient being preschool aged (<5 years; adjusted risk ratio 4·15 [95% CI 3·26-5·28]) or having pulmonary tuberculosis (2·84 [2·55-3·17]).

INTERPRETATION

The high and sustained risk of tuberculosis among contacts reinforces the need to systematically expand and strengthen contact tracing and preventive treatment policies in Brazil in order to achieve national and international targets for tuberculosis elimination.

FUNDING

Wellcome Trust and Brazilian Ministry of Health.

Mucosal and systemic antigen-specific antibody responses correlate with protection against active tuberculosis in nonhuman primates

BACKGROUND

Increasing evidence supports that antibodies can protect against active tuberculosis (TB) but knowledge of potentially protective antigens, especially in the airways, is limited. The main objective of this study was to identify antigen-specific airway and systemic immunoglobulin isotype responses associated with the outcome of controlled latent Mycobacterium tuberculosis (Mtb) infection (LTBI) versus uncontrolled infection (TB) in nonhuman primates.

METHODS

In a case-control design, using non-parametric group comparisons with false discovery rate adjustments, we assessed antibodies in 57 cynomolgus macaques which, following low-dose airway Mtb infection, developed either LTBI or TB. We investigated airway and systemic IgG, IgA, and IgM responses in paired bronchoalveolar lavage and plasma samples prior to, two-, and 5-6-months post Mtb infection using an antigen-unbiased approach with Mtb glycan and proteome-wide microarrays.

FINDINGS

Macaques that developed LTBI (n = 36) had significantly increased airway and plasma IgA reactivities to specific arabinomannan (AM) motifs prior to Mtb infection compared to those that developed TB (n = 21; p < 0.01, q < 0.05). Furthermore, LTBI macaques had higher plasma IgG reactivity to protein MTB32A (Rv0125) early post Mtb infection (p < 0.05) and increasing airway IgG responses to some proteins over time.

INTERPRETATION

Our results support a protective role of pre-existing mucosal (lung) and systemic IgA to specific Mtb glycan motifs, suggesting that prior exposure to nontuberculous mycobacteria could be protective against TB. They further suggest that IgG to Mtb proteins early post infection could provide an additional protective mechanism. These findings could inform TB vaccine development strategies.

FUNDING

NIH/NIAID AI117927, AI146329, and AI127173 to JMA.

Public Health Impact and Cost-Effectiveness of Screening for Active Tuberculosis Disease or Infection Among Children in South Africa

BACKGROUND

Although tuberculosis disease is a leading cause of global childhood mortality, there remain major gaps in diagnosis, treatment, and prevention in children because tuberculosis control programs rely predominantly on presentation of symptomatic children or contact tracing. We assessed the public health impact and cost-effectiveness of age-based routine screening and contact tracing in children in South Africa.

METHODS

We used a deterministic mathematical model to evaluate age-based routine screening in 1-year increments from ages 0 to 5 years, with and without contact tracing and preventive treatment. Screening incorporated symptom history and tuberculin skin testing, with chest x-ray and GeneXpert Ultra for confirmatory testing. We projected tuberculosis cases, deaths, disability-adjusted life years (DALYs), and costs (in 2021 U.S. dollars) and evaluated the incremental cost-effectiveness ratios comparing each intervention.

RESULTS

Routine screening at age 2 years with contact tracing and preventive treatment averted 11 900 tuberculosis cases (95% confidence interval [CI]: 6160-15 730), 1360 deaths (95% CI: 260-3800), and 40 000 DALYs (95% CI: 13 000-100 000) in the South Africa pediatric population over 1 year compared with the status quo. This combined strategy was cost-effective (incremental cost-effectiveness ratio $9050 per DALY; 95% CI: 2890-22 920) and remained cost-effective above an annual risk of infection of 1.6%. For annual risk of infection between 0.8% and 1.6%, routine screening at age 2 years was the dominant strategy.

CONCLUSIONS

Routine screening for tuberculosis among young children combined with contact tracing and preventive treatment would have a large public health impact and be cost-effective in preventing pediatric tuberculosis deaths in high-incidence settings such as South Africa.

Finding and treating both tuberculosis disease and latent infection during population-wide active case finding for tuberculosis elimination

In recognition of the high rates of undetected tuberculosis in the community, the World Health Organization (WHO) encourages targeted active case finding (ACF) among "high-risk" populations. While this strategy has led to increased case detection in these populations, the epidemic impact of these interventions has not been demonstrated. Historical data suggest that population-wide (untargeted) ACF can interrupt transmission in high-incidence settings, but implementation remains lacking, despite recent advances in screening tools. The reservoir of latent infection-affecting up to a quarter of the global population -complicates elimination efforts by acting as a pool from which future tuberculosis cases may emerge, even after all active cases have been treated. A holistic case finding strategy that addresses both active disease and latent infection is likely to be the optimal approach for rapidly achieving sustainable progress toward TB elimination in a durable way, but safety and cost effectiveness have not been demonstrated. Sensitive, symptom-agnostic community screening, combined with effective tuberculosis treatment and prevention, should eliminate all infectious cases in the community, whilst identifying and treating people with latent infection will also eliminate tomorrow's tuberculosis cases. If real strides toward global tuberculosis elimination are to be made, bold strategies are required using the best available tools and a long horizon for cost-benefit assessment.

1-Year Incidence of Tuberculosis Infection and Disease Among Household Contacts of Rifampin- and Multidrug-Resistant Tuberculosis

BACKGROUND

Tuberculosis infection (TBI) and TB disease (TBD) incidence remains poorly described following household contact (HHC) rifampin-/multidrug-resistant TB exposure. We sought to characterize TBI and TBD incidence at 1 year in HHCs and to evaluate TB preventive treatment (TPT) use in high-risk groups.

METHODS

We previously conducted a cross-sectional study of HHCs with rifampin-/multidrug-resistant TB in 8 high-burden countries and reassessed TBI (interferon-gamma release assay, HHCs aged ≥5 years) and TBD (HHCs all ages) at 1 year. Incidence was estimated across age and risk groups (<5 years; ≥5 years, diagnosed with human immunodeficiency virus [HIV]; ≥5 years, not diagnosed with HIV/unknown, baseline TBI-positive) by logistic or log-binomial regression fitted using generalized estimating equations.

RESULTS

Of 1016 HHCs, 850 (83.7%) from 247 households were assessed (median, 51.4 weeks). Among 242 HHCs, 52 tested interferon-gamma release assay-positive, yielding a 1-year 21.6% (95% confidence interval [CI], 16.7-27.4) TBI cumulative incidence. Sixteen of 742 HHCs developed confirmed (n = 5), probable (n = 3), or possible (n = 8) TBD, yielding a 2.3% (95% CI, 1.4-3.8) 1-year cumulative incidence (1.1%; 95% CI, .5-2.2 for confirmed/probable TBD). TBD relative risk was 11.5-fold (95% CI, 1.7-78.7), 10.4-fold (95% CI, 2.4-45.6), and 2.9-fold (95% CI, .5-17.8) higher in age <5 years, diagnosed with HIV, and baseline TBI high-risk groups, respectively, vs the not high-risk group (P = .0015). By 1 year, 4% (21 of 553) of high-risk HHCs had received TPT.

CONCLUSIONS

TBI and TBD incidence continued through 1 year in rifampin-/multidrug-resistant TB HHCs. Low TPT coverage emphasizes the need for evidence-based prevention and scale-up, particularly among high-risk groups.

A half-century of research on tuberculosis: Successes and challenges

Great progress has been made over the past half-century, but TB remains a formidable global health problem, particularly in low- and middle-income countries. Understanding the mechanisms of pathogenesis and necessary and sufficient conditions for protection are critical. The need for inexpensive and sensitive point-of-care diagnostic tests for earlier detection of infection and disease, shorter and less-toxic drug regimens for drug-sensitive and -resistant TB, and a more effective vaccine than BCG is immense. New and better tools, greater support for international research, collaborations, and training will be required to dramatically reduce the burden of this devastating disease which still kills 1.6 million people annually.

A user-centred implementation strategy for tuberculosis contact investigation in Uganda: protocol for a stepped-wedge, cluster-randomised trial

BACKGROUND

Tuberculosis(TB) is among the leading causes of infectious death worldwide. Contact investigation is an evidence-based, World Health Organisation-endorsed intervention for timely TB diagnosis, treatment, and prevention but has not been widely and effectively implemented.

METHODS

We are conducting a stepped-wedge, cluster-randomised, hybrid Type III implementation-effectiveness trial comparing a user-centred to a standard strategy for implementing TB contact investigation in 12 healthcare facilities in Uganda. The user-centred strategy consists of several client-focused components including (1) a TB-education booklet, (2) a contact-identification algorithm, (3) an instructional sputum-collection video, and (4) a community-health-rider service to transport clients, CHWs, and sputum samples, along with several healthcare-worker-focused components, including (1) collaborative improvement meetings, (2) regular audit-and-feedback reports, and (3) a digital group-chat application designed to develop a community of practice. Sites will cross-over from the standard to the user-centred strategy in six, eight-week transition steps following a randomly determined site-pairing scheme and timeline. The primary implementation outcome is the proportion of symptomatic close contacts completing TB evaluation within 60 days of TB treatment initiation by the index person with TB. The primary clinical effectiveness outcomes are the proportion of contacts diagnosed with and initiating active TB disease treatment and the proportion initiating TB preventative therapy within 60 days. We will assess outcomes from routine source documents using intention-to-treat analyses. We will also conduct nested mixed-methods studies of implementation fidelity and context and perform cost-effectiveness and impact modelling. The Makerere School of Public Health IRB(#554), the Uganda National Council for Science and Technology(#HS1720ES), and the Yale Institutional Review Board(#2000023199) approved the study and waived informed consent for the main trial implementation-effectiveness outcomes. We will submit results for publication in peer-reviewed journals and disseminate findings to local policymakers and representatives of affected communities.

DISCUSSION

This pragmatic, quasi-experimental implementation trial will inform efforts to find and prevent undiagnosed persons with TB in high-burden settings using contact investigation. It will also help assess the suitability of human-centred design and communities of practice for tailoring implementation strategies and sustaining evidence-based interventions in low-and-middle-income countries.

TRIAL REGISTRATION

The trial was registered(ClinicalTrials.gov Identifier NCT05640648) on 16 November 2022, after the trial launch on 7 March 2022.

Exploring stakeholders perspectives on TB contact investigation in Cali, Colombia: a qualitative study

Introduction

Contact investigation is a proven intervention for tuberculosis (TB) case finding and prevention. Although widely endorsed by national public health authorities and the World Health Organization, many countries struggle to implement it effectively. The objective of the study is to describe and characterize the barriers and facilitators of TB contact investigation in Cali, Colombia from the perspective and experience of the key stakeholders involved.

Methods

We collected data from group discussions during two workshop sessions with clinic and public health staff involved in TB contact investigation (June 2019 and March 2020 respectively) and semi-structured interviews with TB cases and their household contacts (July 2019 to April 2020). We undertook an inductive thematic analysis with the RADaR technique to characterize the barriers and facilitators of the TB contact investigation process.

Results

The two workshops included 21 clinics and 12 public health staff. We also conducted 26 semi-structured interviews with TB cases and their household contacts. Using thematic analysis, we identified four common themes: Healthcare Operations, Essential Knowledge, Time Limitations and Competing Responsibilities, and Interpersonal Interactions. The main barriers to conducting household visits were low data quality, stigma and mistrust, safety concerns for health workers, and limited resources. The main barriers to TB uptake by contacts were competing responsibilities, low TB risk perceptions among contacts, and difficulty accessing diagnostic tests for contacts. In contrast, good communication and social skills among health workers and accurate TB knowledge facilitated successful household visits and TB test uptake, according to key stakeholders.

Conclusion

This study provides a deeper understanding of TB contact investigation barriers and facilitators in a high-prevalence urban setting in a middle-income country from the perspective and experience of key stakeholders. The study shed light on the barriers that hinder household contacts engagement and TB test uptake such as issues of systemic capacity and TB knowledge. Also, highlighted facilitators such as the importance of interpersonal communication skills among health workers in the public and private sector. The insights from this study can serve as a valuable resource for public health organizations seeking to enhance their contact investigation efforts and improve TB control in similar settings.

Strategies to increase childhood tuberculosis case detection at the primary health care level: Lessons from an active case finding study in Zambia

INTRODUCTION

In high TB burden settings, it is estimated that 10-20% of total notifications should be children, however, currently only 6-8% of the total TB notifications in Zambia are children. We assessed whether the implementation of a multicomponent strategy, at primary healthcare facilities, that systematically targets barriers at each step of the childhood TB diagnostic cascade can increase childhood TB case detection.

METHODS

We conducted a controlled, interrupted time series analysis to compare childhood TB case notifications before (January 2018-December 2019), and during implementation (January 2020-September 2021) in two intervention and two control Level 1 hospitals in Lusaka, Zambia. At each of the intervention facilities, we implemented a multicomponent strategy constituting: (1) capacity development on childhood TB and interpretation of chest x-ray, (2) TB awareness-raising and demand creation activities, (3) setting up fast track TB services, (4) strengthening of household contact tracing, and (5) improving access to digital chest X-ray for TB screening and Xpert MTB/Rif Ultra for TB diagnosis, through strengthening sample collection in children.

FINDINGS

Among 5,150 children < 15 years screened at the two intervention facilities during the study period, 503 (9.8% yield) were diagnosed with TB. Of these, 433 (86.1%) were identified through facility-based activities (10.5% yield) and 70 (13.9%) were identified through household contact tracing (6.9% yield). Overall, 446 children (88.7%) children with TB were clinically diagnosed. Following implementation of the multicomponent strategy, the proportion children contributed to total TB notifications immediately changed by +1.5% (95%CI: -3.5, 6.6) and -4.4% (95%CI: -7.5, 1.4) at the intervention and control sites, respectively (difference 6.0% [95%CI: -0.7, 12.7]), p = 0.08); the proportion of childhood notifications increased 0.9% (95%CI: -0.7, 2.5%) each quarter at the intervention sites relative to pre-implementation trends, while declining 1.2% (-95%CI: -1.8, -0.6) at the control sites (difference 2.1% [95%CI: 0.1, 4.2] per quarter between, p = 0.046); this translated into 352 additional and 85 fewer childhood TB notifications at the intervention and control sites, respectively, compared to the pre-implementation period.

CONCLUSION

A standardized package of strategies to improve childhood TB detection at primary healthcare facilities was feasible to implement and was associated with a sustained improvement in childhood TB notifications.

Analysis of factors influencing patient delay by patients with pulmonary tuberculosis in Lishui City, Zhejiang Province

OBJECTIVE

The purpose of this study was to collect data on the current state of patient delay by patients with tuberculosis (TB) in Lishui City, Zhejiang Province who were under the care of a TB-designated hospital from 2011 to 2021 and to analyze the factors that contribute to this problem in order to provide a scientific basis for the prevention and control of TB.

METHODS

In this observational study, we collected data on patients with pulmonary TB that were reported to the Chinese government's disease prevention and control information system by the Traditional Chinese Medicine Hospital in Lishui City between 2011 and 2021. The data included demographics like age, gender, occupation, household registration, current address, date of symptoms, date of first visit, and etiology results. Multivariate logistic regression analysis was used to analyze the factors influencing patient delay by patients with pulmonary TB.

RESULTS

There were 3,190 cases of pulmonary TB treated in a TB-designated hospital in Lishui City, Zhejiang Province, between 2011 and 2021. Of these, 2,268 involved patient delay, with the delay rate of 71.10% and the median (Q25, Q75) days of patient delay being 36 (25, 72) days. Results of multivariate logistic regression analysis indicated the presence of risk factors-age > 60 years old (OR = 1.367, 95% CI: 1.144 ~ 1.632), pathogen positive (OR = 1.211, 95% CI: 1.033 ~ 1.419), and employed as peasants (OR = 1.353, 95% CI:1.144 ~ 1.601) for patient delay in patients with pulmonary TB. Patients with diabetes mellitus made up 64.94% of the pulmonary TB population, which was lower than the 71.58% of patients without diabetes mellitus (χ² = 4.602, P = 0.032). Additionally, the presence of diabetes mellitus may be a protective factor in patient delay in patients with pulmonary TB (OR = 0.641, 95% CI: 0.481 ~ 0.856).

CONCLUSION

High rates of patient delay, age > 60 years old, a positive etiology, and being employed as peasants are all possible risk factors for pulmonary TB in Lishui City, Zhejiang Province.

A user-centred implementation strategy for tuberculosis contact investigation in Uganda: Protocol for a stepped-wedge, cluster-randomised trial

Background Tuberculosis (TB) is among the leading causes of infectious death worldwide. Contact investigation is an evidence-based, World Health Organisation-endorsed intervention for timely TB diagnosis, treatment, and prevention but has not been widely and effectively implemented. Methods We are conducting a stepped-wedge, cluster-randomised, hybrid Type III implementation-effectiveness trial comparing a user-centred to a standard strategy for implementing TB contact investigation in 12 healthcare facilities in Uganda. The user-centred strategy consists of several client-focused components including 1) a TB-education booklet, 2) a contact-identification algorithm, 3) an instructional sputum-collection video, and 4) a community-health-rider service to transport clients, CHWs, and sputum samples, along with several healthcare-worker-focused components, including 1) collaborative improvement meetings, 2) regular audit-and-feedback reports, and 3) a digital group-chat application designed to develop a community of practice. Sites will cross from the standard to the user-centred strategy in six, eight-week transition steps following a randomly determined site-pairing scheme and timeline. The primary implementation outcome is the proportion of symptomatic close contacts completing TB evaluation within 60 days of TB treatment initiation by the index person with TB. The primary clinical effectiveness outcomes are the proportion of contacts diagnosed with and initiating active TB disease treatment and the proportion initiating TB preventative therapy within 60 days. We will assess outcomes from routine source documents using intention-to-treat analyses. We will also conduct nested mixed-methods studies of implementation fidelity and context and perform cost-effectiveness and impact modelling. The Makerere School of Public Health IRB (#554), the Uganda National Council for Science and Technology (#HS1720ES), and the Yale Institutional Review Board (#2000023199) approved the study with a waiver of informed consent for the main trial implementation-effectiveness outcomes. We will submit trial results for publication in a peer-reviewed journal and disseminate findings to local shareholders, including policymakers and representatives of affected communities. Discussion This pragmatic, quasi-experimental implementation trial will inform efforts to find and prevent undiagnosed persons with TB in high-burden setting using contact investigation. It will help assess the suitability of human-centred design and communities of practice for tailoring implementation strategies and sustain evidence-based interventions in low-and-middle-income countries. Trial registration number ClinicalTrials.gov Identifier: NCT05640648.

mHealth to improve implementation of TB contact investigation: a case study from Uganda

BACKGROUND

Implementation science offers a systematic approach to adapting innovations and delivery strategies to new contexts but has yet to be widely applied in low- and middle-income countries. The Fogarty Center for Global Health Studies is sponsoring a special series, "Global Implementation Science Case Studies," to address this gap.

METHODS

We developed a case study for this series describing our approach and lessons learned while conducting a prospective, multi-modal study to design, implement, and evaluate an implementation strategy for TB contact investigation in Kampala, Uganda. The study included formative, evaluative, and summative phases that allowed us to develop and test an adapted contact investigation intervention involving home-based sample collection for TB and HIV testing. We concurrently developed a multi-component mHealth implementation strategy involving fingerprint scanning, electronic decision support, and automated reporting of test results via text message. We then conducted a household-randomized, hybrid implementation-effectiveness trial comparing the adapted intervention and implementation strategy to usual care. Our assessment included nested quantitative and qualitative studies to understand the strategy's acceptability, appropriateness, feasibility, fidelity, and costs. Reflecting on this process with a multi-disciplinary team of implementing researchers and local public health partners, we provide commentary on the previously published studies and how the results influenced the adaptation of international TB contact investigation guidelines to fit the local context.

RESULTS

While the trial did not show improvements in contact investigation delivery or public health outcomes, our multi-modal evaluation strategy helped us identify which elements of home-based, mHealth-facilitated contact investigation were feasible, acceptable, and appropriate and which elements reduced its fidelity and sustainability, including high costs. We identified a need for better tools for measuring implementation that are simple, quantitative, and repeatable and for greater attention to ethical issues in implementation science.

CONCLUSIONS

Overall, a theory-informed, community-engaged approach to implementation offered many learnings and actionable insights for delivering TB contact investigation and using implementation science in low-income countries. Future implementation trials, especially those incorporating mHealth strategies, should apply the learnings from this case study to enhance the rigor, equity, and impact of implementation research in global health settings.

Population-level health and economic impacts of introducing Vaccae vaccination in China: a modelling study

INTRODUCTION

Given the ageing epidemic of tuberculosis (TB), China is facing an unprecedented opportunity provided by the first clinically approved next-generation TB vaccine Vaccae, which demonstrated 54.7% efficacy for preventing reactivation from latent infection in a phase III trial. We aim to assess the population-level health and economic impacts of introducing Vaccae vaccination to inform policy-makers.

METHODS

We evaluated a potential national Vaccae vaccination programme in China initiated in 2024, assuming 20 years of protection, 90% coverage and US$30/dose government contract price. An age-structured compartmental model was adapted to simulate three strategies: (1) no Vaccae; (2) mass vaccination among people aged 15-74 years and (3) targeted vaccination among older adults (60 years). Cost analyses were conducted from the healthcare sector perspective, discounted at 3%.

RESULTS

Considering postinfection efficacy, targeted vaccination modestly reduced TB burden (~20%), preventing cumulative 8.01 (95% CI 5.82 to 11.8) million TB cases and 0.20 (0.17 to 0.26) million deaths over 2024-2050, at incremental cost-effectiveness ratio of US$4387 (2218 to 10 085) per disability adjusted life year averted. The implementation would require a total budget of US$22.5 (17.6 to 43.4) billion. In contrast, mass vaccination had a larger bigger impact on the TB epidemic, but the overall costs remained high. Although both preinfection and postinfection vaccine efficacy type might have a maximum impact (>40% incidence rate reduction in 2050), it is important that the vaccine price does not exceed US$5/dose.

CONCLUSION

Vaccae represents a robust and cost-effective choice for TB epidemic control in China. This study may facilitate the practice of evidence-based strategy plans for TB vaccination and reimbursement decision making.

Contact investigation of tuberculosis in Shanghai, China: A 13-year cohort

OBJECTIVES

Tuberculosis (TB) contact investigation is an effective strategy for TB control. We established a close-contact cohort to evaluate the effect of contact investigation in Shanghai, China.

METHODS

Close contacts of bacteria-positive TB cases diagnosed from 2009 to 2018 in the Songjiang District of Shanghai were screened and followed up until 2021 through symptom examination or other alternatives, and the incidence and risk factors for developing active TB among close contacts were assessed by survival analysis and WGS.

RESULTS

7018 close contacts of 2861 bacteria-positive TB cases were investigated. The median follow-up time was 7.4 years. 97 close contacts (185/100,000, 95%CI: 151-226) developed TB. Survival analysis showed that index cases who were in younger age groups, living in urban settings, smear-positive, and reported a healthcare-seeking delay for TB had higher risks of generating contact cases. Close contacts with matched strains developed TB at an average of 26.5 months based on WGS.

CONCLUSION

A 2-year ideally longer follow-up for close contacts would be beneficial. To improve early case detection, more attention needs to be paid to those contacts whose index cases were living in urban settings, were smear-positive, had a healthcare-seeking delay for TB, and/or were aged ≤18 years.

Optimising diagnosis and treatment of tuberculosis infection in community and primary care settings in two urban provinces of Viet Nam: a cohort study

OBJECTIVES

To end tuberculosis (TB), the vast reservoir of 1.7-2.3 billion TB infections (TBIs) must be addressed, but achieving global TB preventive therapy (TPT) targets seems unlikely. This study assessed the feasibility of using interferon-γ release assays (IGRAs) at lower healthcare levels and the comparative performance of 3-month and 9-month daily TPT regimens (3HR/9H).

DESIGN, SETTING, PARTICIPANTS AND INTERVENTION

This cohort study was implemented in two provinces of Viet Nam from May 2019 to September 2020. Participants included household contacts (HHCs), vulnerable community members and healthcare workers (HCWs) recruited at community-based TB screening events or HHC investigations at primary care centres, who were followed up throughout TPT.

PRIMARY AND SECONDARY OUTCOMES

We constructed TBI care cascades describing indeterminate and positivity rates to assess feasibility, and initiation and completion rates to assess performance. We fitted mixed-effects logistic and stratified Cox models to identify factors associated with IGRA positivity and loss to follow-up (LTFU).

RESULTS

Among 5837 participants, the indeterminate rate was 0.8%, and 30.7% were IGRA positive. TPT initiation and completion rates were 63.3% (3HR=61.2% vs 9H=63.6%; p=0.147) and 80.6% (3HR=85.7% vs 9H=80.0%; p=0.522), respectively. Being male (adjusted OR=1.51; 95% CI: 1.28 to 1.78; p<0.001), aged 45-59 years (1.30; 1.05 to 1.60; p=0.018) and exhibiting TB-related abnormalities on X-ray (2.23; 1.38 to 3.61; p=0.001) were associated with positive IGRA results. Risk of IGRA positivity was lower in periurban districts (0.55; 0.36 to 0.85; p=0.007), aged <15 years (0.18; 0.13 to 0.26; p<0.001), aged 15-29 years (0.56; 0.42 to 0.75; p<0.001) and HCWs (0.34; 0.24 to 0.48; p<0.001). The 3HR regimen (adjusted HR=3.83; 1.49 to 9.84; p=0.005) and HCWs (1.38; 1.25 to 1.53; p<0.001) showed higher hazards of LTFU.

CONCLUSION

Providing IGRAs at lower healthcare levels is feasible and along with shorter regimens may expand access and uptake towards meeting TPT targets, but scale-up may require complementary advocacy and education for beneficiaries and providers.

Trials underestimate the impact of preventive treatment for household contacts exposed to multidrug-resistant tuberculosis: a simulation study

Background

Several clinical trials of tuberculosis preventive treatment (TPT) for household contacts of patients with multidrug-resistant tuberculosis (MDR-TB) are nearing completion. The potential benefits of TPT for MDR-TB contacts extend beyond the outcomes that clinical trials can measure.

Methods

We developed an agent-based, household-structured TB and MDR-TB transmission model, calibrated to an illustrative setting in India, the country accounting for 26% of global MDR-TB burden. We simulated household contact investigation for contacts of patients with MDR-TB, comparing an MDR-TPT regimen against alternatives of isoniazid preventive treatment, household contact investigation without TPT, or no household contact intervention. We simulated outcomes of a clinical trial and estimated the patient-level and population-level effects over a longer time horizon.

Findings

During two years of follow-up per recipient, a simulated 6-month MDR-TPT regimen with 70% efficacy against both DS- and MDR-TB infection could prevent 72% [Interquartile range (IQR): 45 - 100%] of incident MDR-TB among TPT recipients (number needed to treat (NNT) 73 [44 - 176] to prevent one MDR-TB case), compared to household contact investigation without TPT. This NNT decreased to 54 [30 - 183] when median follow-up was increased from two to 16 years, to 27 [11 - Inf] when downstream transmission effects were also considered, and to 12 [8 - 22] when these effects were compared to a scenario of no household contact intervention.

Interpretation

If forthcoming trial results demonstrate efficacy, the long-term population impact of MDR-TPT implementation could be much greater than suggested by trial outcomes alone.

Funding

NIH K01AI138853 and K08AI127908; Johns Hopkins Catalyst Award.

Positive rate and risk factors of latent tuberculosis infection among persons living with HIV in Jiangsu Province, China

Objective

To analyze the latent tuberculosis infection (LTBI) among persons living with HIV(PLWH) in Jiangsu Province, to explore the factors affecting the positive rate of LTBI, and to take appropriate measures to control tuberculosis (TB) infection.

Methods

A cross-sectional study was conducted among PLWH in Jiangsu Province from June to July 2021. All PLWH in Jiangsu Province were used as the study population. Currently, the diagnosis of LTBI lacks a "gold standard" and can only be assisted by the immunological method. In this study, Tuberculin skin test (TST), ESAT6-CFP10 test (EC), and QuantiFERON-TB gold in-tube (QFT) were used to detect the positive rate of LTBI among PLWH and to analyze their risk factors.

Results

A total of 340 prisoners were included, 89.7% were male, the median age was 38 years [Interquartile Range (IQR):32-46 years], these patients were on Antiviral Therapy (ART), and median CD4 counts was 376 (IQR: 261-496), 103 (30.3%) were positive in at least one test, LTBI by TST was 16.5%, LTBI by EC was 15.9%, LTBI by QFT was 26.2%. Univariate analysis showed the results for TST, EC, and QFT were not affected by CD4 counts (p>0.05), and multivariate analysis showed that a history of incarceration was associated with an increased risk of positive TST (adjusted odds ratio [aOR]=1.98;95% CI,1.03-3.82), EC (aOR=2.65;95% CI,1.37-5.12) and QFT (aOR=2.01;95%CI,1.12-3.57), in addition, female gender was associated with increased risk of positive TST (aOR=3.66;95%CI,1.60-8.37) and EC (aOR=3.43;95%CI,1.46-8.07), and contact history of TB patients was associated with increased risk of TST (aOR= 2.54;95%CI,1.23-5.22) and QFT (aOR=2.03;95%CI,1.03-3.99), and ethnic minorities (aOR=0.26;95%CI,0.12-0.57), longer duration of incarceration was associated with an increased risk of positive QFT (aOR=1.12;95%CI,1.02-1.24). Conclusions Female gender, and ethnic minorities, history of incarceration, longer duration of incarceration, and contact history of TB patients are risk factors for LTBI among PLWH in Jiangsu Province, and attention should be paid to TB control in this population.

Mycobacterium tuberculosis Transmission in High-Incidence Settings-New Paradigms and Insights

Tuberculosis has affected humankind for thousands of years, but a deeper understanding of its cause and transmission only arose after Robert Koch discovered Mycobacterium tuberculosis in 1882. Valuable insight has been gained since, but the accumulation of knowledge has been frustratingly slow and incomplete for a pathogen that remains the number one infectious disease killer on the planet. Contrast that to the rapid progress that has been made in our understanding SARS-CoV-2 (the cause of COVID-19) aerobiology and transmission. In this Review, we discuss important historical and contemporary insights into M. tuberculosis transmission. Historical insights describing the principles of aerosol transmission, as well as relevant pathogen, host and environment factors are described. Furthermore, novel insights into asymptomatic and subclinical tuberculosis, and the potential role this may play in population-level transmission is discussed. Progress towards understanding the full spectrum of M. tuberculosis transmission in high-burden settings has been hampered by sub-optimal diagnostic tools, limited basic science exploration and inadequate study designs. We propose that, as a tuberculosis field, we must learn from and capitalize on the novel insights and methods that have been developed to investigate SARS-CoV-2 transmission to limit ongoing tuberculosis transmission, which sustains the global pandemic.

Determinants of losses in the tuberculosis infection cascade of care among children and adolescent contacts of pulmonary tuberculosis cases: A Brazilian multi-centre longitudinal study

Background

Approximately 10% of the global tuberculosis (TB) burden is in children. Identification, diagnosis, and early treatment of Mycobacterium tuberculosis infection (TBI) is critical to prevent progression to TB in children. The risk of TB, including severe disease, is highest in children <5 years old. We evaluated the cascade of TBI care among child and adolescent TB contacts to identify factors associated with losses in the cascade.

Methods

Close contacts ≤ 18 years old of pulmonary TB patients enrolled between 2015 and 2019 in a multi-centre Brazilian cohort were followed for up to 24 months and classified according to age groups: <5 years, 5-9 years, 10-14 years and 15-18 years. Data on clinical investigation, radiographic examination, IGRA testing at baseline and 6 months, initiation and completion of TB preventive treatment (TPT) were collected. Multivariable regression analyses identified factors associated with TBI and losses in the cascade of care in children and adolescents.

Findings

Among 1795 TB contacts initially identified, 530 (29·5%) were ≤18 years old. Losses for all steps in the cascade were especially high in children <5 years old (88%) because at this age all contacts are recommended to initiate TPT. As a proportion of all children, completion of TPT was low (between 10% and 13%) in all age-groups. Furthermore, multivariable regression revealed that younger age of contacts and TB index cases who were female, had pulmonary cavities, and persistent cough were independently associated with losses in the cascade of care among persons ≤18 years old.

Interpretation

Losses in the TBI cascade were the highest among children <5 years, which was the group at highest risk for TB among the four age groups. The findings highlight the need to improve screening, initiation, and completion of TPT of young children who are close contacts of people with TB in Brazil.

Funding

National Institutes of Allergy and Infectious Diseases.

Early risk assessment in paediatric and adult household contacts of confirmed tuberculosis cases by novel diagnostic tests (ERASE-TB): protocol for a prospective, non-interventional, longitudinal, multicountry cohort study

INTRODUCTION

The WHO End-TB Strategy calls for the development of novel diagnostics to detect tuberculosis (TB) earlier and more accurately. Better diagnostics, together with tools to predict disease progression, are critical for achieving WHO End-TB targets. The Early Risk Assessment in TB Contacts by new diagnoStic tEsts (ERASE-TB) study aims to evaluate novel diagnostics and testing algorithms for early TB diagnosis and accurate prediction of disease progression among household contacts (HHCs) exposed to confirmed index cases in Mozambique, Tanzania and Zimbabwe.

METHODS AND ANALYSIS

A total of 2100 HHCs (aged ≥10 years) of adults with microbiologically-confirmed pulmonary TB will be recruited and followed up at 6-month intervals for 18-24 months. At each time point, a WHO symptom screen and digital chest radiograph (dCXR) will be performed, and blood and urine samples will be collected. Individuals screening positive (WHO symptom screen or dCXR) will be requested to provide sputum for Xpert MTB/Rif Ultra. At baseline, HHCs will also be screened for HIV, diabetes (HbA1c), chronic lung disease (spirometry), hypertension and anaemia. Study outcomes will be coprevalent TB (diagnosed at enrolment), incident TB (diagnosed during follow-up) or no TB at completion of follow-up. Novel diagnostics will be validated using fresh and biobanked samples with a nested case-control design. Cases are defined as HHCs diagnosed with TB (for early diagnosis) or with incident TB (for prediction of progression) and will be matched by age, sex and country to HHCs who remain healthy (controls). Statistical analyses will include assessment of diagnostic accuracy by constructing receiver operating curves and calculation of sensitivity and specificity.

ETHICS AND DISSEMINATION

ERASE-TB has been approved by regulatory and ethical committees in each African country and by each partner organisation. Consent, with additional assent for participants <18 years, is voluntary. Attestation by impartial witnesses is sought in case of illiteracy. Confidentiality of participants is being maintained throughout. Study findings will be presented at scientific conferences and published in peer-reviewed international journals.

TRIAL REGISTRATION NUMBER

NCT04781257.Cite Now.

Gaps and Interventions across the Diagnostic Care Cascade of TB Patients at the Level of Patient, Community and Health System: A Qualitative Review of the Literature

Tuberculosis (TB) continues to be one of the important public health concerns globally, and India is among the seven countries with the largest burden of TB. There has been a consistent increase in the notifications of TB cases across the globe. However, the 2018 estimates envisage a gap of about 30% between the incident and notified cases of TB, indicating a significant number of patients who remain undiagnosed or ‘missed’. It is important to understand who is ‘missed’, find this population, and provide quality care. Given these complexities, we reviewed the diagnostic gaps in the care cascade for TB. We searched Medline via PubMed and CENTRAL databases via the Cochrane Library. The search strategy for PubMed was tailored to individual databases and was as: ((((((tuberculosis[Title/Abstract]) OR (TB[Title/Abstract])) OR (koch *[Title/Abstract])) OR (“tuberculosis”[MeSH Terms]))) AND (((diagnos *) AND (“diagnosis”[MeSH Terms])))). Furthermore, we screened the references list of the potentially relevant studies to seek additional studies. Studies retrieved from these electronic searches and relevant references included in the bibliography of those studies were reviewed. Original studies in English that assessed the causes of diagnostic gaps and interventions used to address them were included. Delays in diagnosis were found to be attributable to both the individuals’ and the health system’s capacity to diagnose and promptly commence treatment. This review provides insights into the diagnostic gaps in a cascade of care for TB and different interventions adopted in studies to close this gap. The major diagnostic gaps identified in this review are as follows: people may not have access to TB diagnostic tests, individuals are at a higher risk of missed diagnosis, services are available but people may not seek care with a diagnostic facility, and patients are not diagnosed despite reaching health facilities. Therefore, reaching the goal to End TB requires putting in place models and methods to provide prompt and quality assured diagnosis to populations at par.

Harnessing new mHealth technologies to Strengthen the Management of Multidrug-Resistant Tuberculosis in Vietnam (V-SMART trial): a protocol for a randomised controlled trial

INTRODUCTION

Multidrug-resistant tuberculosis (MDR-TB) remains a major public health problem globally. Long, complex treatment regimens coupled with frequent adverse events have resulted in poor treatment adherence and patient outcomes. Smartphone-based mobile health (mHealth) technologies offer national TB programmes an appealing platform to improve patient care and management; however, clinical trial evidence to support their use is lacking. This trial will test the hypothesis that an mHealth intervention can improve treatment success among patients with MDR-TB and is cost-effective compared with standard practice.

METHODS AND ANALYSIS

A community-based, open-label, parallel-group randomised controlled trial will be conducted among patients treated for MDR-TB in seven provinces of Vietnam. Patients commencing therapy for microbiologically confirmed rifampicin-resistant or multidrug-resistant tuberculosis within the past 30 days will be recruited to the study. Participants will be individually randomised to an intervention arm, comprising use of an mHealth application for treatment support, or a 'standard care' arm. In both arms, patients will be managed by the national TB programme according to current national treatment guidelines. The primary outcome measure of effectiveness will be the proportion of patients with treatment success (defined as treatment completion and/or bacteriological cure) after 24 months. A marginal Poisson regression model estimated via a generalised estimating equation will be used to test the effect of the intervention on treatment success. A prospective microcosting of the intervention and within-trial cost-effectiveness analysis will also be undertaken from a societal perspective. Cost-effectiveness will be presented as an incremental cost per patient successfully treated and an incremental cost per quality-adjusted life-year gained.

ETHICS

Ethical approval for the study was granted by The University of Sydney Human Research Ethics Committee (2019/676).

DISSEMINATION

Study findings will be disseminated to participants and published in peer-reviewed journals and conference proceedings.

TRIAL REGISTRATION NUMBER

ACTRN12620000681954.

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.

The global impact of household contact management for children on multidrug-resistant and rifampicin-resistant tuberculosis cases, deaths, and health-system costs in 2019: a modelling study

Background

Methods

Findings

Interpretation

Funding

Are pulmonary tuberculosis patients identified by active and by passive case detection different? A cross sectional study in Pakistan

BACKGROUND

Active tuberculosis (TB) case finding by 'extended contact screening' (ECS), was tested during 2013-15.

OBJECTIVES

Our objective was to compare the characteristics of pulmonary TB patients detected by ECS with patients detected by routine passive case finding (PCF).

METHODS

This cross sectional study was based on data collected through ECS and routine program data in Lahore, Faisalabad and Rawalpindi districts and Islamabad in 2015. Characteristics of patients detected by ECS and PCF were compared.

RESULTS

In 12114 patients with pulmonary TB in the study, 4604 (38%) were detected by ECS, 4052 (88%) had bacteriological confirmation. Males represented 56.2%(95%CI 54.8-57.6) in ESC and 49.7%(95%CI 48.6-50.8) in PCF; bacteriologically confirmed cases was 88.0%(95%CI 87.1-88.9) in ECS and 50.3%(95%CI 49.2-51.4). By regression analysis we found that compared to adults aged 15-44 years, children under 15 had higher chance of being detected by ECS (adjusted odds ratio (OR) 2.69; 95%CI 2.21-3.28). There was a higher chance of being detected by ECS in Faisalabad (adjusted OR 2.57; 95%CI 2.01-3.29) compared to Islamabad.

CONCLUSION

Extended contact screening detected a higher proportion of men and children than routine case finding; both these groups are more often undetected by routine TB control.

Supporting tuberculosis program in active contact tracing: a case study from Pakistan

Tuberculosis (TB) is on the rise in Pakistan and there could be multiple reasons including poverty, difficulty in access to TB treatment services, non-compliance with treatment, social stigma etc. According to the TB program managers, limited treatment and testing sites for tuberculosis and lack of trained human resources play a major role in compromising TB management. A major lacuna in the TB control program is the absence of active contact tracing strategy. This is essential for a disease where positive cases are known to be able to infect a further 10‒15 individuals in a year. Tackling tuberculosis in Pakistan has been beleaguered by funding challenges and other systems’ bottlenecks such as lack of skilled human resources and insufficient supply of medicines, despite the fact that disease burden is one of the highest in the world. Although it is a notifiable disease, active case finding, contact tracing and reporting is notoriously low throughout the country. Access to diagnostics and treatment facilities has been limited and stigma attached to the disease remains deeply entrenched among the communities. Researchers have shown that enhanced and active approaches to contact investigation effectively identifies additional patients with TB among household contacts at a relatively modest cost. USAID’s Integrated Health Systems Strengthening and Service Delivery Activity extended support to the Health Departments of Sindh and Khyber Pakhtunkhwa provinces. In collaboration with the two provincial TB programs, community based active contact tracing was conducted on 17,696 individuals, based on the index cases. Among the contacts traced, 243 cases were diagnosed as drug sensitive or drug resistant TB. Awareness sessions were conducted to sensitize people on the various aspects of disease and importance of getting tested. The project also supported establishing three satellite Programmatic Management of Drug Resistant Tuberculosis (PMDT) sites for drug resistant TB treatment, enhancing the programs’ diagnostic and testing capacity.

Scaling up investigation and treatment of household contacts of tuberculosis patients in Brazil: a cost-effectiveness and budget impact analysis

Background

In Brazil, investigation and treatment of tuberculosis infection (TBI) in households contacts (HHC) of TB patients is not a priority. We estimated the cost-effectiveness and budget-impact of scaling-up an enhanced HHC management in Brazil.

Methods

We conceptualized a cascade-of-care that captures how HHC of tuberculosis patients are investigated in Brazil (status quo) and two enhanced strategies for management of HHC focusing on: (1) only tuberculosis disease (TBD) detection and, (2) TBD and TBI detection and treatment. Effectiveness was the number of HHC diagnosed with TBD and completing TBI treatment. Proportions in the cascades-of-care were derived from a meta-analysis. Health-system costs (2019 US$) were based on literature and official data from Brazil. The impact of enhanced strategies was extrapolated using reported data from 2019.

Findings

With the status quo, 0 (95% uncertainty interval: 0-1) HHC are diagnosed with TBD and 2 (0-16) complete TBI treatment. With strategy(1), an additional 15 (3-45) HHC would be diagnosed with TBD at a cost of US$346 each. With strategy(2), 81 (19-226) additional HHC would complete TBI treatment at a cost of US$84 each. A combined strategy, implemented nationally to enhance TBD detection and TBI treatment would result in an additional 9,711 (845-28,693) TBD being detected, and 51,277 (12,028-143,495) more HHC completing TBI treatment each year, utilizing 10.9% and 11.6% of the annual national tuberculosis program budget, respectively.

Interpretation

Enhanced detection and treatment of TBD and TBI among HHC in Brazil can be achieved at a national level using current tools at reasonable cost.

Funding

None.

Knowledge, attitude, and practices regarding childhood tuberculosis detection and management among health care providers in Cambodia: a cross-sectional study

BACKGROUND

The World Health Organization (WHO) estimated that 29% of global tuberculosis (TB) and almost 47% of childhood TB cases were not reported to national TB programs in 2019. In Cambodia, most childhood TB cases were reported from health facilities supported by the Global Fund to Fight AIDS, Tuberculosis, and Malaria in 2019. This study aimed to compare the healthcare providers' knowledge, attitude, and practices (KAP) on childhood TB case detection in operational districts (ODs) with high and low childhood TB case detection in Cambodia.

METHODS

We conducted a cross-sectional study between November and December 2020 among healthcare providers in 10 purposively selected ODs with high childhood TB case detection and 10 ODs with low childhood TB case detection. A total of 110 healthcare providers from referral hospitals (RHs) and 220 from health centers (HCs) were interviewed. We collected information on socio-demographic characteristics, training, and KAP on childhood TB. Pearson's Chi-square or Fisher's exact and Student's t-tests were performed to explore the differences in KAP of healthcare providers from ODs with low vs. high childhood TB detection.

RESULTS

Of the 330 respondents, 193 were from ODs with high childhood TB case detection, and 66.67% were from HCs. A significantly higher proportion (46.11%) of respondents from ODs with high childhood TB case detection received training on childhood TB within the past two years than those from low childhood TB case detection ODs (34.31%) (p = 0.03). Key knowledge on childhood TB was not significantly different among respondents from ODs with high and low childhood TB case detection. A significantly higher proportion of respondents from ODs with high childhood TB case detection had a good attitude (98.96 vs. 97.08%, p = 0.002) and performed good practices (58.55 vs. 45.26%, p = 0.02) on contact investigation in the community than those from low childhood TB case detection ODs.

CONCLUSIONS

Healthcare providers from ODs with high childhood TB detection had better attitudes and practices towards childhood TB. The attitudes and practices need to be improved among healthcare providers in ODs with low case detection. Further investment in training and experience sharing on childhood TB case detection among healthcare providers is needed to improve childhood TB case detection.

Theory-Informed Design of a Tailored Strategy for Implementing Household TB Contact Investigation in Uganda

Since 2012, the World Health Organization has recommended household contact investigation as an evidence-based intervention to find and treat individuals with active tuberculosis (TB), the most common infectious cause of death worldwide after COVID-19. Unfortunately, uptake of this recommendation has been suboptimal in low- and middle-income countries, where the majority of affected individuals reside, and little is known about how to effectively deliver this service. Therefore, we undertook a systematic process to design a novel, theory-informed implementation strategy to promote uptake of contact investigation in Uganda, using the COM-B (Capability-Opportunity-Motivation-Behavior) model and the Behavior Change Wheel (BCW) framework. We systematically engaged national, clinic-, and community-based stakeholders and collectively re-examined the results of our own formative, parallel mixed-methods studies. We identified three core behaviors within contact investigation that we wished to change, and multiple antecedents (i.e., barriers and facilitators) of those behaviors. The BCW framework helped identify multiple intervention functions targeted to these antecedents, as well as several policies that could potentially enhance the effectiveness of those interventions. Finally, we identified multiple behavior change techniques and policies that we incorporated into a multi-component implementation strategy, which we compared to usual care in a household cluster-randomized trial. We introduced some components in both arms, including those designed to facilitate initial uptake of contact investigation, with improvement relative to historical controls. Other components that we introduced to facilitate completion of TB evaluation—home-based TB-HIV evaluation and follow-up text messaging—returned negative results due to implementation failures. In summary, the Behavior Change Wheel framework provided a feasible and transparent approach to designing a theory-informed implementation strategy. Future studies should explore the use of experimental methods such as micro-randomized trials to identify the most active components of implementation strategies, as well as more creative and entrepreneurial methods such as human-centered design to better adapt the forms and fit of implementation strategies to end users.

Estimating the long-term effects of mass screening for latent and active tuberculosis in the Marshall Islands

BACKGROUND

Ambitious population-based screening programmes for latent and active tuberculosis (TB) were implemented in the Republic of the Marshall Islands in 2017 and 2018.

METHODS

We used a transmission dynamic model of TB informed by local data to capture the Marshall Islands epidemic's historical dynamics. We then used the model to project the future epidemic trajectory following the active screening interventions, as well as considering a counterfactual scenario with no intervention. We also simulated future scenarios including periodic interventions similar to those previously implemented, to assess their ability to reach the End TB Strategy targets and TB pre-elimination in the Marshall Islands.

RESULTS

The screening activities conducted in 2017 and 2018 were estimated to have reduced TB incidence and mortality by around one-third in 2020, and are predicted to achieve the End TB Strategy milestone of 50% incidence reduction by 2025 compared with 2015. Screening interventions had a considerably greater impact when latent TB screening and treatment were included, compared with active case finding alone. Such combined programmes implemented at the national level could achieve TB pre-elimination around 2040 if repeated every 2 years.

CONCLUSIONS

Our model suggests that it would be possible to achieve TB pre-elimination by 2040 in the Marshall Islands through frequent repetition of the same interventions as those already implemented in the country. It also highlights the importance of including latent infection testing in active screening activities.

The role of counselling in tuberculosis diagnostic evaluation and contact tracing: scoping review and stakeholder consultation of knowledge and research gaps

Background

Tuberculosis (TB) care cascade analyses show large gaps at early stages, including care-seeking and diagnostic evaluation, where promising interventions to decrease attrition are urgently needed. Person-centered care is prioritized in the World Health Organization’s End TB strategy; yet little is known about how it is delivered and can be optimized. Recommendations for counselling, a core component of person-centered care, are largely limited to its role in improving TB treatment adherence. The role of counselling to close key diagnostic gaps in the care cascade is poorly understood.

Methods

We conducted a scoping review to identify evidence on the use of counselling at TB diagnosis, for both people with presumptive TB and index patients to promote patient retention and contact tracing. Using search terms for TB, diagnosis and counselling, we systematically searched PubMed, EMBASE and Web of Science. Two independent reviewers screened all abstracts, full-texts, extracted data and conducted a quality assessment. We used thematic analysis to identify key themes.

Results

After screening 1785 articles, we extracted data from 15 studies and determined that the major themes best corresponded to the following gaps in the TB care cascade: care-seeking, pre-diagnosis, and pre-treatment. Studies were conducted across varied settings including pharmacies, primary health centres, and clinics, primarily in high TB incidence countries. No study directly evaluated the impact of counselling on outcomes such as treatment initiation or retention in care. Included studies suggested counselling may play an important role in improving the uptake of diagnostic testing and contact tracing. Barriers to counselling included time and personnel requirements. Stakeholder consultation emphasized the importance of high-quality counselling as a core tenet of TB care.

Conclusion

Data on the impact of counselling to improve TB case detection are absent from the literature. The shift towards person-centred care for TB presents an opportunity to incorporate counselling during earlier stages of the TB care cascade; however, evidence-based approaches are needed. Implementation research is needed to operationalize and evaluate counselling to strengthen high-quality TB care delivery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12556-8.

Tuberculosis infection among youths in overcrowded university hostels in Kenya: a cross-sectional study

Background

Tuberculosis (TB) remains a top global health problem and its transmission rate among contacts is higher when they are cohabiting with a person who is sputum smear-positive. Our study aimed to describe the prevalence of TB among student contacts in the university and determine factors associated with TB transmission.

Methods

We performed a cross-sectional study with an active contact case finding approach among students receiving treatment at Kilifi County Hospital from January 2016 to December 2017. The study was conducted in a public university in Kilifi County, a rural area within the resource-limited context of Kenya. The study population included students attending the university and identified as sharing accommodation or off-campus hostels, or a close social contact to an index case. The index case was defined as a fellow university student diagnosed with TB at the Kilifi County Hospital during the study period. Contacts were traced and tested for TB using GeneXpert.

Results

Among the 57 eligible index students identified, 51 (89%) agreed to participate. A total of 156 student contacts were recruited, screened and provided a sputum sample. The prevalence of TB (GeneXpert test positive/clinical diagnosis) among all contacts was 8.3% (95% CI 4.5–14%). Among the 8.3% testing positive 3.2% (95% CI 1.0–7.3%) were positive for GeneXpert only. Sharing a bed with an index case was the only factor significantly associated with TB infection. No other demographic or clinical factor was associated with TB infection.

Conclusion

Our study identified a high level of TB transmission among university students who had contact with the index cases. The study justifies further research to explore the genetic sequence and magnitude of TB transmission among students in overcrowded university in resource limited contexts.

Household contact tracing with intensified tuberculosis and HIV screening in South Africa: a cluster randomised trial

Background

Household contact tracing for tuberculosis (TB) may facilitate diagnosis and access to TB preventive treatment (TPT). We investigated whether household contact tracing and intensive TB/human immunodeficiency virus (HIV) screening would improve TB-free survival.

Methods

Household contacts of index TB patients in 2 South African provinces were randomized to home tracing and intensive HIV/TB screening or standard of care (SOC; clinic referral letters). The primary outcome was incident TB or death at 15 months. Secondary outcomes included tuberculin skin test (TST) positivity in children ≤14 years and undiagnosed HIV.

Results

From December 2016 through March 2019, 1032 index patients (4459 contacts) and 1030 (4129 contacts) were randomized to the intervention and SOC arms. Of intervention arm contacts, 3.2% (69 of 2166) had prevalent microbiologically confirmed TB. At 15 months, the cumulative incidence of TB or death did not differ between the intensive screening (93 of 3230, 2.9%) and SOC (80 of 2600, 3.1%) arms (hazard ratio, 0.90; 95% confidence interval [CI], .66–1.24). TST positivity was higher in the intensive screening arm (38 of 845, 4.5%) compared with the SOC arm (15 of 800, 1.9%; odds ratio, 2.25; 95% CI, 1.07–4.72). Undiagnosed HIV was similar between arms (41 of 3185, 1.3% vs 32 of 2543, 1.3%; odds ratio, 1.02; 95% CI, .64–1.64).

Conclusions

Household contact tracing with intensive screening and referral did not reduce incident TB or death. Providing referral letters to household contacts of index patients is an alternative strategy to home visits.

Clinical Trials Registration

ISRCTN16006202.

Estimating the population at high risk for tuberculosis through household exposure in high-incidence countries: a model-based analysis

BACKGROUND

Household contacts of people with pulmonary tuberculosis (TB) have greater risk of developing TB. Recent guidelines conditionally recommended TB preventive treatment (TPT) for household contacts of any age living in TB high-incidence countries, expanding earlier guidance to provide TPT to household contacts under five. The all-age population of household contacts has not been estimated.

METHODS

Our model-based estimation included 20 countries with >80% of incident TB globally in 2019. We developed country-specific distributions of household composition by age and sex using bootstrap resampling from health surveys and census data. We incorporated age-, sex-, year-, and location-specific estimates of pulmonary TB incidence from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 to estimate the population in each country sharing a household with someone with incident pulmonary TB, and quantified uncertainty using a Monte Carlo approach.

FINDINGS

We estimate that 38 million [95% uncertainty interval (UI) 33- 43 million] individuals lived in a household with someone with incident pulmonary TB in 2019 in these 20 countries. Children under five made up 12% of the population with household exposure, while adults were 65%. Zimbabwe, Mozambique, Zambia, and Pakistan had the highest proportion of the population with household exposure, while India had the highest number of contacts (11·4 million, 95% UI 9·7-13·4 million).

INTERPRETATION

Expanding TPT evaluation to household contacts of all ages in high-incidence countries could include a population more than 7-times larger than the under-5 contacts previously prioritized. This would substantially increase the impact of household contact investigation on reducing TB morbidity and mortality.

FUNDING

JMR is supported by the National Institute of Allergy and Infectious Diseases (K01 AI138620). This research was funded in part by a 2020 developmental grant from the University of Washington / Fred Hutch Center for AIDS Research, an NIH funded program under award number AI027757 which is supported by the following NIH Institutes and Centers: NIAID, NCI, NIMH, NIDA, NICHD, NHLBI, NIA, NIGMS, NIDDK. This work was funded in part by the National Science Foundation (DMS-1839116).

Symptom-based Screening Versus Chest Radiography for TB Child Contacts: A Systematic Review and Meta-analysis

BACKGROUND

Accessibility to chest radiography remains a major challenge in high burden and low-income countries. The World Health Organization (WHO) guidelines acknowledge that for child contacts under 5 years, a negative symptom-based screening is sufficient to exclude active tuberculosis (TB), but in child contacts older than 5 years, a chest radiograph should be considered. We performed a systematic review and meta-analysis to assess the performance of symptom-based screening compared with chest radiography in household contacts under 15 years in low-income and middle-income countries.

METHODS

Screening articles published prior 1 October 2020 and data extraction were performed by 2 independent reviewers. The primary outcome was the concordance between symptom screening and chest radiography using the prevalence adjusted bias adjusted kappa coefficient (PABAK) and the proportion of asymptomatic children with negative chest radiography. The analysis was stratified by age group.

RESULTS

Of 639 identified articles, 10 were included. PABAK varied between 0.09 and 0.97 and between 0.22 and 0.98, in children less than 5 years and 5-14 years, respectively. The pooled proportion of children with both non-TB suggestive symptoms and chest radiography findings was 98.7% (96.9-99.8) in children less than 5 years and 98.1% (93.8-100) in children of age 5-14 years.

CONCLUSIONS

Despite low concordance between symptom-based screening and chest radiography, most children without TB suggestive symptoms did not have chest radiography findings suggestive of TB. These results suggest that a negative symptom screening is sufficient to rule out active TB, supporting the WHO recommendation to use symptom-based screening alone when chest radiography is not available.

The impact of active case finding on transmission dynamics of tuberculosis: A modelling study

Background

In the last decade, active case finding (ACF) strategies for tuberculosis (TB) have been implemented in many diverse settings, with some showing large increases in case detection and reporting at the sub-national level. There have also been several studies which seek to provide evidence for the benefits of ACF to individuals and communities in the broader context. However, there remains no quantification of the impact of ACF with regards to reducing the burden of transmission. We sought to address this knowledge gap and quantify the potential impact of active case finding on reducing transmission of TB at the national scale and further, to determine the intensification of intervention efforts required to bring the reproduction number (R₀) below 1 for TB.

Methods

We adopt a dynamic transmission model that incorporates heterogeneity in risk to TB to assess the impact of an ACF programme (IMPACT TB) on reducing TB incidence in Vietnam and Nepal. We fit the models to country-level incidence data using a Bayesian Markov Chain Monte Carlo approach. We assess the impact of ACF using a parameter in our model, which we term the treatment success rate. Using programmatic data, we estimate how much this parameter has increased as a result of IMPACT TB in the implementation districts of Vietnam and Nepal and quantify additional efforts needed to eliminate transmission of TB in these countries by 2035.

Results

Extending the IMPACT TB programme to national coverage would lead to moderate decreases in TB incidence and would not be enough to interrupt transmission by 2035. Decreasing transmission sufficiently to bring the reproduction number (R0) below 1, would require a further intensification of current efforts, even at the sub-national level.

Conclusions

Active case finding programmes are effective in reducing TB in the short term. However, interruption of transmission in high-burden countries, like Vietnam and Nepal, will require comprehensive incremental efforts. Complementary measures to reduce progression from infection to disease, and reactivation of latent infection, are needed to meet the WHO End TB incidence targets.

Cost-effectiveness of household contact investigation for detection of tuberculosis in Pakistan

OBJECTIVES

Despite WHO guidelines recommending household contact investigation, and studies showing the impact of active screening, most tuberculosis (TB) programmes in resource-limited settings only carry out passive contact investigation. The cost of such strategies is often cited as barriers to their implementation. However, little data are available for the additional costs required to implement this strategy. We aimed to estimate the cost and cost-effectiveness of active contact investigation as compared with passive contact investigation in urban Pakistan.

METHODS

We estimated the cost-effectiveness of 'enhanced' (passive with follow-up) and 'active' (household visit) contact investigations compared with standard 'passive' contact investigation from providers and the programme's perspective using a simple decision tree. Costs were collected in Pakistan from a TB clinic performing passive contact investigation and from studies of active contact tracing interventions conducted. The effectiveness was based on the number of patients with TB identified among household contacts screened.

RESULTS

The addition of enhanced contact investigation to the existing passive mode detected 3.8 times more cases of TB per index patient compared with passive contact investigation alone. The incremental cost was US$30 per index patient, which yielded an incremental cost of US$120 per incremental patient identified with TB. The active contact investigation was 1.5 times more effective than enhanced contact investigation with an incremental cost of US$238 per incremental patient with TB identified.

CONCLUSION

Our results show that enhanced and active approaches to contact investigation effectively identify additional patients with TB among household contacts at a relatively modest cost. These strategies can be added to the passive contact investigation in a high burden setting to find the people with TB who are missed and meet the End TB strategy goals.

Socio-protective effects of active case finding on catastrophic costs from tuberculosis in Ho Chi Minh City, Viet Nam: a longitudinal patient cost survey

BACKGROUND

Many tuberculosis (TB) patients incur catastrophic costs. Active case finding (ACF) may have socio-protective properties that could contribute to the WHO End TB Strategy target of zero TB-affected families suffering catastrophic costs, but available evidence remains limited. This study measured catastrophic cost incurrence and socioeconomic impact of an episode of TB and compared those socioeconomic burdens in patients detected by ACF versus passive case finding (PCF).

METHODS

This cross-sectional study fielded a longitudinal adaptation of the WHO TB patient cost survey alongside an ACF intervention from March 2018 to March 2019. The study was conducted in six intervention (ACF) districts and six comparison (PCF) districts of Ho Chi Minh City, Viet Nam. Fifty-two TB patients detected through ACF and 46 TB patients in the PCF cohort were surveyed within two weeks of treatment initiation, at the end of the intensive phase of treatment, and after treatment concluded. The survey measured income, direct and indirect costs, and socioeconomic impact based on which we calculated catastrophic cost as the primary outcome. Local currency was converted into US$ using the average exchange rates reported by OANDA for the study period (VNĐ1 = US$0.0000436, 2018-2019). We fitted logistic regressions for comparisons between the ACF and PCF cohorts as the primary exposures and used generalized estimating equations to adjust for autocorrelation.

RESULTS

ACF patients were poorer than PCF patients (multidimensional poverty ratio: 16 % vs. 7 %; p = 0.033), but incurred lower median pre-treatment costs (US$18 vs. US$80; p < 0.001) and lower median total costs (US$279 vs. US$894; p < 0.001). Fewer ACF patients incurred catastrophic costs (15 % vs. 30 %) and had lower odds of catastrophic cost (aOR = 0.17; 95 % CI: [0.05, 0.67]; p = 0.011), especially during the intensive phase (OR = 0.32; 95 % CI: [0.12, 0.90]; p = 0.030). ACF patient experienced less social exclusion (OR = 0.41; 95 % CI: [0.18, 0.91]; p = 0.030), but more often resorted to financial coping mechanisms (OR = 5.12; 95 % CI: [1.73, 15.14]; p = 0.003).

CONCLUSIONS

ACF can be effective in reaching vulnerable populations and mitigating the socioeconomic burden of TB, and can contribute to achieving the WHO End TB Strategy goals. Nevertheless, as TB remains a catastrophic life event, social protection efforts must extend beyond ACF.

Does tuberculosis screening improve individual outcomes? A systematic review

BACKGROUND

To determine if tuberculosis (TB) screening improves patient outcomes, we conducted two systematic reviews to investigate the effect of TB screening on diagnosis, treatment outcomes, deaths (clinical review assessing 23 outcome indicators); and patient costs (economic review).

METHODS

Pubmed, EMBASE, Scopus and the Cochrane Library were searched between 1/1/1980-13/4/2020 (clinical review) and 1/1/2010-14/8/2020 (economic review). As studies were heterogeneous, data synthesis was narrative.

FINDINGS

Clinical review: of 27,270 articles, 18 (n=3 trials) were eligible. Nine involved general populations. Compared to passive case finding (PCF), studies showed lower smear grade (n=2/3) and time to diagnosis (n=2/3); higher pre-treatment losses to follow-up (screened 23% and 29% vs PCF 15% and 14%; n=2/2); and similar treatment success (range 68-81%; n=4) and case fatality (range 3-11%; n=5) in the screened group. Nine reported on risk groups. Compared to PCF, studies showed lower smear positivity among those culture-confirmed (n=3/4) and time to diagnosis (n=2/2); and similar (range 80-90%; n=2/2) treatment success in the screened group. Case fatality was lower in n=2/3 observational studies; both reported on established screening programmes. A neonatal trial and post-hoc analysis of a household contacts trial found screening was associated with lower all-cause mortality. Economic review: From 2841 articles, six observational studies were eligible. Total costs (n=6) and catastrophic cost prevalence (n=4; range screened 9-45% vs PCF 12-61%) was lower among those screened.

INTERPRETATION

We found very limited patient outcome data. Collecting and reporting this data must be prioritised to inform policy and practice.

FUNDING

WHO and EDCTP.

The yield of tuberculosis contact investigation in low- and middle-income settings: a systematic review and meta-analysis

Background

Contact investigation, the systematic evaluation of individuals in close contact with an infectious tuberculosis (TB) patient, is a key active case-finding strategy for global TB control. Better estimates of the yield of contact investigation can guide strategies to reduce the number of underreported and underdiagnosed TB cases, approximately three million cases per year globally. A systematic review (Prospero ID # CRD42019133380) and meta-analysis was conducted to update and enhance the estimates of the yield of TB contact investigation in low- and middle-income countries (LMIC). Pubmed, Web of Science, Embase and the WHO Global Index Medicus were searched for peer-reviewed studies (published between January 2006–April 2019); studies reporting the number of active TB or latent tuberculosis infection (LTBI) found through contact investigation were included. Pooled data were meta-analyzed using a random effects model and risk of bias was assessed.

Results

Of 1,644 unique citations obtained from database searches, 110 studies met eligibility criteria for descriptive data synthesis and 95 for meta-analysis. The pooled yields of contact investigation activities for different outcomes were: secondary cases of all active TB (defined as those bacteriologically confirmed or clinically diagnosed) 2.87% (2.61–3.14, I² 97.79%), bacteriologically confirmed active TB 2.04% (1.77–2.31, I² 98.06%), and LTBI 43.83% (38.11–49.55, I² 99.36%). Yields are interpreted as the percent of contacts screened who are diagnosed with active TB as a result of TB contact investigation activities. Pooled estimates were substantially heterogenous (I² ≥ 75%).

Conclusions

This study provides methodologically rigorous and up-to-date estimates for the yield of TB contact investigation activities in low- and middle-income countries (LMIC). While the data are heterogenous, these findings can inform strategic and programmatic planning for scale up of TB contact investigation activities.

Challenges Perceived by Health Care Providers for Implementation of Contact Screening and Isoniazid Chemoprophylaxis in Karnataka, India

Background: In India, challenges in pediatric TB contact screening and chemoprophylaxis initiation are still underexplored. Elucidating these challenges will help in better implementation of the programme at the grass-roots level thereby helping in early detection of pediatric cases and timely initiation of preventive therapy. This study aimed at exploring the challenges faced by the health care provider in contact screening and chemoprophylaxis initiation implementation of the pediatric household contacts. Methods: A qualitative study was conducted in the districts of Bengaluru and Udupi and in-depth interviews of key participants were adopted to explore the challenges. Qualitative data analysis was done after developing transcripts by generating themes and codes. Results: The key challenges were identified as stigma towards the disease, migrant patients with changing address, difficulty in sample collection, anxiety among parents due to long duration of the prophylactic treatment and adherence to IPT is not well documented, inadequate transportation from rural areas, and the ongoing COVID-19 pandemic. Conclusions: It is important for the National TB programme to address these challenges efficiently and effectively. Innovative solutions, feasible engagements, and massive efforts are to be taken by the programme to improve contact screening and isoniazid chemoprophylaxis implementation.

The knowns and unknowns of latent Mycobacterium tuberculosis infection

Humans have been infected with Mycobacterium tuberculosis (Mtb) for thousands of years. While tuberculosis (TB), one of the deadliest infectious diseases, is caused by uncontrolled Mtb infection, over 90% of presumed infected individuals remain asymptomatic and contain Mtb in a latent TB infection (LTBI) without ever developing disease, and some may clear the infection. A small number of heavily Mtb-exposed individuals appear to resist developing traditional LTBI. Because Mtb has mechanisms for intracellular survival and immune evasion, successful control involves all of the arms of the immune system. Here, we focus on immune responses to Mtb in humans and nonhuman primates and discuss new concepts and outline major knowledge gaps in our understanding of LTBI, ranging from the earliest events of exposure and infection to success or failure of Mtb control.