6-month versus 36-month isoniazid preventive treatment for tuberculosis in adults with HIV infection in Botswana: a randomised, double-blind, placebo-controlled trial

Risk of tuberculosis after initiation of antiretroviral therapy among persons with HIV in Europe

OBJECTIVES

Tuberculosis (TB) risk after initiation of antiretroviral treatment (ART) is not well described in a European setting, with an average TB incidence of 25/105 in the background population.

METHODS

We included all adult persons with HIV starting ART in the RESPOND cohort between 2012 and 2020. TB incidence rates (IR) were assessed for consecutive time intervals post-ART initiation. Risk factors for TB within 6 months from ART initiation were evaluated using Poisson regression models.

RESULTS

Among 8441 persons with HIV, who started ART, 66 developed TB during 34,239 person-years of follow-up (PYFU), corresponding to 1.87/1000 PYFU (95% confidence interval [CI]: 1.47-2.37). TB IR was highest in the first 3 months after ART initiation (14.41/1000 PY (95%CI 10.08-20.61]) and declined at 3-6, 6-12, and >12 months post-ART initiation (5.89 [95%CI 3.35-10.37], 2.54 [95%CI 1.36-4.73] and 0.51 [95%CI 0.30-0.86]), respectively. Independent risk factors for TB within the first 6 months after ART initiation included follow-up in Northern or Eastern Europe region, African origin, baseline CD4 count <200 cells/mm3, HIV RNA >100,000 copies/mL, injecting drug use and heterosexual transmission.

CONCLUSIONS

TB IR was highest in the first 3 months post-ART initiation and was associated with baseline risk factors, highlighting the importance of thorough TB risk assessment at ART initiation.

Effectiveness of preventive treatment among different age groups and Mycobacterium tuberculosis infection status: a systematic review and individual-participant data meta-analysis of contact tracing studies

BACKGROUND

Tuberculosis is a preventable disease. However, there is debate regarding which individuals would benefit most from tuberculosis preventive treatment and whether these benefits vary in settings with a high burden and low burden of tuberculosis. We aimed to compare the effectiveness of tuberculosis preventive treatment in exposed individuals of differing ages and Mycobacterium tuberculosis infection status while considering tuberculosis burden of the settings.

METHODS

In this systematic review and individual-participant meta-analysis, we investigated the development of incident tuberculosis in people closely exposed to individuals with tuberculosis. We searched for studies published between Jan 1, 1998, and April 6, 2018, in MEDLINE, Web of Science, BIOSIS, and Embase. We restricted our search to cohort studies; case-control studies and outbreak reports were excluded. Two reviewers evaluated titles, abstracts, and full text articles for eligibility. At each stage, two reviewers discussed discrepancies and re-evaluated articles until a consensus was reached. Individual-participant data and a pre-specified list of variables, including characteristics of the exposed contact, the index patient, and environmental characteristics, were requested from authors of all eligible studies; contacts exposed to a drug-resistant tuberculosis index patient were excluded. The primary study outcome was incident tuberculosis. We estimated adjusted hazard ratios (aHRs) for incident tuberculosis with mixed-effects Cox regression models with a study-level random effect. We estimated the number-needed-to-treat (NNT) to prevent one person developing tuberculosis. Propensity score matching procedures were used in all analyses. This study is registered with PROSPERO (CRD42018087022).

FINDINGS

After screening 25 358 records for eligibility, 439 644 participants from 32 cohort studies were included in the individual-participant data meta-analysis. Participants were followed for 1 396 413 person-years (median of 2·7 years [IQR 1·3-4.4]), during which 2496 people were diagnosed with incident tuberculosis. Overall, effectiveness of preventive treatment was 49% (aHR 0·51 [95% CI 0·44-0·60]). Participants with a positive tuberculin-skin-test (TST) or IFNγ release assay (IGRA) result at baseline benefitted from greater protection, regardless of age (0·09 [0·05-0·17] in children younger than 5 years, 0·20 [0·15-0·28] in individuals aged 5-17 years, and 0·17 [0·13-0·22] in adults aged 18 years and older). The effectiveness of preventive treatment was greater in high-burden (0·31 [0·23-0·40]) versus low-burden (0·58 [0·47-0·72]) settings. The NNT ranged from 9 to 34 depending on age among participants with a positive TST or IGRA in both high-burden and low-burden settings; among all contacts (regardless of TST or IGRA test result), the NNT ranged from 29 to 43 in high-burden settings and 213 to 455 in low-burden settings.

INTERPRETATION

Our findings suggest that a risk-targeted strategy prioritising contacts with evidence of M tuberculosis infection might be indicated in low-burden settings, and a broad approach including all contacts should be considered in high-burden settings. Preventive treatment was similarly effective among contacts of all ages.

FUNDING

None.

Long-Term Protective Effect of Tuberculosis Preventive Therapy in a Medium/High Tuberculosis Incidence Setting

BACKGROUND

The duration of the protective effect of tuberculosis preventive therapy (TPT) is controversial. Some studies have found that the protective effect of TPT is lost after cessation of therapy among people with human immunodeficiency virus (HIV) in settings with very high tuberculosis incidence, but others have found long-term protection in low-incidence settings.

METHODS

We estimated the incidence rate (IR) of new tuberculosis disease for up to 12 years after randomization to 4 months of rifampin or 9 months of isoniazid, among 991 Brazilian participants in a TPT trial in the state of Rio de Janeiro, with an incidence of 68.6/100 000 population in 2022. The adjusted hazard ratios (aHRs) of independent variables for incident tuberculosis were calculated.

RESULTS

The overall tuberculosis IR was 1.7 (95% confidence interval [CI], 1.01- 2.7) per 1000 person-years (PY). The tuberculosis IR was higher among those who did not complete TPT than in those who did (2.9 [95% CI, 1.3-5.6] vs 1.1 [.4-2.3] per 1000 PY; IR ratio, 2.7 [1.0-7.2]). The tuberculosis IR was higher within 28 months after randomization (IR, 3.5 [95% CI, 1.6-6.6] vs 1.1 [.5-2.1] per 1000 PY between 28 and 143 months; IR ratio, 3.1 [1.2-8.2]). Treatment noncompletion was the only variable associated with incident tuberculosis (aHR, 3.2 [95% CI, 1.1-9.7]).

CONCLUSIONS

In a mostly HIV-noninfected population, a complete course of TPT conferred long-term protection against tuberculosis.

One-Pot Assembly of Mannose-Capped Lipoarabinomannan Motifs up to 101-Mer from the Mycobacterium tuberculosis Cell Wall

Lipoarabinomannan (LAM) from the Mycobacterium tuberculosis cell envelope represents important targets for the development of new therapeutic agents against tuberculosis, which is a deadly disease that has plagued mankind for a long time. However, the accessibility of long, branched, and complex lipoarabinomannan over 100-mer remains a long-standing challenge. Herein, we report the modular synthesis of mannose-capped lipoarabinomannan 101-mer from the M. tuberculosis cell wall using a one-pot assembly strategy on the basis of glycosyl ortho-(1-phenylvinyl)benzoates (PVB), which not only accelerates the modular synthesis but also precludes the potential problems associated with one-pot glycosylation with thioglycosides. Shorter sequences including 18-mer, 19-mer, and 27-mer are also synthesized for in-depth structure-activity relationship biological studies. Current synthetic routes also highlight the following features: (1) streamlined synthesis of various linear and branched glycans using one-pot orthogonal glycosylation on the combination of glycosyl N-phenyltrifluoroacetimidates, glycosyl ortho-alkynylbenzoates, and glycosyl PVB; (2) highly stereoselective construction of 10 1,2-cis-arabinofuranosyl linkages using 5-O-(2-quinolinecarbonyl)-directing 1,2-cis-arabinofuranosylation via a hydrogen-bond-mediated aglycone delivery strategy; and (3) convergent [(18 + 19) × 2 + 27] one-pot synthesis of the 101-mer LAM polysaccharide. The present work demonstrates that this orthogonal one-pot glycosylation strategy can highly streamline the chemical synthesis of long, branched, and complex polysaccharides.

Completion of isoniazid preventive therapy for latent tuberculosis infection among children and adolescents compared to adults living with HIV in Kinshasa, Democratic Republic of the Congo

BACKGROUND

Little is known about isoniazid preventive therapy (IPT) completion rates among children or adolescents compared to adults living with HIV in Kinshasa, Democratic Republic of the Congo (DRC).

METHODS

We conducted a retrospective cohort analysis including children, adolescents, and adults living with HIV who were treated at FHI360 and partners-implemented HIV care programs at six health zones in Kinshasa, DRC, from 2004 to 2020. The primary outcome was the proportion of children, adolescents versus adults who did complete 6 months of daily self-administered IPT. Log-binomial regression assessed independent predictors of IPT non-completion and Kaplan-Meier technique for survival analysis.

RESULTS

Of 11,691 eligible patients on ART who initiated IPT, 429 were children (<11 years), 804 adolescents (11-19 years), and 10,458 adults (≥20 years). The median age was 7 (IQR: 3-9) years for children, 15 (IQR: 13-17) years for adolescents, and 43 (35-51) years for adults. Among those who were initiated on IPT, 5625 out of 11,691 people living with HIV (PLHIV) had IPT completion outcome results, and an overall 3457/5625 (61.5%) completion rate was documented. Compared to adults, children and adolescents were less likely to complete IPT [104/199 (52.3%) and 268/525 (51.0%), respectively, vs. 3085/4901 (62.9%)]. After adjustment, the only independent predictors for IPT non-completion were health zone of residence and type of ART regimen. Kaplan-Meier analysis showed comparable poor survival among patients who completed IPT versus those who did not (p-value for log-rank test, 0.15).

CONCLUSIONS

The overall sub-optimal IPT completion rate in adults as well as children/adolescents in this setting is of great concern. Prospective studies are needed to elucidate the specific barriers to IPT completion among children, adolescents, and adults in DRC as well as the scale-up of evidence-informed interventions to improve IPT completion, such as adoption of shorter TB preventive regimens.

Situation Analysis of Early Implementation of Programmatic Management of Tuberculosis Preventive Treatment among Household Contacts of Pulmonary TB Patients in Delhi, India

Tuberculosis Preventive Treatment (TPT) is a powerful tool for preventing the TB infection from developing into active TB disease, and has recently been expanded to all household contacts of TB cases in India. This study employs a mixed-methods approach to conduct a situational analysis of the initial phase of TPT implementation among household contacts of pulmonary TB patients in three districts of Delhi, India. It was completed using a checklist based assessments, care cascade data, and qualitative analysis. Our observations indicated that organizational structure and planning were established, but implementation of TPT was suboptimal with issues in drug availability and procurement, budget, human resources, and training. Awareness and motivation, and shorter regimen, telephonic assessment, and collaboration with NGOs emerged as enablers. Apprehension about taking TPT, erratic drug supply, long duration of treatment, side effects, overburden, large population, INH resistance, data entry issues, and private provider reluctance emerged as barriers. The study revealed potential solutions for optimizing TPT implementation. It is evident that, while progress has been made in TPT implementation, there is room for improvement and refinement across various domains.

Preventive treatment for latent tuberculosis from Indian perspective

The persistent morbidity and mortality associated with tuberculosis (TB), despite our continued efforts, has been long recognized, and the rise in the incidence of drug-resistant TB adds to the preexisting concern. The bulk of the TB burden is confined to low-income countries, and rigorous efforts are made to detect, notify, and systematically treat TB. Efforts have been infused with renewed vigor and determination by the World Health Organization (WHO) to eliminate tuberculosis in the near future. Different health agencies worldwide are harvesting all possible strategies apart from consolidating ongoing practices, including prevention of the development of active disease by treating latent TB infection (LTBI). The guidelines for the same were already provided by the WHO and were then adapted in the Indian guidelines for the treatment of LTBI in 2021. While the long-term impact of TBI treatment is awaited, in this article, we aim to discuss the implications in the Indian context.

Prioritizing persons deprived of liberty in global guidelines for tuberculosis preventive treatment

In this Policy Forum piece, Aditya Narayan and colleagues discuss the challenges and opportunities for tuberculosis preventive treatment in carceral settings.

Efficacy and Safety of Different Drug Regimens for Tuberculosis Preventive Treatment: A Systematic Review and Meta-Analysis

Tuberculosis prevention treatment (TPT) is crucial to the eradication of tuberculosis (TB). Through a comprehensive review and meta-analysis, we compared the efficacy and safety of different TPT regimens. We searched PubMed, Google Scholar, and medrxiv.org with search terms Tuberculosis Preventive Treatment, TPT, efficacy, safety, and drug regimens for TPT and all RCT, irrespective of age, setting, or co-morbidities, comparing at least one TPT regimen to placebo, no therapy, or other TPT regimens were screened and those reporting either efficacy or safety or both were included. The meta-analysis data were synthesized with Review Manager and the risk ratio (RR) was calculated. Out of 4465 search items, 15 RCTs (randomized-controlled trials) were included. The TB infection rate was 82/6308 patients in the rifamycin plus isoniazid group (HR) as compared to 90/6049 in the isoniazid monotherapy (H) group (RR: 0.89 (95% CI: 0.66, 1.19; p=0.43). A total of 965/6478 vs 1065/6219 adverse drug reactions (ADRs) occurred in HR and H groups respectively (RR: 0.86 (95%CI: 0.80 0.93); P<0.0001). Efficacy analysis of the rifampicin plus pyrazinamide (RZ) vs H showed that the risk ratio of infection rate was not considerably varied (RR: 0.97 (95% CI: 0.47, 2.03); P=0.94). Safety analysis showed in 229/572 patients developed ADRs in rifampicin plus pyrazinamide as compared to 129/600 ADRs in the isoniazid group. (RR: 1.87 (95% CI: 1.44, 2.43)). Safety analysis of only rifamycin (R) vs H group showed 23/718 ADRs in R vs 57/718 ADRs in H group (RR: 0.40 (95% CI: 0.25 0.65); P=0.0002). Rifamycin plus isoniazid (3HP/R) has no edge over other regimens in terms of efficacy but this regimen was found significantly safer as compared to any other regimens used for TPT. Rifampicin plus pyrazinamide (RZ) was found equally efficacious but less safe as compared to other regimens.

Landscape of TB Infection and Prevention among People Living with HIV

Tuberculosis (TB) is one of the leading causes of mortality in people living with HIV (PLHIV) and contributes to up to a third of deaths in this population. The World Health Organization guidelines aim to target early detection and treatment of TB among PLHIV, particularly in high-prevalence and low-resource settings. Prevention plays a key role in the fight against TB among PLHIV. This review explores TB screening tools available for PLHIV, including symptom-based screening, chest radiography, tuberculin skin tests, interferon gamma release assays, and serum biomarkers. We then review TB Preventive Treatment (TPT), shown to reduce the progression to active TB and mortality among PLHIV, and available TPT regimens. Last, we highlight policy-practice gaps and barriers to implementation as well as ongoing research needs to lower the burden of TB and HIV coinfection through preventive activities, innovative diagnostic tests, and cost-effectiveness studies.

Evidence for Implementation: Management of TB in HIV and Pregnancy

PURPOSE OF REVIEW

Pregnant people living with HIV (PLWH) are at especially high risk for progression from latent tuberculosis infection (LTBI) to active tuberculosis (TB) disease. Among pregnant PLWH, concurrent TB increases the risk of complications such as preeclampsia, intrauterine fetal-growth restriction, low birth weight, preterm-delivery, perinatal transmission of HIV, and admission to the neonatal intensive care unit. The grave impact of superimposed TB disease on maternal morbidity and mortality among PLWH necessitates clear guidelines for concomitant therapy and an understanding of the pharmacokinetics (PK) and potential drug-drug interactions (DDIs) between antitubercular (anti-TB) agents and antiretroviral therapy (ART) in pregnancy.

RECENT FINDINGS

This review discusses the currently available evidence on the use of anti-TB agents in pregnant PLWH on ART. Pharmacokinetic and safety studies of anti-TB agents during pregnancy and postpartum are limited, and available data on second-line and newer anti-TB agents used in pregnancy suggest that several research gaps exist. DDIs between ART and anti-TB agents can decrease plasma concentration of ART, with the potential for perinatal transmission of HIV. Current recommendations for the treatment of LTBI, drug-susceptible TB, and multidrug-resistant TB (MDR-TB) are derived from observational studies and case reports in pregnant PLWH. While the use of isoniazid, rifamycins, and ethambutol in pregnancy and their DDIs with various ARTs are well-characterized, there is limited data on the use of pyrazinamide and several new and second-line antitubercular drugs in pregnant PLWH. Further research into treatment outcomes, PK, and safety data for anti-TB agent use during pregnancy and postpartum is urgently needed.

Testing and Scaling Interventions to Improve the Tuberculosis Infection Care Cascade

Tuberculosis (TB) preventive therapy (TPT) is increasingly recognized as the key to eliminating tuberculosis globally and is particularly critical for children with TB infection or who are in close contact with individuals with infectious TB. But many barriers currently impede successful scale-up to provide TPT to those at high risk of TB disease. The cascade of care in TB infection (and the related contact management cascade) is a conceptual framework to evaluate and improve the care of persons who are potential candidates for TPT. This review summarizes recent literature on barriers and solutions in the TB infection care cascade, focusing on children in both high- and low-burden settings, and drawing from studies on children and adults. Identifying and closing gaps in the care cascade will require the implementation of tools that are new (e.g. computer-assisted radiography) and old (e.g. efficient contact tracing), and will be aided by innovative implementation study designs, quality improvement methods, and shared clinical practice with primary care providers.

GeneXpert or chest-X-ray or tuberculin skin testing for household contact assessment (GXT): protocol for a cluster-randomized trial

Background

The World Health Organization recommends tuberculosis (TB) preventive treatment (TPT) for all people living with HIV (PLH) and household contacts (HHC) of index TB patients. Tests for TB infection (TBI) or to rule out TB disease (TBD) are preferred, but if not available, this should not be a barrier if access to these tests is limited for high-risk people, such as PLH and HHC under 5 years old. There is equipoise on the need for these tests in different risk populations, especially HHC aged over 5.

Methods

This superiority cluster-randomized multicenter trial with three arms of equal size compares, in Benin and Brazil, three strategies for HHC investigation aged 0–50: (i) tuberculin skin testing (TST) or interferon gamma release assay (IGRA) for TBI and if positive, chest X-Ray (CXR) to rule out TBD in persons with positive TST or IGRA; (ii) same as (i) but GeneXpert (GX) replaces CXR; and (iii) no TBI testing. CXR for all; if CXR is normal, TPT is recommended. All strategies start with symptom screening. Clusters are defined as HHC members of the same index patients with newly diagnosed pulmonary TBD. The main outcome is the proportion of HHC that are TPT eligible who start TPT within 3 months of the index TB patient starting TBD treatment. Societal costs, incidence of severe adverse events, and prevalence of TBD are among secondary outcomes. Stratified analyses by age (under versus over 5) and by index patient microbiological status will be conducted.

All participants provide signed informed consent. The study was approved by the Research Ethic Board of the Research Institute of the McGill University Health Centre, the Brazilian National Ethical Board CONEP, and the “Comité Local d’Éthique Pour la Recherche Biomédicale (CLERB) de l’Université de Parakou,” Benin. Findings will be submitted for publication in major medical journals and presented in conferences, to WHO and National and municipal TB programs of the involved countries.

Discussion

This randomized trial is meant to provide high-quality evidence to inform WHO recommendations on investigation of household contacts, as currently these are based on very low-quality evidence.

Trial registration

ClinicalTrials.gov NCT04528823.

Pediatric Tuberculosis Management: A Global Challenge or Breakthrough?

Managing pediatric tuberculosis (TB) remains a public health problem requiring urgent and long-lasting solutions as TB is one of the top ten causes of ill health and death in children as well as adolescents universally. Minors are particularly susceptible to this severe illness that can be fatal post-infection or even serve as reservoirs for future disease outbreaks. However, pediatric TB is the least prioritized in most health programs and optimal infection/disease control has been quite neglected for this specialized patient category, as most scientific and clinical research efforts focus on developing novel management strategies for adults. Moreover, the ongoing coronavirus pandemic has meaningfully hindered the gains and progress achieved with TB prophylaxis, therapy, diagnosis, and global eradication goals for all affected persons of varying age bands. Thus, the opening of novel research activities and opportunities that can provide more insight and create new knowledge specifically geared towards managing TB disease in this specialized group will significantly improve their well-being and longevity.

Weighted Log-Rank Test for Clinical Trials with Delayed Treatment Effect Based on a Novel Hazard Function Family

In clinical trials with delayed treatment effect, the standard log-rank method in testing the difference between survival functions may have problems, including low power and poor robustness, so the method of weighted log-rank test (WLRT) is developed to improve the test performance. In this paper, a hyperbolic-cosine-shaped (CH) hazard function family model is proposed to simulate delayed treatment effect scenarios. Then, based on Fleming and Harrington’s method, this paper derives the corresponding weight function and its regular corrections, which are powerful in test, theoretically. Alternative methods of parameters selection based on potential information are also developed. Further, the simulation study is conducted to compare the power performance between CH WLRT, classical WLRT, modest weighted log-rank test and WLRT with logistic-type weight function under different hazard scenarios and simulation settings. The results indicate that the CH statistics are powerful and robust in testing the late difference, so the CH test is useful and meaningful in practice.

Isoniazid adherence reduces mortality and incident tuberculosis at 96 weeks among adults initiating antiretroviral therapy with advanced HIV in multiple high burden settings

Background

People with human immunodeficiency virus (HIV) and advanced immunosuppression initiating antiretroviral therapy (ART) remain vulnerable to tuberculosis (TB) and early mortality. To improve early survival, isoniazid preventive therapy (IPT) or empiric TB treatment have been evaluated; however, their benefit on longer-term outcomes warrants investigation.

Methods

We present a 96-week preplanned secondary analysis among 850 ART-naive outpatients (≥13 years) enrolled in a multicountry, randomized trial of efavirenz-containing ART plus either 6-month IPT (n = 426) or empiric 4-drug TB treatment (n = 424). Inclusion criteria were CD4 count <50 cells/mm³ and no confirmed or probable TB. Death and incident TB were compared by strategy arm using the Kaplan-Meier method. The impact of self-reported adherence (calculated as the proportion of 100% adherence) was assessed using Cox-proportional hazards models.

Results

By 96 weeks, 85 deaths and 63 TB events occurred. Kaplan-Meier estimated mortality (10.1% vs 10.5%; P = .86) and time-to-death (P = .77) did not differ by arm. Empiric had higher TB risk (6.1% vs 2.7%; risk difference, −3.4% [95% confidence interval, −6.2% to −0.6%]; P = .02) and shorter time to TB (P = .02) than IPT. Tuberculosis medication adherence lowered the hazards of death by ≥23% (P < .0001) in empiric and ≥20% (P < .035) in IPT and incident TB by ≥17% (P ≤ .0324) only in IPT.

Conclusions

Empiric TB treatment offered no longer-term advantage over IPT in our population with advanced immunosuppression initiating ART. High IPT adherence significantly lowered death and TB incidence through 96 weeks, emphasizing the benefit of ART plus IPT initiation and completion, in persons with advanced HIV living in high TB-burden, resource-limited settings.

Are we underestimating the annual risk of infection with Mycobacterium tuberculosis in high-burden settings?

The annual risk of infection with Mycobacterium tuberculosis determines a population's exposure level and thus the fraction of incident tuberculosis resulting from recent infection (often considered as having occurred within the past 2 years). Contemporary annual risk of infection estimates centre around 1% in most high-burden countries. We present three arguments why these estimates-primarily derived from cross-sectional tuberculin surveys in young school children (aged 5-12 years)-might underrepresent the true annual risk of infection. First, young children are expected to have lower risk of infection than older adolescents and adults (ie, those aged 15 years and older). Second, exposure might not lead to a positive test result in some individuals. Third, cross-sectional surveys might overlook transient immune responses. Accounting for these biases, the true annual risk of infection among adults in high-burden settings is probably closer to 5-10%. Consequently, most tuberculosis in those settings should reflect infection within the past 2 years rather than remote infection occurring many years ago. Under this reframing, major reductions in tuberculosis incidence could be achievable by focusing on the minority of people who have been recently infected.

Effectiveness of a 6-Month Isoniazid on Prevention of Incident Tuberculosis Among People Living with HIV in Eritrea: A Retrospective Cohort Study

Introduction

A 6-month isoniazid as tuberculosis preventive therapy (TPT) for people living with HIV (PLHIV) was nationally introduced in Eritrea in 2014. However, its effectiveness in preventing tuberculosis (TB) and duration of protection was questioned by physicians. This study was, therefore, conducted to evaluate the impact of the isoniazid preventive therapy (IPT) primarily on the prevention of TB and duration of its protection in PLHIV.

Methods

A retrospective cohort study was conducted that selected all eligible PLHIV attending HIV care clinics in all national and regional referral hospitals in Eritrea. Data was collected from patients’ clinical cards using a structured data extraction sheet. The association between use of IPT and outcomes of interest was assessed using a Cox proportional hazard regression model and Kaplan–Meier curve.

Results

A total of 6803 patients were selected, which accounted for 75% of all PLHIV-accessing HIV care clinics in Eritrea. About 76% of patients were exposed to IPT while the remaining 24% were unexposed. The mean follow-up time was 4.9 years (SD 1.4). The incidence rate of TB was 1.7 and 10 cases per 1000 person-years in the exposed and unexposed, respectively. The unexposed had a higher risk of incident TB (adjusted hazard ratio [aHR] 3.75, 95% confidence interval [CI] 2.89, 6.13) and all-cause mortality (HR 2.41, 95% CI 1.85, 3.14) compared to the exposed. A Kaplan–Meier curve showed that the exposed group had a higher TB-free follow-up probability (98.8%) compared to the unexposed (95%) at 65 months of follow-up (p < 0.001). IPT protection decreased rapidly 6 months after isoniazid completion.

Conclusion

Use of a 6-month isoniazid as TPT was found to be effective in reducing incident TB in PLHIV-accessing HIV care clinics in Eritrea. However, the protection appeared to diminish soon, namely 6 months after completion of isoniazid, which warrants immediate attention from policy makers.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-022-00589-w.

Plasma host protein biomarkers correlating with increasing Mycobacterium tuberculosis infection activity prior to tuberculosis diagnosis in people living with HIV

BACKGROUND

Biomarkers correlating with Mycobacterium tuberculosis infection activity/burden in asymptomatic individuals are urgently needed to identify and treat those at highest risk for developing active tuberculosis (TB). Our main objective was to identify plasma host protein biomarkers that change over time prior to developing TB in people living with HIV (PLHIV).

METHODS

Using multiplex MRM-MS, we investigated host protein expressions from 2 years before until time of TB diagnosis in longitudinally collected (every 3-6 months) and stored plasma from PLHIV with incident TB, identified within a South African (SA) and US cohort. We performed temporal trend and discriminant analyses for proteins, and, to assure clinical relevance, we further compared protein levels at TB diagnosis to interferon-gamma release assay (IGRA; SA) or tuberculin-skin test (TST; US) positive and negative cohort subjects without TB. SA and US exploratory data were analyzed separately.

FINDINGS

We identified 15 proteins in the SA (n=30) and 10 in the US (n=24) incident TB subjects which both changed from 2 years prior until time of TB diagnosis after controlling for 10% false discovery rate, and were significantly different at time of TB diagnosis compared to non-TB subjects (p<0.01). Five proteins, CD14, A2GL, NID1, SCTM1, and A1AG1, overlapped between both cohorts. Furthermore, after cross-validation, panels of 5 - 12 proteins were able to predict TB up to two years before diagnosis.

INTERPRETATION

Host proteins can be biomarkers for increasing Mycobacterium tuberculosis infection activity/burden, incipient TB, and predict TB development in PLHIV.

FUNDING

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

Antiretroviral therapy timing impacts latent tuberculosis infection reactivation in a tuberculosis/simian immunodeficiency virus coinfection model

Studies using the nonhuman primate model of Mycobacteriumtuberculosis/simian immunodeficiency virus coinfection have revealed protective CD4⁺ T cell–independent immune responses that suppress latent tuberculosis infection (LTBI) reactivation. In particular, chronic immune activation rather than the mere depletion of CD4⁺ T cells correlates with reactivation due to SIV coinfection. Here, we administered combinatorial antiretroviral therapy (cART) 2 weeks after SIV coinfection to study whether restoration of CD4⁺ T cell immunity occurred more broadly, and whether this prevented reactivation of LTBI compared to cART initiated 4 weeks after SIV. Earlier initiation of cART enhanced survival, led to better control of viral replication, and reduced immune activation in the periphery and lung vasculature, thereby reducing the rate of SIV-induced reactivation. We observed robust CD8⁺ T effector memory responses and significantly reduced macrophage turnover in the lung tissue. However, skewed CD4⁺ T effector memory responses persisted and new TB lesions formed after SIV coinfection. Thus, reactivation of LTBI is governed by very early events of SIV infection. Timing of cART is critical in mitigating chronic immune activation. The potential novelty of these findings mainly relates to the development of a robust animal model of human M. tuberculosis/HIV coinfection that allows the testing of underlying mechanisms.

The impact of blood transcriptomic biomarker targeted tuberculosis preventive therapy in people living with HIV: a mathematical modelling study

BACKGROUND

Tuberculosis (TB) preventive therapy is recommended for all people living with HIV (PLHIV). Despite the elevated risk of TB amongst PLHIV, most of those eligible for preventive therapy would never develop TB. Tests which can identify individuals at greatest risk of disease would allow more efficient targeting of preventive therapy.

METHODS

We used mathematical modelling to estimate the potential impact of using a blood transcriptomic biomarker (RISK11) to target preventive therapy amongst PLHIV. We compared universal treatment to RISK11 targeted treatment and explored the effect of repeat screening of the population with RISK11.

RESULTS

Annual RISK11 screening, with preventive therapy provided to those testing positive, could avert 26% (95% CI 13-34) more cases over 10 years compared to one round of universal treatment. For the cost per case averted to be lower than universal treatment, the maximum cost of the RISK11 test was approximately 10% of the cost of preventive therapy. The benefit of RISK11 screening may be greatest amongst PLHIV on ART (compared to ART naïve individuals) due to the increased specificity of the test in this group.

CONCLUSIONS

Biomarker targeted preventive therapy may be more effective than universal treatment amongst PLHIV in high incidence settings but would require repeat screening.

Annual Tuberculosis Preventive Therapy for Persons With HIV Infection : A Randomized Trial

BACKGROUND

Tuberculosis preventive therapy for persons with HIV infection is effective, but its durability is uncertain.

OBJECTIVE

To compare treatment completion rates of weekly isoniazid-rifapentine for 3 months versus daily isoniazid for 6 months as well as the effectiveness of the 3-month rifapentine-isoniazid regimen given annually for 2 years versus once.

DESIGN

Randomized trial. (ClinicalTrials.gov: NCT02980016).

SETTING

South Africa, Ethiopia, and Mozambique.

PARTICIPANTS

Persons with HIV infection who were receiving antiretroviral therapy, were aged 2 years or older, and did not have active tuberculosis.

INTERVENTION

Participants were randomly assigned to receive weekly rifapentine-isoniazid for 3 months, given either annually for 2 years or once, or daily isoniazid for 6 months. Participants were screened for tuberculosis symptoms at months 0 to 3 and 12 of each study year and at months 12 and 24 using chest radiography and sputum culture.

MEASUREMENTS

Treatment completion was assessed using pill counts. Tuberculosis incidence was measured over 24 months.

RESULTS

Between November 2016 and November 2017, 4027 participants were enrolled; 4014 were included in the analyses (median age, 41 years; 69.5% women; all using antiretroviral therapy). Treatment completion in the first year for the combined rifapentine-isoniazid groups (n = 3610) was 90.4% versus 50.5% for the isoniazid group (n = 404) (risk ratio, 1.78 [95% CI, 1.61 to 1.95]). Tuberculosis incidence among participants receiving the rifapentine-isoniazid regimen twice (n = 1808) or once (n = 1802) was similar (hazard ratio, 0.96 [CI, 0.61 to 1.50]).

LIMITATION

If rifapentine-isoniazid is effective in curing subclinical tuberculosis, then the intensive tuberculosis screening at month 12 may have reduced its effectiveness.

CONCLUSION

Treatment completion was higher with rifapentine-isoniazid for 3 months compared with isoniazid for 6 months. In settings with high tuberculosis transmission, a second round of preventive therapy did not provide additional benefit to persons receiving antiretroviral therapy.

PRIMARY FUNDING SOURCE

The U.S. Agency for International Development through the CHALLENGE TB grant to the KNCV Tuberculosis Foundation.

Low level of tuberculosis preventive therapy incompletion among people living with Human Immunodeficiency Virus in eastern Uganda: A retrospective data review

Introduction

In most developing countries, tuberculosis (TB) is the leading cause of mortality among people living with the Human Immunodeficiency Virus (PLHIV). Uganda implements TB preventive therapy (TPT) using Isoniazid but data are limited about TPT incompletion. We, therefore, assessed the magnitude of TPT incompletion and the associated factors among PLHIV in a large rural referral health facility in rural eastern Uganda.

Methods and materials

We conducted a retrospective data review for PLHIV initiated on TPT between October 2018 and September 2019. The outcome variable was TPT incompletion defined as the failure to finish 6 consecutive months of Isoniazid or failure to finish 9 months of Isoniazid without stopping for more than 2 months at a time. We descriptively summarized numerical data using frequencies and percentages and compared differences in the outcome with independent variables using the Chi-square or fisher’s exact, and the Student’s t-tests. We used a generalized linear model to assess factors independently associated with TPT incompletion, reported using adjusted odds ratio (aOR) and 95% confidence interval (CI).

Results

We enrolled 959 participants with a mean age of 41.1 ± 13.8 years, 561 (58.5%) were females, 663 (69.1%) married, 538 (56.1) travelled 5–10 km from their place of residence to the ART clinic, 293 (30.6%) had disclosed HIV status, 362 (37.7%) had been on ART for 5–9 years, and 923 (96.2%) were on first-line ART regimen. We found 26 (2.7%) participants had incomplete TPT. Non-adherence to ART clinic visits (aOR, 2.81; 95% CI, 1.09–7.73), history of switch in ART regimen (aOR, 9.33; 95% CI, 1.19–52.39), patient representation (aOR, 4.70; 95% CI, 1.35–13.99), and one unit increase in ongoing counselling session (aOR, 0.67; 95% CI, 0.46–0.91) were associated with TPT incompletion.

Conclusion

We found low rates of TPT incompletion among PLHIV in rural eastern Uganda. Non-adherence to ART clinic visits, patient representation, and history of switch in ART regimen is associated with a higher likelihood of TPT incompletion while ongoing counselling is associated with a reduction in TPT incompletion. The health system should address non-adherence to ART clinic visits and patient representation, through ongoing psychosocial support.

A simple protocol for tuberculin skin test reading certification

Although tuberculosis preventive therapy is one of the cornerstones for eliminating the disease, many barriers exist in the cascade of care for latent tuberculosis infection, including the need to certify healthcare professionals for reading tuberculin skin tests (TST). This paper proposes and evaluates a simple protocol for TST reading training. Primary care workers from different backgrounds received a 2-hour theoretical course, followed by a practical course on bleb reading. Blebs were obtained by injecting saline into sausages and then in volunteers. A certified trainer then evaluated the effectiveness of this protocol by analyzing the trainees' ability to read TST induration in clinical routine, blinded to each other's readings. Interobserver agreement was analyzed using the Bland-Altman test. The trainees' reading accuracy was calculated using two cut-off points - 5 and 10mm - and the effect of the number of readings was analyzed using a linear mixed model. Eleven healthcare workers read 53 saline blebs and 88 TST indurations, with high agreement for TST reading (0.07mm average bias). Sensitivity was 100% (94.6; 100.0) at 5mm cut-off and 87.3% (75.5; 94.7) at 10mm cut-off. The regression model found no effect of the number of readings [coefficient: -0.007 (-0.055; 0.040)]. A simple training protocol for reading TST with saline blebs simulations in sausages and volunteers was sufficient to achieve accurate TST induration readings, with no effect observed for the number of readings. Training with saline blebs injected into voluntary individuals is safer and easier than the traditional method.

Tuberculosis preventive therapy for people living with HIV: A systematic review and network meta-analysis

BACKGROUND

Tuberculosis (TB) preventive therapy (TPT) is an essential component of care for people living with HIV (PLHIV). We compared efficacy, safety, completion, and drug-resistant TB risk for currently recommended TPT regimens through a systematic review and network meta-analysis (NMA) of randomized trials.

METHODS AND FINDINGS

We searched MEDLINE, Embase, and the Cochrane Library from inception through June 9, 2020 for randomized controlled trials (RCTs) comparing 2 or more TPT regimens (or placebo/no treatment) in PLHIV. Two independent reviewers evaluated eligibility, extracted data, and assessed the risk of bias. We grouped TPT strategies as follows: placebo/no treatment, 6 to 12 months of isoniazid, 24 to 72 months of isoniazid, and rifamycin-containing regimens. A frequentist NMA (using graph theory) was carried out for the outcomes of development of TB disease, all-cause mortality, and grade 3 or worse hepatotoxicity. For other outcomes, graphical descriptions or traditional pairwise meta-analyses were carried out as appropriate. The potential role of confounding variables for TB disease and all-cause mortality was assessed through stratified analyses. A total of 6,466 unique studies were screened, and 157 full texts were assessed for eligibility. Of these, 20 studies (reporting 16 randomized trials) were included. The median sample size was 616 (interquartile range [IQR], 317 to 1,892). Eight were conducted in Africa, 3 in Europe, 3 in the Americas, and 2 included sites in multiple continents. According to the NMA, 6 to 12 months of isoniazid were no more efficacious in preventing microbiologically confirmed TB than rifamycin-containing regimens (incidence rate ratio [IRR] 1.0, 95% CI 0.8 to 1.4, p = 0.8); however, 6 to 12 months of isoniazid were associated with a higher incidence of all-cause mortality (IRR 1.6, 95% CI 1.2 to 2.0, p = 0.02) and a higher risk of grade 3 or higher hepatotoxicity (risk difference [RD] 8.9, 95% CI 2.8 to 14.9, p = 0.004). Finally, shorter regimens were associated with higher completion rates relative to longer regimens, and we did not find statistically significant differences in the risk of drug-resistant TB between regimens. Study limitations include potential confounding due to differences in posttreatment follow-up time and TB incidence in the study setting on the estimates of incidence of TB or all-cause mortality, as well as an underrepresentation of pregnant women and children.

CONCLUSIONS

Rifamycin-containing regimens appear safer and at least as effective as isoniazid regimens in preventing TB and death and should be considered part of routine care in PLHIV. Knowledge gaps remain as to which specific rifamycin-containing regimen provides the optimal balance of efficacy, completion, and safety.

High conversion of tuberculin skin tests during the first year of antiretroviral treatment among South African adults in primary care

OBJECTIVES

Anergy reduces the sensitivity of the tuberculin skin test (TST) to detect Mycobacterium tuberculosis infection in people living with HIV. Antiretroviral treatment (ART) can reverse TST anergy, but data is scarce.

METHODS

To estimate TST conversion rates and factors associated with TST conversion, TST was placed at ART initiation, and 6 and 12 months thereafter (if TST negative at prior assessment).

RESULTS

Of 328 ART-eligible participants, 70% (231/328) had a valid TST result of whom 78% (180/231) were TST negative. At 6-month follow-up, 22% (24/109, 95% confidence interval [CI] 15%, 31%) of participants on ART, without incident tuberculosis (TB), and with a valid TST result converted to a positive TST. Of these 109 individuals, those with baseline CD4+ cell count >250 cells/μl were more likely to TST convert compared to those with baseline CD4+ cell count ≤250 cells/μl (odds ratio [OR] 3.54, 95% CI 1.29, 11.47). At 12 months post-ART initiation, an additional 12% (9/78, 95% CI 6, 20) of participants on ART, without incident TB and with a valid TST result experienced TST conversion. After 1 year on ART, TST conversion rate was 38 per 100 person-years (95% CI 26, 52), and lower in individuals with baseline CD4+ cell count ≤250 cells/μl (23/100 person-years, 95% CI 11, 41) compared to those with baseline CD4+ cell count >250 cells/μl (50/100 person-years, 95% CI 32, 73).

CONCLUSIONS

TST conversion rate in the first year of ART is high, especially among people with CD4+ cell count >250 cells/μl. A TST-based eligibility strategy at ART initiation may underestimate eligibility for preventive therapy for tuberculosis.

The latent tuberculosis cascade-of-care among people living with HIV: A systematic review and meta-analysis

BACKGROUND

Tuberculosis preventive therapy (TPT) reduces TB-related morbidity and mortality in people living with HIV (PLHIV). Cascade-of-care analyses help identify gaps and barriers in care and develop targeted solutions. A previous latent tuberculosis infection (LTBI) cascade-of-care analysis showed only 18% of persons in at-risk populations complete TPT, but a similar analysis for TPT among PLHIV has not been completed. We conducted a meta-analysis to provide this evidence.

METHODS AND FINDINGS

We first screened potential articles from a LTBI cascade-of-care systematic review published in 2016. From this study, we included cohorts that reported a minimum of 25 PLHIV. To identify new cohorts, we used a similar search strategy restricted to PLHIV. The search was conducted in Medline, Embase, Health Star, and LILACS, from January 2014 to February 2021. Two authors independently screened titles and full text and assessed risk of bias using the Newcastle-Ottawa Scale for cohorts and Cochrane Risk of Bias for cluster randomized trials. We meta-analyzed the proportion of PLHIV completing each step of the LTBI cascade-of-care and estimated the cumulative proportion retained. These results were stratified based on cascades-of-care that used or did not use LTBI testing to determine eligibility for TPT. We also performed a narrative synthesis of enablers and barriers of the cascade-of-care identified at different steps of the cascade. A total of 71 cohorts were included, and 70 were meta-analyzed, comprising 94,011 PLHIV. Among the PLHIV included, 35.3% (33,139/94,011) were from the Americas and 29.2% (27,460/94,011) from Africa. Overall, 49.9% (46,903/94,011) from low- and middle-income countries, median age was 38.0 [interquartile range (IQR) 34.0;43.6], and 65.9% (46,328/70,297) were men, 43.6% (29,629/67,947) were treated with antiretroviral therapy (ART), and the median CD4 count was 390 cell/mm3 (IQR 312;458). Among the cohorts that did not use LTBI tests, the cumulative proportion of PLHIV starting and completing TPT were 40.9% (95% CI: 39.3% to 42.7%) and 33.2% (95% CI: 31.6% to 34.9%). Among cohorts that used LTBI tests, the cumulative proportions of PLHIV starting and completing TPT were 60.4% (95% CI: 58.1% to 62.6%) and 41.9% (95% CI:39.6% to 44.2%), respectively. Completion of TPT was not significantly different in high- compared to low- and middle-income countries. Regardless of LTBI test use, substantial losses in the cascade-of-care occurred before treatment initiation. The integration of HIV and TB care was considered an enabler of the cascade-of-care in multiple cohorts. Key limitations of this systematic review are the observational nature of the included studies, potential selection bias in the population selection, only 14 cohorts reported all steps of the cascade-of-care, and barriers/facilitators were not systematically reported in all cohorts.

CONCLUSIONS

Although substantial losses were seen in multiple stages of the cascade-of-care, the cumulative proportion of PLHIV completing TPT was higher than previously reported among other at-risk populations. The use of LTBI testing in PLHIV in low- and middle-income countries was associated with higher proportion of the cohorts initiating TPT and with similar rates of completion of TPT.

The efficacy of isoniazid prophylaxis in renal transplant recipients in a high tuberculosis burden country

INTRODUCTION

Renal transplant recipients are at high risk of tuberculosis (TB). We started isoniazid (INH) prophylaxis of 1 year duration in all renal transplant recipients from April 2009. Our aim was to assess the incidence of TB on INH prophylaxis and its tolerability.

METHODS

This was a retrospective observational study. The files of renal transplant recipients from April 2009 to December 2011 were reviewed till June 2015. We noted the incidence of TB, INH tolerability, and development of resistance. We compared the incidence of TB with the historical controls who never received the prophylaxis.

RESULTS

A total of 910 patients were reviewed and followed up for 4.8 years. INH prophylaxis was completed by 825 (91%) patients. A total of 46 patients (5%) developed active TB as compared to 15% in the historical controls. The median time of TB diagnosis from transplantation was 2.8 years. In the first-year post transplant, out of total TB cases, 52% occurred in the historical controls whereas 13% occurred in study cohort. Around 67% had TB >2 years after transplant. Overall 1.43% had hepatotoxicity. There was a significant reduction in TB among those who completed prophylaxis to those who did not (p < 0.001). Of 14 cultures, one isolate was INH resistant (7%).

CONCLUSION

INH prophylaxis was well tolerated. The incidence of TB decreased in the first 2 years. However there was a surge in TB cases 1 year after stopping INH therapy. We should consider prolonging the duration of INH prophylaxis in high TB burden countries in renal transplant recipients.

Individual and Composite Adverse Pregnancy Outcomes in a Randomized Trial on Isoniazid Preventative Therapy Among Women Living With Human Immunodeficiency Virus

BACKGROUND

International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) P1078, a randomized noninferiority study designed to compare the safety of starting isoniazid preventive therapy (IPT) in women living with human immunodeficiency virus (HIV) either during pregnancy or after delivery, showed that IPT during pregnancy increased the risk of composite adverse pregnancy outcomes, but not individual outcomes. Many known factors are associated with adverse pregnancy outcomes: these factors' associations and effect modifications with IPT and pregnancy outcomes were examined.

METHODS

Pregnant women living with HIV from 8 countries with tuberculosis incidences >60/100 000 were randomly assigned to initiate 28 weeks of IPT either during pregnancy or at 12 weeks after delivery. Using univariable and multivariable logistic regression and adjusting for factors associated with pregnancy outcomes, composite and individual adverse pregnancy outcome measures were analyzed.

RESULTS

This secondary analysis included 925 mother-infant pairs. All mothers were receiving antiretrovirals. The adjusted odds of fetal demise, preterm delivery (PTD), low birth weight (LBW), or a congenital anomaly (composite outcome 1) were 1.63 times higher among women on immediate compared to deferred IPT (95% confidence interval [CI], 1.15-2.31). The odds of fetal demise, PTD, LBW, or neonatal death within 28 days (composite outcome 2) were 1.62 times higher among women on immediate IPT (95% CI, 1.14-2.30). The odds of early neonatal death within 7 days, fetal demise, PTD, or LBW (composite outcome 3) were 1.74 times higher among women on immediate IPT (95% CI, 1.22-2.49).

CONCLUSIONS

We confirmed higher risks of adverse pregnancy outcomes associated with the initiation of IPT during pregnancy, after adjusting for known risk factors for adverse pregnancy outcomes.

Tuberculosis prevention in children: a prospective community-based study in South Africa

Tuberculosis (TB) preventive therapy reduces TB risk in children. However, the effectiveness of TB preventive therapy in children living in high TB burden settings is unclear.

In a prospective observational community-based cohort study in Cape Town, South Africa, we assessed the effectiveness of routine TB preventive therapy in children ≤15 years of age in a high TB and HIV prevalence setting.

Among 966 children (median (interquartile range) age 5.07 (2.52–8.72) years), 676 (70%) reported exposure to an adult with TB in the past 3 months and 240 out of 326 (74%) eligible children initiated isoniazid preventive therapy under programmatic guidelines. Prevalent (n=73) and incident (n=27) TB were diagnosed among 100 out of 966 (10%) children. Children who initiated isoniazid preventive therapy were 82% less likely to develop incident TB than children who did not (adjusted OR 0.18, 95% CI 0.06–0.52; p=0.0014). Risk of incident TB increased if children were <5 years of age, living with HIV, had a positive Mycobacterium tuberculosis-specific immune response or recent TB exposure. The risk of incident TB was not associated with sex or Mycobacterium bovis bacille Calmette–Guérin vaccination status. Number needed to treat (NNT) was lowest in children living with HIV (NNT=15) and children <5 years of age (NNT=19) compared with children of all ages (NNT=82).

In communities with high TB prevalence, TB preventive therapy substantially reduces the risk of TB among children who are <5 years of age or living with HIV, especially those with recent TB exposure or a positive M. tuberculosis-specific immune response in the absence of disease.

In high TB burden communities, preventive therapy substantially reduces risk of TB among child contacts, especially those who are <5 years of age, living with HIV, recently TB exposed or have a positive M. tuberculosis-specific immune responsehttps://bit.ly/3dKHpUc

Early-phase scale-up of isoniazid preventive therapy for people living with HIV in two districts in Malawi (2017)

Background

Isoniazid preventive therapy (IPT) against tuberculosis (TB) is a life-saving intervention for people living with HIV (PLHIV). In September 2017, Malawi began programmatic scale-up of IPT to eligible PLHIV in five districts with high HIV and TB burden. We measured the frequency and timeliness of early-phase IPT implementation to inform quality-improvement processes.

Methods and findings

We applied a two-stage cluster design with systematic, probability-proportional-to-size sampling of six U.S. Centers for Disease Control and Prevention (CDC)-affiliated antiretroviral therapy (ART) centers operating in the urban areas of Lilongwe and Blantyre, Malawi (November 2017). ART clinic patient volume determined cluster size. Within each cluster, we sequentially sampled approximately 50 PLHIV newly enrolled in ART care. We described a quality-of-care cascade for intensive TB case finding (ICF) and IPT in PLHIV. PLHIV newly enrolled in ART care were eligibility-screened for hepatitis and peripheral neuropathy, as well as for TB disease using a standardized four-symptom screening tool. Among eligible PLHIV, the overall weighted IPT initiation rate was 70% (95% CI: 46%–86%). Weighted IPT initiation among persons aged <15 years (30% [95% CI: 12%–55%]) was significantly lower than among persons aged ≥15 years (72% [95% CI: 47%–89%]; Rao-Scott chi-square P = 0.03). HIV-positive children aged <5 years had a weighted initiation rate of only 13% (95% CI: 1%–79%). For pregnant women, the weighted initiation rate was 67% (95% CI: 32%–90%), similar to non-pregnant women aged ≥15 years (72% [95% CI: 49%–87%]). Lastly, 95% (95% CI: 92%–97%) of eligible PLHIV started ART within one week of HIV diagnosis, and 92% (95% CI: 73%–98%) of patients receiving IPT began on the same day as ART.

Conclusions

Early-phase IPT uptake among adults at ART centers in Malawi was high. Child uptake needed improvement. National programs could adapt this framework to evaluate their ICF-IPT care cascades.

The Profile of the Patients with Double Infection HIV and TB in South West of Romania

Background: Co-infection with human immunodeficiency virus (HIV) / tuberculosis (TB) raises important diagnostic and treatment problems as the lung is one of the target organs for HIV. Studies have shown that an HIV patient is 5-15 times more likely to switch from Koch's bacillus-infected status to active tuberculosis. Material and method: Retrospective study on 207 patients with HIV/TB coinfection in the Oltenia area registered in the Regional Center for Monitoring and Evaluation of HIV/AIDS infection in Craiova to define the profile of patients with double TB-HIV infection in southern Romania for cases registered between 2005-2015. Results: 53.14% of patients were females. Most cases were from rural areas (56.10%) Half of them are born between 1988 and 1990 but only 5% graduated university. 66.18% don’t have a job and are supported by state with a monthly minimum income. 29.4% are smokers. More than 60% of cases had pulmonary TB and other 25% had concomitant pulmonary and extrapulmonary TB. TB and HIV have been diagnosed almost at the same time in 25% of cases. At the time of TB diagnosis 75% of patients had CD4+lymphocytes count <200cel/ml. We also noticed the absence of prophylaxis for TB in patients infected with HIV (PIH) and high incidence of hepatitis B (30.43%). Conclusions: Clinical expression, radiological and bacteriological aspects are often atypical in HIV/TB coinfected patients. The lack of TB prophylaxis and TB endemicity in the studied area may justify the large number of TB cases in HIV-infected patients.

Pulmonary tuberculosis screening in anti-retroviral treated adults living with HIV in Kenya

Background

People living with HIV (PLHIV) who reside in high tuberculosis burden settings remain at risk for tuberculosis disease despite treatment with anti-retroviral therapy and isoniazid preventive therapy (IPT). The performance of the World Health Organization (WHO) symptom screen for tuberculosis in PLHIV receiving anti-retroviral therapy is sub-optimal and alternative screening strategies are needed.

Methods

We enrolled HIV-positive adults into a prospective study in western Kenya. Individuals who were IPT-naïve or had completed IPT > 6 months prior to enrollment were eligible. We evaluated tuberculosis prevalence overall and by IPT status. We assessed the accuracy of the WHO symptom screen, GeneXpert MTB/RIF (Xpert), and candidate biomarkers including C-reactive protein (CRP), hemoglobin, erythrocyte sedimentation rate (ESR), and monocyte-to-lymphocyte ratio for identifying pulmonary tuberculosis. Some participants were evaluated at 6 months post-enrollment for tuberculosis.

Results

The study included 383 PLHIV, of whom > 99% were on antiretrovirals and 88% had received IPT, completed a median of 1.1 years (IQR 0.8–1.55) prior to enrollment. The prevalence of pulmonary tuberculosis at enrollment was 1.3% (n = 5, 95% CI 0.4–3.0%): 4.3% (0.5–14.5%) among IPT-naïve and 0.9% (0.2–2.6%) among IPT-treated participants. The sensitivity of the WHO symptom screen was 0% (0–52%) and specificity 87% (83–90%). Xpert and candidate biomarkers had poor to moderate sensitivity; the most accurate biomarker was CRP ≥ 3.3 mg/L (sensitivity 80% (28–100) and specificity 72% (67–77)). Six months after enrollment, the incidence rate of pulmonary tuberculosis following IPT completion was 0.84 per 100 person-years (95% CI, 0.31–2.23).

Conclusions

In Kenyan PLHIV treated with IPT, tuberculosis prevalence was low at a median of 1.4 years after IPT completion. WHO symptoms screening, Xpert, and candidate biomarkers were insensitive for identifying pulmonary tuberculosis in antiretroviral-treated PLHIV.

HIV-associated tuberculosis

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

Novel health system strategies for tuberculin skin testing at primary care clinics: Performance assessment and health economic evaluation

Background

Tuberculin skin test (TST) for guiding initiation of tuberculosis preventive therapy poses major challenges in high tuberculosis burden settings.

Methods

At a primary care clinic in Johannesburg, South Africa, 278 HIV-positive adults self-read their TST by reporting if they felt a bump (any induration) at the TST placement site. TST reading (in mm) was fast-tracked to reduce patient wait time and task-shifted to delegate tasks to lower cadre healthcare workers, and result was compared to TST reading by high cadre research staff. TST reading and placement cost to the health system and patients were estimated. Simulations of health system costs were performed for 5 countries (USA, Germany, Brazil, India, Russia) to evaluate generalizability.

Results

Almost all participants (269 of 278, 97%) correctly self-identified the presence or absence of any induration [sensitivity 89% (95% CI 80,95) and specificity 99.5% (95% CI 97,100)]. For detection of a positive TST (induration ≥ 5mm), sensitivity was 90% (95% CI 81,96) and specificity 99% (95% CI 97,100). TST reading agreement between low and high cadre staff was high (kappa 0.97, 95% CI 0.94, 1.00). Total TST cost was 2066 I$ (95% UI 594, 5243) per 100 patients, 87% (95% UI 53, 95) of which were patient costs. Combining fast-track and task-shifting, reduced total costs to 1736 I$ (95% UI 497, 4300) per 100 patients, with 31% (95% UI 15, 42) saving in health system costs. Combining fast-tracking, task-shifting and self-reading, lowered the TST health system costs from 16% (95% UI 8, 26) in Russia to 40% (95% UI 18, 54) in the USA.

Conclusion

A TST strategy where only patients with any self-read induration are asked to return for fast-tracked TST reading by lower cadre healthcare workers is a promising strategy that could be effective and cost-saving, but real-life cost-effectiveness should be further examined.

A science impact framework to measure impact beyond journal metrics

Measuring the impact of public health science or research is important especially when it comes to health outcomes. Achieving the desired health outcomes take time and may be influenced by several contributors, making attribution of credit to any one entity or effort problematic. Here we offer a science impact framework (SIF) for tracing and linking public health science to events and/or actions with recognized impact beyond journal metrics. The SIF was modeled on the Institute of Medicine's (IOM) Degrees of Impact Thermometer, but differs in that SIF is not incremental, not chronological, and has expanded scope. The SIF recognizes five domains of influence: disseminating science, creating awareness, catalyzing action, effecting change and shaping the future (scope differs from IOM). For public health, the goal is to achieve one or more specific health outcomes. What is unique about this framework is that the focus is not just on the projected impact or outcome but rather the effects that are occurring in real time with the recognition that the measurement field is complex, and it takes time for the ultimate outcome to occur. The SIF is flexible and can be tailored to measure the impact of any scientific effort: from complex initiatives to individual publications. The SIF may be used to measure impact prospectively of an ongoing or new body of work (e.g., research, guidelines and recommendations, or technology) and retrospectively of completed and disseminated work, through linking of events using indicators that are known and have been used for measuring impact. Additionally, linking events offers an approach to both tell our story and also acknowledge other players in the chain of events. The value added by science can easily be relayed to the scientific community, policy makers and the public.

Evaluation of 6-Month Versus Continuous Isoniazid Preventive Therapy for Mycobacterium tuberculosis in Adults Living With HIV/AIDS in Malawi

BACKGROUND

To assist the Malawi Ministry of Health to evaluate 2 competing strategies for scale-up of isoniazid preventive therapy (IPT) among HIV-positive adults receiving antiretroviral therapy.

SETTING

Malawi.

METHODS

We used a multidistrict, compartmental model of the Malawi tuberculosis (TB)/HIV epidemic to compare the anticipated health impacts of 6-month versus continuous IPT programs over a 12-year horizon while respecting a US$10.8 million constraint on drug costs in the first 3 years.

RESULTS

The 6-month IPT program could be implemented nationwide, whereas the continuous IPT alternative could be introduced in 14 (of the 27) districts. By the end of year 12, the continuous IPT strategy was predicted to avert more TB cases than the 6-month alternative, although not statistically significant (2368 additional cases averted; 95% projection interval [PI], -1459 to 5023). The 6-month strategy required fewer person-years of IPT to avert a case of TB or death than the continuous strategy. For both programs, the mean reductions in TB incidence among people living with HIV by year 12 were expected to be <10%, and the cumulative numbers of IPT-related hepatotoxicity to exceed the number of all-cause deaths averted in the first 3 years.

CONCLUSIONS

With the given budgetary constraint, the nationwide implementation of 6-month IPT would be more efficient and yield comparable health benefits than implementing a continuous IPT program in fewer districts. The anticipated health effects associated with both IPT strategies suggested that a combination of different TB intervention strategies would likely be required to yield a greater impact on TB control in settings such as Malawi, where antiretroviral therapycoverage is relatively high.

Protocol for a Case-Control Study to Investigate the Association of Pellagra With Isoniazid Exposure During Tuberculosis Preventive Treatment Scale-Up in Malawi

Background: Pellagra is caused by niacin (vitamin B3) deficiency and manifested by a distinctive dermatitis. Isoniazid is critical for treating tuberculosis globally and is a component of most regimens to prevent tuberculosis. Isoniazid may contribute to pellagra by disrupting intracellular niacin synthesis. In 2017, Malawian clinicians recognized a high incidence of pellagra-like rashes after scale-up of isoniazid preventive treatment (IPT) to people living with HIV (PLHIV). This increase in pellagra incidence among PLHIV coincided with a seasonal period of sustained food insecurity in the region, which obscured epidemiological interpretations. Although isoniazid has been implicated as a secondary cause of pellagra for decades, no hypothesis-driven epidemiological study has assessed this relationship in a population exposed to isoniazid. We developed this case-control protocol to assess the association between large-scale isoniazid distribution and pellagra in Malawi. Methods: We measure the relative odds of having pellagra among isoniazid-exposed people compared to those without exposure while controlling for other pellagra risk factors. Secondary aims include measuring time from isoniazid initiation to onset of dermatitis, comparing niacin metabolites 1-methylnicotinamide (1-MN), and l-methyl-2-pyridone-5-carboxamide (2-PYR) in urine as a proxy for total body niacin status among subpopulations, and describing clinical outcomes after 30-days multi-B vitamin (containing 300 mg nicotinamide daily) therapy and isoniazid cessation (if exposed). We aim to enroll 197 participants with pellagra and 788 age- and sex-matched controls (1:4 ratio) presenting at three dermatology clinics. Four randomly selected community clinics within 3-25 km of designated dermatology clinics will refer persons with pellagra-like symptoms to one of the study enrollment sites for diagnosis. Trained study dermatologists will conduct a detailed exposure questionnaire and perform anthropometric measurements. A subset of enrollees will provide a casual urine specimen for niacin metabolites quantification and/or point-of-care isoniazid detection to confirm whether participants recently ingested isoniazid. We will use conditional logistic regression, matching age and sex, to estimate odds ratios for the primary study aim. Discussion: The results of this study will inform the programmatic scale-up of isoniazid-containing regimens to prevent tuberculosis.

Safety and Effectiveness of Isoniazid Preventive Therapy in Pregnant Women Living with Human Immunodeficiency Virus on Antiretroviral Therapy: An Observational Study Using Linked Population Data

BACKGROUND

Isoniazid preventive therapy (IPT) is widely used to protect against tuberculosis (TB) in people living with human immunodeficiency virus (HIV). Data on the safety and efficacy of IPT in pregnant women living with HIV (PWLHIV) are mixed. We used an individual-level, population-wide health database to examine associations between antenatal IPT exposure and adverse pregnancy outcomes, maternal TB, all-cause mortality, and liver injury during pregnancy through 12 months postpartum.

METHODS

We used linked routine electronic health data generated in the public sector of the Western Cape, South Africa, to define a cohort of PWLHIV on antiretroviral therapy. Pregnancy outcomes were assessed using logistic regression; for maternal outcomes we applied a proportional hazards model with time-updated IPT exposure.

RESULTS

Of 43 971 PWLHIV, 16.6% received IPT. Women who received IPT were less likely to experience poor pregnancy outcomes (adjusted odds ratio [aOR], 0.83 [95% confidence interval {CI}, .78-.87]); this association strengthened with IPT started after the first trimester compared with none (aOR, 0.71 [95% CI, .65-.79]) or with first-trimester exposure (aOR, 0.64 [95% CI, .55-.75]). IPT reduced the risk of TB by approximately 30% (aHR, 0.71 [95% CI, .63-.81]; absolute risk difference, 1518/100 000 women). The effect was modified by CD4 cell count with protection conferred if CD4 count was ≤350 cells/μL (aHR, 0.51 [95% CI, .41-.63]) vs 0.93 [95% CI, .76-1.13] for CD4 count >350 cells/µL).

CONCLUSIONS

This analysis of programmatic data is reassuring regarding the safety of antenatal IPT, with the greatest benefits against TB disease observed in women with CD4 count ≤350 cells/μL.

Tuberculosis-HIV Co-Infection: Progress and Challenges After Two Decades of Global Antiretroviral Treatment Roll-Out

Despite wide antiretroviral scale-up during the past two decades resulting in declining new infections and mortality globally, HIV-associated tuberculosis remains as a major public health concern. Tuberculosis is the leading HIV-associated opportunistic infection and the main cause of death globally and, particularly, in resource-limited settings. Several challenges exist regarding diagnosis, global implementation of latent tuberculosis treatment, management of active tuberculosis, delivery of optimal patient-centered TB and HIV prevention and care in high burden countries. In this article we review the advances on pathogenesis, diagnosis, and treatment after nearly two decades of global roll-out of antiretroviral therapy and discuss the current challenges for the global control of tuberculosis-HIV co-infection.

The shift in tuberculosis timing among people living with HIV in the course of antiretroviral therapy scale-up in Malawi

Introduction

Although the use of antiretroviral therapy (ART) reduces HIV‐associated tuberculosis (TB), patients living with HIV receiving ART remain at a higher risk of developing TB compared to those without HIV. We investigated the incidence of TB and the proportion of HIV‐associated TB cases among patients living with HIV who are receiving ART.

Methods

The study used TB registration and ART programme data collected between 2008 and 2017 from an integrated, public clinic in urban Lilongwe, Malawi. ART initiation was based on either WHO clinical staging or CD4 cell count. The CD4 thresholds for ART initiation eligibility was initially 250 cells/μL then changed to 350 cells/μL in 2011, 500 cells/μL in 2014 and to universal treatment upon diagnosis from 2016. Using TB registration data, we calculated the proportion of TB/HIV patients who were already on ART when they registered for TB treatment by year of TB registration. ART registration data were used to examine TB incidence by calendar year of ART follow‐up and by time on ART.

Results

The overall proportion of TB/patients living with HIV who started TB treatment while on ART increased from 21% in 2008 to 81% in 2017 but numbers remained relatively constant at 500 TB cases annually. The overall incidence rate of TB among patients on ART was 1.35/100 person‐years (95% CI 1.28 to 1.42). The incidence of TB by time on ART decreased from 6.4/100 person‐years in the first three months of ART to 0.4/100 person‐years after eight years on ART. TB incidence was highest in the first month on ART. The annual rate of TB among patients on ART rapidly decreased each calendar year and stabilized at 1% after 2013. Although the risk of developing TB decreased with year of ART initiation in univariable analysis, there was no significant association after adjusting for sex, age and reason for ART eligibility.

Conclusions

The decline in TB incidence over calendar years suggests protective effects of early ART initiation. The high TB incidence within the first month of ART highlights the need for more sensitive tools such as X‐ray and GeneXpert to identify patients living with HIV who have clinical and subclinical TB disease at ART initiation.

Treatment of Latent Tuberculosis Infection-An Update

Treatment of latent tuberculosis infection (LTBI) is an important component of TB control and elimination. LTBI treatment regimens include once-weekly isoniazid plus rifapentine for 3 months, daily rifampin for 4 months, daily isoniazid plus rifampin for 3-4 months, and daily isoniazid for 6-9 months. Isoniazid monotherapy is efficacious in preventing TB disease, but the rifampin- and rifapentine-containing regimens are shorter and have similar efficacy, adequate safety, and higher treatment completion rates. Novel vaccine strategies, host immunity-directed therapies and ultrashort antimicrobial regimens for TB prevention, such as daily isoniazid plus rifapentine for 1 month, are under evaluation.

Incidence and predictors of tuberculosis occurrence among adults on antiretroviral therapy at Debre Markos referral hospital, Northwest Ethiopia: retrospective follow-up study

BACKGROUND

In resource limited settings, Tuberculosis (TB) is a major cause of morbidity and mortality among patients on antiretroviral treatment. Ethiopia is one of the 30 high TB burden countries. TB causes burden in healthcare system and challenge the effectiveness of HIV care. This study was to assess incidence and predictors of Tuberculosis among adults on antiretroviral therapy at Debre Markos Referral Hospital, Northwest Ethiopia, 2019.

METHODS

Institution based retrospective follow up study was conducted among adults on ART newly enrolled from 2014 to 2018 at Debre Markos Referral Hospital. Simple random sampling technique was used to select patients chart. Data was entered to EPI- INFO version 7.2.2.6 and analyzed using Stata 14.0. Tuberculosis incidence rate was computed and described using frequency tables. Both bivariable and multivariable Cox proportional hazard models was fitted to identify predictors of TB.

RESULTS

Out of the 536 patients chart reviewed, 494 patient records were included in the analysis. A total of 62 patients developed new TB cases during the follow up period of 1000.22 Person Years (PY); which gives an overall incidence rate of 6.19 cases per 100 PY (95% CI: 4.83-7.95). The highest rate was seen within the first year of follow up. After adjustment base line Hemoglobin < 10 g/dl (AHR = 5.25; 95% CI: 2.52-10.95), ambulatory/bedridden patients at enrolment (AHR = 2.31; 95% CI: 1.13-4.73), having fair or poor ART adherence (AHR = 3.22; 95% CI: 1.64-6.31) were associated with increased risk of tuberculosis whereas taking Isoniazid Preventive Therapy (IPT) (AHR = 0.33; 95% CI: 0.12-0.85) were protective factors of TB occurrence.

CONCLUSION

TB incidence was high among adults on ART especially in the first year of enrollment to ART. Low hemoglobin level, ambulatory or bedridden functional status, non-adherence to ART and IPT usage status were found to be independent predictors. Hence, continuous follow up for ART adherence and provision of IPT has a great importance to reduce the risk of TB.

Guidelines for the Treatment of Latent Tuberculosis Infection: Recommendations from the National Tuberculosis Controllers Association and CDC, 2020

Comprehensive guidelines for treatment of latent tuberculosis infection (LTBI) among persons living in the United States were last published in 2000 (American Thoracic Society. CDC targeted tuberculin testing and treatment of latent tuberculosis infection. Am J Respir Crit Care Med 2000;161:S221–47). Since then, several new regimens have been evaluated in clinical trials. To update previous guidelines, the National Tuberculosis Controllers Association (NTCA) and CDC convened a committee to conduct a systematic literature review and make new recommendations for the most effective and least toxic regimens for treatment of LTBI among persons who live in the United States.

The systematic literature review included clinical trials of regimens to treat LTBI. Quality of evidence (high, moderate, low, or very low) from clinical trial comparisons was appraised using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. In addition, a network meta-analysis evaluated regimens that had not been compared directly in clinical trials. The effectiveness outcome was tuberculosis disease; the toxicity outcome was hepatotoxicity. Strong GRADE recommendations required at least moderate evidence of effectiveness and that the desirable consequences outweighed the undesirable consequences in the majority of patients. Conditional GRADE recommendations were made when determination of whether desirable consequences outweighed undesirable consequences was uncertain (e.g., with low-quality evidence).

These updated 2020 LTBI treatment guidelines include the NTCA- and CDC-recommended treatment regimens that comprise three preferred rifamycin-based regimens and two alternative monotherapy regimens with daily isoniazid. All recommended treatment regimens are intended for persons infected with Mycobacterium tuberculosis that is presumed to be susceptible to isoniazid or rifampin. These updated guidelines do not apply when evidence is available that the infecting M. tuberculosis strain is resistant to both isoniazid and rifampin; recommendations for treating contacts exposed to multidrug-resistant tuberculosis were published in 2019 (Nahid P, Mase SR Migliori GB, et al. Treatment of drug-resistant tuberculosis. An official ATS/CDC/ERS/IDSA clinical practice guideline. Am J Respir Crit Care Med 2019;200:e93–e142). The three rifamycin-based preferred regimens are 3 months of once-weekly isoniazid plus rifapentine, 4 months of daily rifampin, or 3 months of daily isoniazid plus rifampin. Prescribing providers or pharmacists who are unfamiliar with rifampin and rifapentine might confuse the two drugs. They are not interchangeable, and caution should be taken to ensure that patients receive the correct medication for the intended regimen. Preference for these rifamycin-based regimens was made on the basis of effectiveness, safety, and high treatment completion rates. The two alternative treatment regimens are daily isoniazid for 6 or 9 months; isoniazid monotherapy is efficacious but has higher toxicity risk and lower treatment completion rates than shorter rifamycin-based regimens.

In summary, short-course (3- to 4-month) rifamycin-based treatment regimens are preferred over longer-course (6–9 month) isoniazid monotherapy for treatment of LTBI. These updated guidelines can be used by clinicians, public health officials, policymakers, health care organizations, and other state and local stakeholders who might need to adapt them to fit individual clinical circumstances.

The Mtb-HIV syndemic interaction: why treating M. tuberculosis infection may be crucial for HIV-1 eradication

Accelerated tuberculosis and AIDS progression seen in HIV-1 and Mycobacterium tuberculosis (Mtb)-coinfected individuals indicates the important interaction between these syndemic pathogens. The immunological interaction between HIV-1 and Mtb has been largely defined by how the virus exacerbates tuberculosis disease pathogenesis. Understanding of the mechanisms by which pre-existing or subsequent Mtb infection may favor the replication, persistence and progression of HIV, is less characterized. We present a rationale for the critical consideration of ‘latent’ Mtb infection in HIV-1 prevention and cure strategies. In support of this position, we review evidence of the effect of Mtb infection on HIV-1 acquisition, replication and persistence. We propose that ‘latent’ Mtb infection may have considerable impact on HIV-1 pathogenesis and the continuing HIV-1 epidemic in sub-Saharan Africa.

Infant TB Infection Prevention Study (iTIPS): a randomised trial protocol evaluating isoniazid to prevent M. tuberculosis infection in HIV-exposed uninfected children

INTRODUCTION

HIV-exposed uninfected (HEU) infants in tuberculosis (TB) endemic settings are at high risk of Mycobacterium tuberculosis (Mtb) infection and TB disease, even in the absence of known Mtb exposure. Because infancy is a time of rapid progression from primary infection to active TB disease, it is important to define when and how TB preventive interventions exert their effect in order to develop effective prevention strategies in this high-risk population.

METHODS AND ANALYSIS

We designed a non-blinded randomised controlled trial to determine efficacy of isoniazid (INH) to prevent primary Mtb infection among HEU children. Target sample size is 300 (150 infants in each arm). Children are enrolled at 6 weeks of age from maternal and child health clinics in Kenya and are randomised to receive 12 months of daily INH ~10 mg/kg plus pyridoxine or no INH. The primary endpoint is Mtb infection, assessed by interferon-gamma release assay QuantiFERON-TB Gold Plus (QFT-Plus) or tuberculin skin test after 12 months post-enrolment. Secondary outcomes include severe adverse events, expanded Mtb infection definition using additional QFT-Plus supernatant markers and determining correlates of Mtb infection. Exploratory analyses include a combined outcome of TB infection, disease and mortality, and sensitivity analyses excluding infants with baseline TB-specific responses on flow cytometry.

ETHICS AND DISSEMINATION

An external and independent Data and Safety Monitoring Board monitors adverse events. Results will be disseminated through peer-reviewed journals, presentations at local and international conferences to national and global policy-makers, the local community and participants.

TRIAL REGISTRATION NUMBER

NCT02613169; Pre-results.