National policies on the management of latent tuberculosis infection: review of 98 countries

A Review of Workplace Tuberculosis Policies in Selected Low- and Middle-Income Countries in Asia-Pacific

Background and Objective

The World Health Organization (WHO) reported that most of the tuberculosis (TB) cases are aged between 15 to 54 years old, the working population. This study described workplace policies on TB in selected low- and middle-income countries (LMIC) in Asia-Pacific.

Methods

Among the LMICs, countries wherein TB is a public health concern were included. Six policies written in English were included in this study and were reviewed based on the components of the TB workplace programs that were extracted from the WHO Guidelines for Workplace TB Control Activities.

Results

The Philippine policy had the most number of components while those of Cambodia and Papua New Guinea had the least. Only the component on implementing environmental controls was common among the policies. Components on respecting patient rights and confidentiality, tailoring of workload to TB patient's state of health, registration of all patients with TB diagnosis, reporting of cases to central NTP office, recording of standard treatment outcome, and inclusion of multidrug-resistant TB (MDR-TB) provisions were missing for the majority of the policy documents.

Conclusion

The workplace TB program policies included in this study can be reviewed and updated accordingly, with the coverage expanding to all workplaces. The policies can also integrate measures on COVID-19 as the pandemic has slowed the progress in TB control. With the similarities in the preventive measures against TB and COVID-19, this can be an avenue to develop integrated policies especially for workplaces.

Tuberculosis among children visiting friends & relatives

BACKGROUND

Most paediatric tuberculosis (TB) cases in low-TB-incidence countries involve children born to migrant families. This may be partially explained by trips to their countries of origin for visiting friends and relatives (VFR). We aimed to estimate the risk of latent TB infection (LTBI) and TB in children VFR.

METHODS

We conducted a prospective multicentric observational study in Catalonia (Spain) from June 2017 to December 2019. We enrolled children aged < 15 years with a negative tuberculin skin test (TST) at baseline and at least one parent from a high-TB-incidence country, and who had travelled to their parent's birth country for ≥21 days. TST and QuantiFERON-TB Gold Plus (QFT-Plus) were performed within 8-12 weeks post-return. LTBI was defined as a TST ≥5 mm and/or a positive QFT-Plus.

RESULTS

Five hundred children completed the study, equivalent to 78.2 person-years of follow-up (PYFU). Thirteen children (2.6%) were diagnosed with LTBI (16.6/per100 PYFU, 95%CI = 8.8-28.5), including two cases (0.4%) of TB (2.5/per100 PYFU, 95%CI = 0.3-9.3). LTBI incidence rates remained high after excluding BCG-vaccinated children (9.7/per100 PYFU, 95%CI = 3.9-20.0). Household tobacco smoke exposure was associated with LTBI (aOR = 3.9, 95%CI = 1.1-13.3).

CONCLUSIONS

The risk of LTBI in children VFR in high-TB-incidence countries may equal, or perhaps even exceed, the infection risk of the native population. The primary associated risk factor was the presence of smokers in the household. Furthermore, the incidence rate of active TB largely surpassed that of the countries visited. Children VFR in high-TB-incidence countries should be targeted for diagnostic and preventive interventions.

Risk of tuberculosis among pulmonary tuberculosis contacts: the importance of time of exposure to index cases

INTRODUCTION

The intensity of exposure to index cases of tuberculosis [TB] may increase the risk of TB in their contacts. The aim was to determine TB risk factors among contacts of TB index cases.

METHODS

A cohort study was carried out in the contacts of pulmonary TB cases registered by the epidemiological surveillance network from 01/01/2019 to 06/30/2021. The factors associated with the risk of TB in contacts were determined using the adjusted odds ratio [aOR] and its 95% confidence interval [CI].

RESULTS

From 847 TB cases, 7087 contacts were identified. The prevalence of TB was 2.0% [145/7087] and was higher in < 5 years compared to those ≥ 65 years [4.4% versus 1.2%; p < 0.001], in those exposed ≥ 6 h daily [4%], and < 6 h daily [1.6%] with respect to weekly exposure of < 6 h [0.7%; p < 0.001]. Those contacts exposed ≥ 6 h daily [aOR= 6.9; 95%CI:2.1-22.1], < 5 years [aOR= 8.3; 95%CI:1.8-37.8] and immigrants [aOR= 1.7; 95%CI:1.1-2.7] had a higher risk of TB.

CONCLUSIONS

The risk of TB increases with the time of exposure to the index case and this risk is also higher in < 5 years and immigrants. Contact tracing has a high yield for detecting new cases of TB.

Lack of reactivation of tuberculosis in patients with psoriasis treated with secukinumab in a real-world setting of latent tuberculosis infection

BACKGROUND

Some biologics for psoriasis, especially anti-tumor necrosis factor (TNF)-α therapies, may re-activate latent tuberculosis (TBC) infection with consequent morbidity and mortality. However, there is a low reported incidence of conversion to positive TBC status among patients with psoriasis treated with second-generation biologic therapies, particularly anti-interleukin (IL)-17 therapies such as secukinumab.

OBJECTIVES

To evaluate the safety profile of secukinumab in psoriasis patients with latent TBC infection.

METHODS

Real-life data were collected by retrospective chart review on patients with moderate-to-severe psoriasis who showed positivity for TBC screening at baseline and underwent secukinumab treatment for psoriasis at six Italian centers. Patients received secukinumab 300 mg at week 0/1/2/3/4, then every 4 weeks.

RESULTS

Fifty-nine patients were enrolled; 30.5% also had psoriatic arthritis and other comorbidities were common. At baseline, the mean psoriasis duration was 14.5 years. Ten (17%) patients did not undergo prophylaxis before starting secukinumab. Conversely, isoniazid ± rifampicin or rifampicin alone prophylaxis was administered in 49/59 (83.1%) patients. After a mean treatment duration of 84 weeks, there were no cases of TBC reactivation and no unexpected safety signals.

CONCLUSIONS

Secukinumab use over an extended period was safe in psoriasis patients with latent TBC, even in patients who did not receive chemoprophylaxis.

Framing the Detection of Incipient Tuberculosis Infection: a qualitative study of political prioritization

Objective

Incipient Tuberculosis (ITB) refers to Mycobacterium tuberculosis infection that is likely to progress to active disease in the absence of treatment, but without clinical signs, symptoms, radiographic or microbiological evidence of disease. Biomarker‐based tests to diagnose incipient TB hold promise for better prediction and, through TB preventive therapy, prevention of disease. This study explored current and future framing and prioritisation of ITB.

Methods

Twenty‐two interviews across eight countries were conducted. A modified Shiffman & Smith Framework, containing four categories—Ideas, Issue Characteristics, Actor Power, and Political Contexts—was used to analyse the current landscape and potential for prioritisation of diagnosis and treatment of ITB.

Results

Latent TB policy implementation has been slow due to technical, logistical and financial challenges, and because it has been framed in a manner non‐conducive to gaining political priority. Framing ITB testing as ‘early detection’ rather than ‘prediction’, and its management as ‘treatment’ rather than ‘preventive therapy’, may help raise its importance in policies, and its acceptance among actors.

Conclusion

Consensus surrounding the framing of ITB will be crucial for the successful adoption of ITB diagnostics and treatment. When designing ITB tools and policies, it will be important to address challenges that pertain to latent TB policies.

Investigation of Contacts for Latent Mycobacterium Tuberculosis Infection: Application Software Development

Introduction:

Tuberculosis is a pathology that continues to be worthy of special attention from health professionals and society due to its high prevalence, proving to be a crucial public health problem.

Objectives:

To describe the development of an application for family health strategy professionals’ investigation of tuberculosis contacts for Latent Mycobacterium tuberculosis Infection.

Methods:

This study is applied research on an application software developed according to three of the five phases described by Falkembach for developing digital educational materials, which include analysis and planning, modeling, and implementation.

Results:

The application is dynamic; that is, it guides health professionals through sequenced screens according to professionals’ self-informed answers. This functionality helps them deciding whether to proceed to the treatment of the patient with Latent Mycobacterium tuberculosis Infection or returning to the initial stage of a tuberculosis contact.

The screens of the application follow the flowchart presented in the Ministry of Health’s Manual of recommendations for tuberculosis control in Brazil of 2018.

Conclusion:

The application developed to guide Family Health Strategy professionals regarding Latent Infection by Mycobacterium Tuberculosis can prevent human errors and increase the care quality when assessing tuberculosis contacts.

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).

Pathogenetic role of tumor necrosis factor (TNF-α) for the development of peritoneal tuberculosis in an experiment

Currently tuberculosis is considered as a group of diseases united by one etiological factor. The pathogenesis of certain localizations of tuberculous inflammation, in particular peritoneum tuberculosis, hasn’t been sufficiently studied. The role of cytokine mechanisms in the development of the disease and the elaboration of non-sterile immunity requires further experimental studies, in particular the creation of a reproducible model on laboratory animals.

The aim: to study the effect of TNF-α on the development of tuberculosis of the serous coat of the abdominal cavity, as well as to evaluate the possibility of modeling tuberculous peritonitis in laboratory animals using infliximab.

Materials and methods. The studies were conducted on 18 male rabbits, which were simulated peritoneal tuberculosis by intra-abdominal administration of a suspension of Mycobacterium tuberculosis. 10 rabbits of the experimental group were intravenously injected with an infliximab solution and an iron (III) hydroxide sucrose complex intraperitoneally a day before infection.

Results. In the control group of animals, tuberculosis either didn’t develop, or in a third of cases it affected only the pulmonary parenchyma, while proliferative processes prevailed. On the contrary, in animals with inactivated TNF-α, in 100 % of observations, tuberculous peritonitis was detected with associated lung damage and the predominance of alterative caseous processes.

Conclusion. The created model of tuberculous peritonitis shows the leading role of TNF-α in the activation of macrophages, as well as in attracting cells to the site of infection. This is the primary signal necessary for the formation and stability of granulomas since the neutralization of this cytokine leads to a loss of control over the infection and the destruction of the granuloma with the development of destructive tuberculosis in the serous coat of the abdominal cavity. 

Prevalence of latent tuberculosis and associated factors in patients with chronic kidney disease on hemodialysis

Objective:

to identify the prevalence of latent tuberculosis in patients with chronic kidney disease on hemodialysis and associated factors.

Method:

a cross-sectional study conducted with 176 patients with chronic kidney disease on hemodialysis. The tuberculin test was performed with the standardized antigen, distributed by the Brazilian Ministry of Health, and the reading occurred after 72 to 96 hours of the application. An association test (Chi-square, Fisher’s exact), prevalence ratio, and multivariate regression tests were performed.

Results:

the prevalence of latent tuberculosis diagnosed through Tuberculosis Skin Test was 8.5% (15/176). The “has/has had diabetes” (aOR: 0.117; 95%CI: 0.015-0.92) and “having regular garbage collection (aOR: 0.076; 95%CI: 0.008-0.702) factors were associated with a lower probability of having a Positive skin test.

Conclusion:

the low prevalence of latent tuberculosis identified and the factors associated with it reinforce the need for screening for latent tuberculosis infection for diabetics combined with an analysis of previous risk factors and comorbidities.

Treatment seeking delay and associated factors among tuberculosis patients attending health facility in Ethiopia from 2000 to 2020: A systematic review and meta analysis

Background

Treatment seeking delay is defined as the time interval between the onset of the major symptoms of tuberculosis (TB) and the first visit to the formal health care facility. The patient was said to be delayed if the patient visited the health-facility after 3 weeks onset of major symptoms. However, in low-income countries like Ethiopia, the delay in treatment-seeking among tuberculosis patients contributes to a widespread transmission and high prevalence of tuberculosis.

Methods

Studies were retrieved from PubMed, Cochrane Database, Cinahl, Scopus, Mednar, and Google Scholar by employing a combination of search terms with Boolean operators. Heterogeneity across studies was assessed using the Cochrane Q test. A funnel plot was used for visual assessment of publication bias. Subgroup analyses were performed to explore the possible causes of heterogeneity. Egger’s weighted regression test at a p-value < 0.05 was used to assess the presence of publication bias. Sensitivity analysis was performed to judge whether the pooled effect size was influenced by individual study. STATA software version 14 was used for all statistical analyses.

Result

A total of 12 studies with 5122 total sample size were included. The national pooled prevalence of treatment seeking delay was 44.29% (95% CI: 39.805, 48.771). The visual inspection of the funnel plot showed the asymmetrical distribution, and the Egger test showed insignificant (P = 0.348). Patients who did not seek formal health care providers on a first contact had about 7 times more likely to delay than patients who sought formal health care provider on a first contact (OR: 7.192 ((95% CI 5.587–9.257), P = 0.001, I²: 85%). The others independent predictors of delay were rural residence (OR: 3.459 ((95% CI 1.469–8.148), P ≤ 0.001), extra pulmonary TB (OR: 2.520 ((95% CI 1.761–3.605), 0.180), lower educational level (OR 11.720 ((95% CI 1.006–2.938), P <0.001), and distance more than 10km from health facility (OR: 1.631 ((95% CI (10.858–3.101), P = 0.001).

Conclusion

In this review, we identified a substantial treatment seeking delay among TB patients in Ethiopia. And, the independent predictors of delay were treatment sought before formal health care provider, residence of the patient, type of TB, educational level, and distance from a health facility. Thus, we recommend health extension workers, health professionals and other stakeholders to focus on patient education, and to continuously mobilize the whole communities on early treatment seeking with a special emphasis given to where treatment sought before formal health care provider, rural resident, extra pulmonary TB, and a patient living farther than 10km distance from health facility.

Active case finding of pulmonary TB in a European refugee camp: lessons learnt from Oinofyta hosting site in Greece

OBJECTIVES

To report on an active case finding (ACF) intervention that took place in the migrant camp of Oinofyta, Greece, upon suspicion of active TB transmission.

METHODS

Upon diagnosis of 3 TB cases among camp residents, an ACF intervention among contacts was implemented. All camp residents were offered two-step screening, that is tuberculin skin testing (TST) followed by chest X-ray in case of positive TST (defined as ≥5 mm).

RESULTS

336 of 379 (89%) camp residents underwent TST testing, of whom 110 (33%) exhibited a positive skin reaction. The rate of positive TST results was particularly high in the elderly and significantly higher in adults than in children. Differences by sex or nationality were not observed. Of the 110 cases with positive TST, only 75 underwent chest X-ray, resulting in the detection of one pulmonary TB case in an adult woman.

CONCLUSIONS

In the given intervention context, two-step ACF proved to be operationally cumbersome, with many residents lost to follow-up and a high Number Needed to Screen. Simpler ACF designs should be pilot-tested in similar settings in the future, and blanket screening of all camp residents should be reconsidered. Conclusions drawn by these exercises should pave the way for adopting a comprehensive, context-specific and evidence-based national strategy on TB in migrants.

Validation of Differentially Expressed Immune Biomarkers in Latent and Active Tuberculosis by Real-Time PCR

Tuberculosis (TB) remains a major global threat and diagnosis of active TB ((ATB) both extra-pulmonary (EPTB), pulmonary (PTB)) and latent TB (LTBI) infection remains challenging, particularly in high-burden countries which still rely heavily on conventional methods. Although molecular diagnostic methods are available, e.g., Cepheid GeneXpert, they are not universally available in all high TB burden countries. There is intense focus on immune biomarkers for use in TB diagnosis, which could provide alternative low-cost, rapid diagnostic solutions. In our previous gene expression studies, we identified peripheral blood leukocyte (PBL) mRNA biomarkers in a non-human primate TB aerosol-challenge model. Here, we describe a study to further validate select mRNA biomarkers from this prior study in new cohorts of patients and controls, as a prerequisite for further development. Whole blood mRNA was purified from ATB patients recruited in the UK and India, LTBI and two groups of controls from the UK (i) a low TB incidence region (CNTRLA) and (ii) individuals variably-domiciled in the UK and Asia ((CNTRLB), the latter TB high incidence regions). Seventy-two mRNA biomarker gene targets were analyzed by qPCR using the Roche Lightcycler 480 qPCR platform and data analyzed using GeneSpring™ 14.9 bioinformatics software. Differential expression of fifty-three biomarkers was confirmed between MTB infected, LTBI groups and controls, seventeen of which were significant using analysis of variance (ANOVA): CALCOCO2, CD52, GBP1, GBP2, GBP5, HLA-B, IFIT3, IFITM3, IRF1, LOC400759 (GBP1P1), NCF1C, PF4V1, SAMD9L, S100A11, TAF10, TAPBP, and TRIM25. These were analyzed using receiver operating characteristic (ROC) curve analysis. Single biomarkers and biomarker combinations were further assessed using simple arithmetic algorithms. Minimal combination biomarker panels were delineated for primary diagnosis of ATB (both PTB and EPTB), LTBI and identifying LTBI individuals at high risk of progression which showed good performance characteristics. These were assessed for suitability for progression against the standards for new TB diagnostic tests delineated in the published World Health Organization (WHO) technology product profiles (TPPs).

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.

Systematic Evaluation of Mycobacterium tuberculosis Proteins for Antigenic Properties Identifies Rv1485 and Rv1705c as Potential Protective Subunit Vaccine Candidates

The lack of efficacious vaccines against Mycobacterium tuberculosis (MTB) infection is a limiting factor in the prevention and control of tuberculosis (TB), the leading cause of death from an infectious agent. Improvement or replacement of the BCG vaccine with one that reliably protects all age groups is urgent.

The lack of efficacious vaccines against Mycobacterium tuberculosis (MTB) infection is a limiting factor in the prevention and control of tuberculosis (TB), the leading cause of death from an infectious agent. Improvement or replacement of the BCG vaccine with one that reliably protects all age groups is urgent. Concerns exist that antigens currently being evaluated are too homogeneous. To identify new protective antigens, we screened 1,781 proteins from a high-throughput proteome-wide protein purification study for antigenic activity. Forty-nine antigens (34 previously unreported) induced antigen-specific gamma interferon (IFN-γ) release from peripheral blood mononuclear cells (PBMCs) derived from 4,452 TB and suspected TB patients and 167 healthy donors. Three (Rv1485, Rv1705c, and Rv1802) of the 20 antigens evaluated in a BALB/c mouse challenge model showed protective efficacy, reducing lung CFU counts by 66.2%, 75.8%, and 60%, respectively. Evaluation of IgG2a/IgG1 ratios and cytokine release indicated that Rv1485 and Rv1705c induce a protective Th1 immune response. Epitope analysis of PE/PPE protein Rv1705c, the strongest candidate, identified a dominant epitope in its extreme N-terminal domain accounting for 90% of its immune response. Systematic preclinical assessment of antigens Rv1485 and Rv1705c is warranted.

Behçet's disease with latent Mycobacterium tuberculosis infection

Objective

The aim of this study is to examine the clinical features of patients with Behçet's disease (BD) in the presence or absence of latent tuberculosis infection (LTBI).

Methods

This was a retrospective study of 232 consecutive patients with active BD hospitalized between October 2012 and June 2017. LTBI was diagnosed based on the positive T-SPOT.TB assay, negative clinical, and imaging examinations.

Results

Among the 232 patients, 68 (29.3%) had LTBI. The frequency, number, and scope of oral ulcers in the BD-LTBI group were significantly more serious than in the non-LTBI group (all P < 0.05). Genital ulcers and eye involvement in the LTBI group were significantly higher than in the non-LTBI group (both P < 0.01). No active TB was diagnosed during follow-up (median, 27.9 months; range, 3-58 months). The patients with LTBI had signs of liver damage compared with the non-LTBI group. In the LTBI group, the frequency of alanine transaminase >2.0, the upper limit of normal, was higher in the rifampicin subgroup compared with the non-rifampicin subgroup (P = 0.033).

Conclusion

Patients with BD and LTBI had worse clinical features than those with BD without LTBI. Rifampicin might be associated with the damage to liver in BD patients combined with latent TB.

Is chemoprophylaxis necessary for all latent tuberculosis infection patients receiving IL-17 inhibitors? A cohort study

The tuberculosis (TB) burden is high in China, with a 32% prevalence of latent tuberculosis infection (LTBI) in Beijing. Screening for LTBI and the chemoprophylaxis of positive patients are recommended prior to biologic therapy. To evaluate the TB-related safety of secukinumab (SEC) in a cohort of plaque psoriasis patients with LTBI receiving different treatments. Plaque psoriasis patients eligible for SEC treatment were screened for TB. LTBI patients (QuantiFeron-TB test positive, QFT+) receiving SEC were closely monitored by chest radiograph, ESR or hs-CRP, and blood counts every 12 to 20 weeks for active TB infection. QFT_patients receiving SEC treatment were screened for LTBI every 6 to 12 months. Of 42 patients treated with SEC, 19 were QFT+ (45.24%). A QFT_patient became QFT+ after 6 months treatment. Two patients started SEC treatment from 2015 to 2016 and were followed up 268 and 216 weeks later, respectively. Three patients received chemoprophylaxis, 17 did not because of safety concerns or being unable to complete the process. During the 16- to 268-week follow-up, no signs of TB reactivation were observed in the 20 LTBI patients receiving SEC. Plaque psoriasis patients with LTBI who received no chemoprophylaxis could be safely treated with SEC.

Tuberculosis infection in children visiting friends and relatives in countries with high incidence of tuberculosis: A study protocol

INTRODUCTION

Tuberculosis (TB) is a global infectious disease. In low-incidence countries, paediatric TB affects mostly immigrant children and children of immigrants. We hypothesize that these children are at risk of exposure to Mycobacterium tuberculosis when they travel to the country of origin of their parents to visit friends and relatives (VFR). In this study, we aim to estimate the incidence rate and risk factors associated to latent tuberculosis infection (LTBI) and TB in VFR children.

METHODS AND ANALYSIS

A prospective study will be carried out in collaboration with 21 primary health care centres (PCC) and 5 hospitals in Catalonia, Spain. The study participants are children under 15 years of age, either immigrant themselves or born to immigrant parents, who travel to countries with high incidence of TB (≥ 40 cases/100,000 inhabitants). A sample size of 492 children was calculated. Participants will be recruited before traveling, either during a visit to a travel clinic or to their PCC, where a questionnaire including sociodemographic, epidemiological and clinical data will be completed, and a tuberculin skin test (TST) will be performed and read after 48 to 72 hours; patients with a positive TST at baseline will be excluded. A visit will be scheduled eight to twelve-weeks after their return to perform a TST and a QuantiFERON-TB Gold Plus test. The incidence rate of LTBI will be estimated per individual/month and person/year per country visited, and also by age-group.

ETHICS AND DISSEMINATION

The study protocol was approved by the Clinical Research Ethics Committee of the Hospital Universitari Mútua Terrassa (code 02/16) and the Clinical Research Ethics Committee of the Fundació Institut Universitari per a la Recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (code P16/094). Articles will be published in indexed scientific journals.

TRIAL REGISTRATION

Clinical-Trials.gov: NCT04236765.

Tuberculosis Skin Test Screening in the National Tuberculosis Program of Trinidad and Tobago

Globally, a quarter of the population is infected with tuberculosis (TB), caused by Mycobacterium tuberculosis. About 5–10% of latent TB infections (LTBI) progress to active disease during the lifetime. Prevention of TB and treating LTBI is a critical component of the World Health Organization’s (WHO) End TB Strategy. This study aims to examine the screening practices for prevention and treatment employed by the National Tuberculosis Program of Trinidad and Tobago in comparison to the WHO’s standard guidelines. A cross-sectional retrospective study was conducted from the TB registers (2018–2019) for persons aged 18 years and above with recorded tuberculin skin test reactions (TST). Bivariate comparisons for categorical variables were made using Chi-square or Fisher’s exact test. Binary logistic regression was used for exploring predictors of TST positivity with adjustment for demographic confounders in multivariable models. Of the total 1972 eligible entries studied, 384 (19.4%) individuals were tested positive with TST. TB contact screening (aOR 2.49; 95% CI 1.65, 3.75) and Bacillus Calmette–Guerin (BCG) vaccination status (aOR 1.66; 95% CI, 1.24 to 2.22) were associated with a positive TST reaction, whereas, preplacement screening failed to show such association when compared to those screened as suspect cases. The findings suggest that TB contact screening and positive BCG vaccination status are associated with TST positivity independent of age and gender.

Serial testing of health care workers for tuberculosis infection: A prospective cohort study

Health Care Workers (HCW) may have an occupational risk of latent tuberculosis infection (LTBI) and TB disease. The objective of this study was to evaluate the performance of the 2-step strategy: tuberculin skin test (TST) followed by confirmation with Interferon (IFN)-γ- release assays (IGRAs) in HCW. A secondary objective was to determine the factors related to conversions and reversions. HCW at risk of occupational exposure who attended the Occupational Department of the Hospital Germans Trias i Pujol were included during the study period (2013-2016). All professionals testing negative for LTBI were included in a cohort study. These workers were followed up with the administration of a TST and an IGRA quantification at least one year after inclusion in the study. Workers with positive TST, regardless of the results of the IGRA tests, were followed-up with an IGRA. 255 workers were enrolled in the study and 108 workers from the same cohort were followed up. During the follow-up period, seven workers presented TST test conversion. One of these conversions was also confirmed by an IGRA test. There were 2 conversions of cases only testing positive with the IGRA. There have been only 2 reversions of cases testing negative with the IGRA. In this study, not all TST conversions were confirmed when using the IGRA test, which highlights the importance of the 2-step strategy. We have detected a low number of conversions and reversions. Our conclusions should be confirmed in studies with a longer follow-up time.

Performance of a household tuberculosis exposure survey among children in a Latin American setting

OBJECTIVE: To evaluate the performance of a survey that quantifies the intensity of household tuberculosis (TB) exposure among children.METHODS: Children aged 0-14 years in Lima, Peru, with ≥1 signs and/or symptoms of TB and a history of contact with an adult TB patient were included. The 10-question survey was administered to caregivers and addressed sleep proximity, frequency of exposure, and infectiousness of the contact. Infection status was determined using tuberculin skin tests (TSTs). The exposure scale was evaluated for association with TST positivity using mixed-effects regression analyses.RESULTS: The exposure score was significantly associated with TST positivity (age-adjusted odds ratio [aOR] 1.14, 95%CI 1.02-1.28). We observed a stronger association with TST positivity in children aged ≤5 years; (aOR 1.23, 95%CI 1.07-1.41) and no association in children 6-14 years of age (aOR 0.99, 95%CI 0.82-1.20).CONCLUSION: This survey was easy to use and modestly successful in predicting TST positivity in children aged ≤5 years. It may be a useful resource for clinicians for diagnosing TB in children, and for national TB programs aiming to scale up preventive therapy initiatives.

How are high burden countries implementing policies and tools for latent tuberculosis infection? A survey of current practices and barriers

BACKGROUND AND AIMS

Despite the World Health Organization (WHO)'s updated guidelines on tuberculosis (TB) preventive treatment, the scale-up of TB preventive therapy remains low in many high-burden countries (HBCs). We conducted a survey to better understand the current status of policy implementation and barriers for scale-up.

METHODS

Survey questions pertained to HBCs' current latent TB infection (LTBI) screening and treatment strategies, and the availability of LTBI tests and newer treatments (eg, isoniazid/rifapentine [3HP]). The 19-question survey was piloted and sent out via email in June 2019 as a protected Microsoft Word document to contacts [National TB Program (NTP) staff, researchers, and health officials] in the 30 TB HBCs. Responses were accepted until February 2020.

RESULTS

Thirty-seven completed surveys from 24 HBCs were received. Respondents from five countries (Brazil, Lesotho, Mozambique, Russia, Zambia) reported having LTBI guidelines that are fully implemented. Among respondents who indicated their country currently has no LTBI guideline implementation (Angola, China, DRC, India, Indonesia, Kenya, Myanmar), the most often cited barrier to implementation was the prioritization of active TB over LTBI management (n = 5, Angola, China, DRC, India, Kenya). Of the 16 countries in which respondents reported using purified protein derivative (PPD), 9 reported having experienced a PPD shortage within the past year (from time of survey). Respondents from six countries reported currently using Interferon-gamma Release Assays (IGRAs) in their NTP, and 13 cited high cost as a barrier to IGRA use. Lastly, rifapentine was stated not be available in 8 HBCs.

CONCLUSION

This survey indicates limited implementation of WHO LTBI guidelines in HBCs and provides some insight into barriers to implementation, including shortage of products (eg, PPD), high costs (eg, IGRAs), and lack of regulatory approval of newer treatments (eg, rifapentine). Thus, we should work towards price reductions for LTBI tests and treatments, and the development of tests that can be more easily implemented at peripheral healthcare levels.

Cost-effectiveness of 3 months of weekly rifapentine and isoniazid compared with other standard treatment regimens for latent tuberculosis infection: a decision analysis study

Background

Latent tuberculosis infection (LTBI) is a critical driver of the global burden of active TB, and therefore LTBI treatment is key for TB elimination. Treatment regimens for LTBI include self-administered daily isoniazid for 6 (6H) or 9 (9H) months, self-administered daily rifampicin plus isoniazid for 3 months (3RH), self-administered daily rifampicin for 4 months (4R) and weekly rifapentine plus isoniazid for 3 months self-administered (3HP-SAT) or administered by a healthcare worker as directly observed therapy (3HP-DOT). Data on the relative cost-effectiveness of these regimens are needed to assist policymakers and clinicians in selecting an LTBI regimen.

Objectives

To evaluate the cost-effectiveness of all regimens for treating LTBI.

Methods

We developed a Markov model to investigate the cost-effectiveness of 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H for LTBI treatment in a cohort of 10000 adults with LTBI. Cost-effectiveness was evaluated from a health system perspective over a 20 year time horizon.

Results

Compared with no preventive treatment, 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H prevented 496, 470, 442, 418, 370 and 276 additional cases of active TB per 10000 patients, respectively. All regimens reduced costs and increased QALYs compared with no preventive treatment. 3HP was more cost-effective under DOT than under SAT at a cost of US$27948 per QALY gained.

Conclusions

Three months of weekly rifapentine plus isoniazid is more cost-effective than other regimens. Greater recognition of the benefits of short-course regimens can contribute to the scale-up of prevention and achieving the 'End TB' targets.

Tumor Necrosis Factor-Alpha Antagonist Interferes With the Formation of Granulomatous Multinucleated Giant Cells: New Insights Into Mycobacterium tuberculosis Infection

More than half of tuberculosis cases in the world are due to resuscitation of dormant Mycobacterium tuberculosis (Mtb) sequestered into cell-derived structures called granulomas. It is fairly admitted that cytokines and more particularly Tumor Necrosis Factor (TNF)-α is critical in the control of Mtb infections and that anti-TNF-α drugs constitute one of the main risk factors for reactivation of latent Mtb infection. The aim of this study was to evaluate the role of etanercept, a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human p75 TNF receptor linked to the Fc portion of human IgG1, in an in vitro model of human tuberculous granuloma. We showed that etanercept slightly delayed the formation of granuloma and reduced the generation of multinuclear giant cells (MGCs). In addition, etanercept exacerbated the expression of M1 polarization genes but also induced interleukin (IL)-10 release. In addition, our results indicated that etanercept inhibited cell fusion in an IL-10-dependent manner. Moreover, adalimumab, a human monoclonal anti-TNF-α IgG1 inhibited MGC formation in granuloma, without altering IL-10 secretion and induced macrophage apoptosis. Taken together, our data provides new insights into the role of TNF-α blockers in MGCs formation and the impact of such immunomodulatory drugs on tuberculous granuloma maturation.

A longitudinal study on latent TB infection screening and its association with TB incidence in HIV patients

Latent TB infection (LTBI) in HIV patients, its treatment, and immunological recovery following highly active antiretroviral therapy (HAART) could interact and impact TB disease progression. We aim to examine the factors associated with LTBI and TB disease development among HIV patients. Longitudinal clinical and laboratory data were accessed from the largest HIV specialist clinic in Hong Kong, where HAART and yearly LTBI screening are routinely provided for HIV patients. Between 2002 and mid-2017, among 2079 HIV patients with 14119 person-years (PY) of follow-up, 32% of LTBI screened patients (n = 1740) were tested positive. The overall TB incidence was 1.26/100 PY from HIV diagnosis to HAART initiation, falling to 0.37/100 PY. A lower risk of TB disease progression was associated with local residence, Chinese ethnicity, negative baseline LTBI result, being on HAART, LTBI treatment, higher baseline CD4 and CD4/CD8 ratio. A positive test at baseline, but not subsequent testing results, was significantly associated with TB disease development. Baseline LTBI screening is an important strategy for identifying HIV patients at risk of TB disease progression. Routine repeat LTBI screening on an annual basis might not give additional benefits to patients on HAART with good immunological responses. Such practice should require re-evaluation.

Diagnosis and management of latent tuberculosis infection in Asia: Review of current status and challenges

Asia has the highest burden of tuberculosis (TB) and latent TB infection (LTBI) in the world. Optimizing the diagnosis and treatment of LTBI is one of the key strategies for achieving the WHO 'End TB' targets. We report the discussions from the Asia Latent TubERculosis (ALTER) expert panel meeting held in 2018 in Singapore. In this meeting, a group of 13 TB experts from Bangladesh, Cambodia, Hong Kong, India, Indonesia, Malaysia, Myanmar, the Philippines, Singapore, Taiwan, Thailand and Vietnam convened to review the literature, discuss the barriers and propose strategies to improve the management of LTBI in Asia. Strategies for the optimization of risk group prioritization, diagnosis, treatment, and research of LTBI are reported. The perspectives presented herein, may help national programs and professional societies of the respective countries enhance the adoption of the WHO guidelines, scale-up the implementation of national guidelines based on the regional needs, and provide optimal guidance to clinicians for the programmatic management of LTBI.

Delay in tuberculosis diagnosis and treatment in Amhara state, Ethiopia

Background

Delayed presentation is a major problem contributing to the high burden and transmission of tuberculosis (TB) in developing countries. The delay may be due to patient delay if the patient visits health-facility for diagnosis after the onset of symptoms of more than 3 weeks or health system delay if the patient is not diagnosed and treated at the time of the first visit. Ethiopia, where no more than two-thirds of TB cases are detected is no exception. Therefore, the aim of this study was to assess delay in diagnosis of tuberculosis among patients taking anti-TB treatment in North Shoa Zone, Ethiopia.

Methods

Institution based cross-sectional study was conducted from 01 to 30 December 2017. All TB patients who took their treatment in the health facilities of the seven selected districts of North Shoa Zone were included. Data was entered into EPI INFO version 3.5.1 statistical software and transferred into SPSS version 20.0 for further analysis. Bivariate and multivariate analysis was used to identify associated factors for delayed TB diagnosis.

Results

Out of 170 tuberculosis patients included, 162 patients were studied with a response rate of 95.3%. The proportion of tuberculosis patients who had delayed diagnosis was 59.9%. The mean time of health-seeking after developing the symptom of tuberculosis was 7.6 weeks. Tuberculosis patients with extra pulmonary site involvements were about four times more likely to be delayed in seeking health services (OR: 4.00, 95% CI: 1.77–9.03) as compared to patients with pulmonary TB. New patients were about three times more likely to come lately for TB diagnosis (OR: 2.94, 95% CI: 1.26–6.84) as compared to patients who had previous-history of treatment. Patients who had no information about TB before they started TB treatment were also around three times to be delayed (OR: 3.37, 95% CI: 1.43–8.00) as compared to those who had the information.

Conclusions

More than 50% of TB patients reported in health-seeking relatively a longer time. Strengthening the health education activities for the community about tuberculosis and capacity building of the health care provider to increase suspicion of identifying tuberculosis and early diagnosis is crucial.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-4056-7) contains supplementary material, which is available to authorized users.

Comparative sensitivity of the test with tuberculosis recombinant allergen, containing ESAT6-CFP10 protein, and Mantoux test with 2 TU PPD-L in newly diagnosed tuberculosis children and adolescents in Moscow

BACKGROUND

A group of Russian scientists has developed Diaskintest, which comprises Mycobacterium tuberculosis-specific recombinant proteins CFP10-ESAT6, for skin testing (0.2 μg/0.1 ml).

STUDY PURPOSE

To evaluate the comparative sensitivity of TST with 2 TU PPD-L and a skin test with tuberculous recombinant allergen (Diaskintest) containing the ESAT6-CFP10 protein in children and adolescents with newly diagnosed active tuberculosis during mass screening in the primary medical service in Moscow.

MATERIALS AND METHODS

The trial was a comprehensive retrospective group study of children and adolescents diagnosed in Moscow with active tuberculosis in 2013-2016, aged 0 to 17 years inclusive.

RESULTS

From 441 patients selected for analysis 408 patients had both tests (TST with 2 TU PPD-L and Diaskintest) performed, in 193 patients both tests were given simultaneously, of them 162 patients were BCG-vaccinated. Comparative results of both tests in 408 patients with tuberculosis: at cut-off ≥ 5 mm, both tests has similar sensitivity: Diaskintest 98.3% (95% CI 97.0-99.6%), TST 98.0% (95% CI 96.7-99.4%), at cut-off ≥10 mm, the sensitivity decreases for both tests: Diaskintest 90.0% (95% CI 87.0-93.0%), TST 88.7% (95% CI 85.6-91.9%), but at cut-off ≥ 15 mm, the decrease in sensitivity is statistically significant: for Diaskintest 61.5% (95% CI 56.7-66.3%), and for TST 46.3% (95% CI 41.4-51.3%), p <0.0001. The results of simultaneous setting of tests on different hands in 193 people (including 162 BCG-vaccinated), do not differ from the results for 408 people. The correlation between the results of Diaskintest and TST was significant in all groups.

CONCLUSION

In children and adolescents with active tuberculosis, Diaskintest of 0.2 μg/ml and the Mantoux test with 2 TU PPD-L have high sensitivity (98%) at a cut-off of 5 mm; however, at cut-off ≥ 15 mm sensitivity is significantly reduced, and the decrease is more pronounced in the Mantoux test. The advantage of Diaskintest is that, unlike the Mantoux test, it has high specificity under the conditions of mass BCG vaccination. The test is simple to carry out, and can be used in mass screening.

Potential effect of household contact management on childhood tuberculosis: a mathematical modelling study

BACKGROUND

Tuberculosis is recognised as a major cause of morbidity and mortality in children, with most cases in children going undiagnosed and resulting in poor outcomes. Household contact management, which aims to identify children with active tuberculosis and to provide preventive therapy for those with HIV or those younger than 5 years, has long been recommended but has very poor coverage globally. New guidelines include widespread provision of preventive therapy to children with a positive tuberculin skin test (TST) who are older than 5 years.

METHODS

In this mathematical modelling study, we provide the first global and national estimates of the impact of moving from zero to full coverage of household contact management (with and without preventive therapy for TST-positive children older than 5 years). We assembled data on tuberculosis notifications, household structure, household contact co-prevalence of tuberculosis disease and infection, the efficacy of preventive therapy, and the natural history of childhood tuberculosis. We used a model to estimate households visited, children screened, and treatment courses given for active and latent tuberculosis. We calculated the numbers of tuberculosis cases, deaths, and life-years lost because of tuberculosis for each intervention scenario and country.

FINDINGS

We estimated that full implementation of household contact management would prevent 159 500 (75% uncertainty interval [UI] 147 000-170 900) cases of tuberculosis and 108 400 (75% UI 98 800-116 700) deaths in children younger than 15 years (representing the loss of 7 305 000 [75% UI 6 663 000-7 874 000] life-years). We estimated that preventing one child death from tuberculosis would require visiting 48 households, screening 77 children, giving 48 preventive therapy courses, and giving two tuberculosis treatments versus no household contact management.

INTERPRETATION

Household contact management could substantially reduce childhood disease and death caused by tuberculosis globally. Funding and research to optimise its implementation should be prioritised.

FUNDING

UK Medical Research Council, US National Institutes of Health, Fulbright Commission, Janssen Global Public Health.