Prevalence and risk factors associated with latent tuberculosis infection among household contacts of smear positive pulmonary tuberculosis patients in South India

Evaluating the cost-effectiveness of Cy-Tb for LTBI in India: a comprehensive economic modelling analysis

BACKGROUND

Latent tuberculosis infection (LTBI) remains a significant challenge, as there is no gold standard diagnostic test. Current methods used for identifying LTBI are the interferon-γ release assay (IGRA), which is based on a blood test, and the tuberculin skin test (TST), which has low sensitivity. Both these tests are inadequate, primarily because they have limitations with the low bacterial burden characteristic of LTBI. This highlights the need for the development and adoption of more specific and accurate diagnostic tests to effectively identify LTBI. Herein we estimate the cost-effectiveness of the Cy-Tb test as compared with the TST for LTBI diagnosis.

METHODS

An economic modelling study was conducted from a health system perspective using decision tree analysis, which is most widely used for cost-effectiveness analysis using transition probabilities. Our goal was to estimate the incremental cost and number of TB cases prevented from LTBI using the Cy-Tb diagnostic test along with TB preventive therapy (TPT). Secondary data such as demographic characteristics, treatment outcome, diagnostic test results and cost data for the TST and Cy-Tb tests were collected from the published literature. The incremental cost-effectiveness ratio was calculated for the Cy-Tb test as compared with the TST. The uncertainty in the model was evaluated using one-way sensitivity analysis and probability sensitivity analysis.

RESULTS

The study findings indicate that for diagnosing an additional LTBI case with the Cy-Tb test and to prevent a TB case by providing TPT prophylaxis, an additional cost of 18 658 Indian rupees (US$223.5) is required. The probabilistic sensitivity analysis indicated that using the Cy-Tb test for diagnosing LTBI was cost-effective as compared with TST testing. If the cost of the Cy-Tb test is reduced, it becomes a cost-saving strategy.

CONCLUSIONS

The Cy-Tb test for diagnosing LTBI is cost-effective at the current price, and price negotiations could further change it into a cost-saving strategy. This finding emphasizes the need for healthcare providers and policymakers to consider implementing the Cy-Tb test to maximize economic benefits. Bulk procurements can also be considered to further reduce costs and increase savings.

Prediction models for Mtb infection among adolescent and adult household contacts in high tuberculosis incidence settings

Tuberculosis household contacts are at high risk of developing tuberculosis. Tuberculosis preventive therapy (TPT) is highly effective, but implementation is hindered by limited accessibility of diagnostic tests aimed at detecting Mycobacterium tuberculosis (Mtb) infection. Development of Mtb infection prediction models to guide clinical decision-making aims to overcome these challenges. We used data from 1905 tuberculosis household contacts (age ≥10 years) from Zimbabwe, Mozambique and Tanzania to develop two prediction models for Mtb infection determined by interferon-gamma release assay (IGRA) using logistic regression with backward elimination and cross-validation and converted these into a risk score. Model performance was assessed using area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity. We developed a basic model with six predictors (age, caregiver role, index case symptom duration, index HIV status, household crowding, and index GeneXpert MTB/Rif results) and a comprehensive model with eleven predictors. The basic and comprehensive risk scores showed limited predictive capability (AUROC 0.592, sensitivity 76%, specificity 35% and AUROC 0.586, sensitivity 76%, specificity 36% respectively), with considerable overlap across IGRA-positive and -negative individuals. Neither model conferred net benefit over a treat-all strategy. Overall, our results suggest that the prediction models developed in this study do not add value for guiding TPT use in high-tuberculosis burden settings. This likely reflects complex Mtb transmission dynamics at the household- and community-level, variation in individual-level susceptibility and immune response, as well as limited accuracy of IGRA testing. Improved diagnostics to determine Mtb infection status in terms of ease-of-use, accuracy, and costs are needed.

Latent Tuberculosis Infection among Household Contacts of Tuberculosis Patients, Healthcare Workers, and Tuberculosis Patients Using QuantiFERON-tuberculosis Gold Plus and Tuberculin Skin Test in a Tertiary Care Hospital Setting Bhubaneswar, Odisha - A Cross-sectional Study

Introduction

Contacts of tuberculosis (TB) patients have an increased risk of latent TB infection (LTBI). Currently, it is diagnosed using one of the two methods: Tuberculin skin test (TST) or QuantiFERON-TB Gold Plus. This study aims to estimate the concordance of TST and QFT-TB Gold Plus and associated factors among 73 healthcare workers (HCWs) and 172 household contacts (HHCs) who came in contact with active TB patients. This study was conducted from January to June 2023.

Methods

Prevalence and agreement were calculated. A regression analysis was performed to assess the predictors of discordance factors.

Results

The prevalence of latent TB was 20.40% (n = 50), defined as a positive result on either test. The overall agreement among participants was 62.04%, with a kappa coefficient of 0.26 (0.16-0.36, 95% confidence interval [CI]) (McNemar, P < 0.001). A higher risk of LTBI was associated with BCG vaccination history, odd ratio 1.63, (95% CI 0.78-3.43) for TST and 0.51 (95% CI 0.22-1.15) for QFT, but this was not significant. Moreover, in our study, only the body mass index of 18.5-25 kg/m2 yielded an odds ratio of 2.33 (95%CI 0.77-6.47) for TST and 1.72 (95% CI 0.48-6.05) for QFT, was significant. Compared with QFT-TB Gold Plus, the sensitivity and specificity of TST were 80.65 (68.63-89.58) and 55.74 (48.22-63.06).

Conclusion

TST exhibited a profound level of agreement with the QFT-Gold Plus assay but showed a higher rate of positivity due to some associated factors among HCWs, HHCs, and TB patients.

Prevalence of Tuberculosis Infection among Various Risk Groups in India: A Systematic Review and Meta-Analysis

Treatment of tuberculosis (TB) infection (TBI) to prevent active TB disease is a key component of the National Strategic Plan to end TB in India, without which the strategies to end TB would be futile. There is a need to rapidly scale up access to effective shorter regimens for tuberculosis preventive treatment (TPT) to a wider set of risk groups. This applies for identifying high-risk groups for TPT expansion. Thus, our aim with this review is to determine the TBI prevalence in different risk groups in India. We searched databases like Embase, Medline, Scopus, and CINAHL for studies published between 2012 and 2023 to estimate TBI in different risk groups in India. The PRISMA guidelines were followed when reviewing the publications, and a predetermined search strategy was used to find relevant sources across various databases. Using MetaXL (MS excel) software, we pooled data based on a random-effects model, along with heterogeneity testing using Cochrane's Q and I2 statistic. A total of 68 studies were included from 10,521 records. TBI pooled prevalence was estimated using the IGRA data, while in the absence of IGRA data, TST data were utilized. The key findings revealed a total of 36% pooled TBI prevalence for all risk factors, 59% among smokers, 53% among diabetics and alcoholics, 48% among malnourished, 47% among contacts of TB patients, 44% among HIV, 36% among pregnant women, 35% among COVID-19 patients, 31% among healthcare workers, 18% among sarcoidosis patients, and 15% among rheumatoid arthritis patients in India. Our review depicted a high TBI burden among groups such as diabetes mellitus, smokers, malnourished, and alcoholics. WHO has yet to recommend for systematic screening and treatment for TBI among these groups for want of evidence which this study provides, highlighting the need to reprioritize the risk groups for tailored TPT strategies.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

DISCUSSION

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

The Yield of Active Tuberculosis Disease and Latent Tuberculosis Infection in Tuberculosis Household Contacts Investigated Using Chest X-ray in Yogyakarta Province, Indonesia

In Indonesia, the implementation of tuberculosis (TB) contact investigation is limited, with low detection rates. We report the yield of and risk factors for TB disease and infection for household contacts (HHCs) investigated using chest X-ray (CXR) screening. We identified HHCs aged five years and above of bacteriologically confirmed index cases from 2018 to 2022 in Yogyakarta City and Kulon Progo. All HHCs were offered screening for TB symptoms; TB infection testing with either tuberculin skin testing or interferon gamma release assay; and referral for CXR. Sputum from those with symptoms or CXR suggestive of TB was tested with Xpert MTB/RIF. Risk factors for active TB disease and latent TB infection (LTBI) were identified by logistic regression models. We screened 2857 HHCs for TB between June 2020 and December 2022, with 68 (2.4%) diagnosed with active TB. Of 2621 HHCs eligible for LTBI investigation, 1083 (45.7%) were diagnosed with LTBI. The factors associated with active TB were age, being underweight, diabetes mellitus, urban living, and sleeping in the same house as an index case. Factors associated with LTBI were increasing age and male gender. Conclusions: Screening for HHC including CXR and TST/IGRA yielded a moderate prevalence of TB disease and infection.

The yield of tuberculosis contact investigation on relapsed TB patients and analysis of associated risk factors: Singapore's experience

The yield of contact investigation on relapsed tuberculosis (TB) cases can guide strategies and resource allocation in the TB control programme. We conducted a retrospective cohort study to review the yield of contact investigation in relapsed TB cases and identify factors associated with TB infection (TBI) among close contacts of relapsed TB cases notified between 2018 and 2022 in Singapore. TB infection positivity was higher among contacts of relapsed cases which were culture-positive for Mycobacterium tuberculosis complex compared to those who were only polymerase chain reaction (PCR)-positive (14.8% vs. 12.3%). On multivariate analysis, after adjusting for age and gender of the index, gender, and existing comorbidities of contacts, factors independently associated with TBI were culture and smear positivity of the index (AOR 1.41, 95%CI 1.02-1.94), higher odds with every 10 years of increase in age compared to contacts below aged 30, contacts who were not Singapore residents (AOR 2.09, 95%CI 1.46-2.97), and household contacts (AOR 2.19, 95%CI 1.44-3.34). Although the yield of screening was higher for those who were culture-positive compared to only PCR-positive relapsed cases, contact tracing for only PCR-positive cases may still be important in a country with moderate TB incidence, should resources allow.

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.

Screening of household contacts for TB infection in Cote d'Ivoire

SETTING

Côte d'Ivoire is a country with a high incidence of TB. The control of TB infection is focused on high-risk patients but has limited implementation.

OBJECTIVE

Cost-benefit analysis of TB infection (TBI) screening of household contacts in Côte d'Ivoire to evaluate economic implications of the implementation of interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST).

DESIGN

We compared the effectiveness of QuantiFERON-TB Gold Plus (QuantiFERON) with the TST using an economic model previously evaluated in medium TB incidence settings. Principal outcomes relating to TBI screening, as well as the lifetime costs and benefits of the patient cohort, were captured using a decision tree, followed by a Markov model.

RESULTS

QuantiFERON proved to be both more effective and less costly than TST. Compared to QuantiFERON, TST use leads to an approximate 33% increase in the lifetime risk of developing active TB.

CONCLUSIONS

For household contacts of active TB cases in Côte d'Ivoire, QuantiFERON is cost-effective when compared with TST. R shiny interactive interface enables model customisation for different scenarios, settings, risk groups and TBI screening methods. Further research should be conducted in similar settings to generalise the results.

Test and Treat Model for Tuberculosis Preventive Treatment among Household Contacts of Pulmonary Tuberculosis Patients in Selected Districts of Maharashtra: A Mixed-Methods Study on Care Cascade, Timeliness, and Early Implementation Challenges

Tuberculosis preventive treatment (TPT) is an important intervention in preventing infection and reducing TB incidence among household contacts (HHCs). A mixed-methods study was conducted to assess the "Test and Treat" model of TPT care cascade among HHCs aged ≥5 years of pulmonary tuberculosis (PTB) patients (bacteriologically/clinically confirmed) being provided TPT care under Project Axshya Plus implemented in Maharashtra (India). A quantitative phase cohort study based on record review and qualitative interviews to understand the challenges and solutions in the TPT care cascade were used. Of the total 4181 index patients, 14,172 HHCs were screened, of whom 36 (0.3%) HHCs were diagnosed with tuberculosis. Among 14,133 eligible HHCs, 10,777 (76.3%) underwent an IGRA test. Of them, 2468 (22.9%) tested positive for IGRA and were suggested for chest X-ray. Of the eligible 2353 HHCs, 2159 (91.7%) were started on TPT, of whom 1958 (90.6%) completed the treatment. The median time between treatment initiation of index PTB patient and (a) HHC screening was 31 days; (b) TPT initiation was 64 days. The challenges in and suggested solutions for improving the TPT care cascade linked to subthemes were tuberculosis infection testing, chest X-ray, human resources, awareness and engagement, accessibility to healthcare facilities, TPT drugs, follow-up, and assessment. A systematic monitoring and time-based evaluation of TPT cascade care delivery followed by prompt corrective actions/interventions could be a crucial strategy for its effective implementation and for the prevention of tuberculosis.

Implementation of tuberculosis preventive therapy with INH-Rifapentine (3HP) for latent tuberculosis infection management in household tuberculosis contacts in India: A prospective study

OBJECTIVE

The primary objective of this study was to ascertain the acceptance, initiation, implementation and treatment completion rates of tuberculosis (TB) preventive therapy (TPT) using 3HP (INH-Rifapentine) among household contacts of microbiologically confirmed drug sensitive TB cases on anti-tubercular treatment under programmatic real-world settings. The secondary objectives were to estimate the prevalence and predictors of latent TB infection (LTBI) in household contacts of the index TB cases. We also ascertained the safety profile of the 3HP TPT regimen in the household contacts.

METHODS

This prospective observational study was conducted at 10 TB chest clinics in Delhi, India during 2022-2023. Household contacts aged 14 and older who tested positive for TB infection on a Tuberculin Skin test were initiated on the 3HP regimen. Logistic regression was performed by including statistically significant independent variables in multiple prediction models. p < 0.05 was considered statistically significant. STATA, version 15.1, was used to compute all analyses.

RESULTS

A total of 1067 (84.68%) eligible contacts of microbiologically confirmed, drug sensitive TB cases underwent screening with tuberculin skin test (TST), 614 (95.6%) LTBI positive contacts accepted the initiation of TPT, and 564 (91.8%) of those initiated on TPT completed the treatment. The major reason for refusal of screening was the lack of perception of risk of TB disease due to asymptomatic status. The prevalence of LTBI positivity through TST was 61.5% (95% CI, 58.5%, 64.4%). Adverse events were reported by 195 (31.8%) contacts initiated on 3HP of which 20 participants discontinued TPT. None of the sociodemographic factors showed a significant association with LTBI positivity (except age) or TPT completion rates.

CONCLUSION

LTBI management with 3HP is feasible among adolescent and adult household contacts in India with high rates of adherence from initiation until treatment completion. The maximum attrition of participants occurred at the time of screening for LTBI using TST.

Outcomes and Challenges in the Programmatic Implementation of Tuberculosis Preventive Therapy among Household Contacts of Pulmonary TB Patients: A Mixed-Methods Study from a Rural District of Karnataka, India

The National TB Elimination Programme (NTEP) of India is implementing tuberculosis preventive treatment (TPT) for all household contacts (HHCs) of pulmonary tuberculosis patients (index patients) aged <5 years and those HHCs aged >5 years with TB infection (TBI). We conducted an explanatory mixed-methods study among index patients registered in the Kolar district, Karnataka during April-December 2022, to assess the TPT cascade and explore the early implementation challenges for TPT provision. Of the 301 index patients, contact tracing home visits were made in 247 (82.1%) instances; a major challenge was index patients' resistance to home visits fearing stigma, especially among those receiving care from the private sector. Of the 838 HHCs, 765 (91.3%) were screened for TB; the challenges included a lack of clarity on HHC definition and the non-availability of HHCs during house visits. Only 400 (57.8%) of the 692 eligible HHCs underwent an IGRA test for TBI; the challenges included a shortage of IGRA testing logistics and the perceived low risk among HHCs. As HHCs were unaware of their IGRA results, a number of HHCs actually eligible for TPT could not be determined. Among the 83 HHCs advised of the TPT, 81 (98%) initiated treatment, of whom 63 (77%) completed treatment. Though TPT initiation and completion rates are appreciable, the NTEP needs to urgently address the challenges in contact identification and IGRA testing.

Plasma CXCL8 and MCP-1 as surrogate plasma biomarkers of latent tuberculosis infection among household contacts-A cross-sectional study

Early detection of latent tuberculosis infection (LTBI) is critical to TB elimination in the current WHO vision of End Tuberculosis Strategy. The study investigates whether detecting plasma cytokines could aid in diagnosing LTBI across household contacts (HHCs) positive for IGRA, HHCs negative for IGRA, and healthy controls. The plasma cytokines were measured using a commercial Bio-Plex Pro Human Cytokine 17-plex assay. Increased plasma CXCL8 and decreased MCP-1, TNF-α, and IFN-γ were associated with LTBI. Regression analysis showed that a combination of CXCL8 and MCP-1 increased the risk of LTBI among HHCs to 14-fold. Our study suggests that CXCL-8 and MCP-1 could serve as the surrogate biomarkers of LTBI, particularly in resource-limited settings. Further laboratory investigations are warranted before extrapolating CXCL8 and MCP-1 for their usefulness as surrogate biomarkers of LTBI in resource-limited settings.

Plasma CXCL8 and MCP-1 as biomarkers of latent tuberculosis infection

Background

Early detection of latent tuberculosis infection (LTBI) is critical to TB elimination in the current WHO vision of End Tuberculosis Strategy.

Methods

We investigated whether detecting plasma cytokines could aid in diagnosing LTBI across household contacts (HHCs) positive for IGRA, HHCs negative for IGRA, and healthy controls. We also measured the plasma cytokines using a commercial Bio-Plex Pro Human Cytokine 17-plex assay.

Results

Increased plasma CXCL8 and decreased MCP-1, TNF-α, and IFN-γ were associated with LTBI. Regression analysis showed that a combination of CXCL8 and MCP-1 increased the risk of LTBI among HHCs to 14-fold.

Conclusions

We postulated that CXCL8 and MCP-1 could be the surrogate biomarkers of LTBI, especially in resource-limited settings.

Prevalence of latent tuberculosis infection in household contacts of pulmonary tuberculosis, time to treat

Treatment of latent pulmonary tuberculosis (TB) in household contacts has been included in the National Tuberculosis Elimination Program to achieve the target of TB elimination by the Government of India by 2025. However, there are no clear estimates of the prevalence of latent TB among the contacts that could suggest the impact of this intervention. The study was conducted to determine the prevalence of and factors predicting latent TB among household contacts with pulmonary TB. All microbiologically confirmed pulmonary TB patients registered between January 2020 and July 2021 and their household contacts were enrolled. All contacts underwent Mantoux testing to determine the prevalence of latent TB. All symptomatic patients also underwent chest radiographs and sputum examinations to diagnose active pulmonary TB. Thereafter, different demographic and clinical factors were evaluated to find predictors of latent TB using a logistic regression model. A total of 118 pulmonary TB cases and their 330 household contacts were enrolled. The prevalence of latent TB and active TB among the contacts was found to be 26.36% and 3.03%, respectively. The female gender of index TB cases was independently associated with a high proportion of latent TB cases in the family (adjusted odds ratio 2.32; 95% confidence interval 1.07-5.05; p=0.03). Neither the higher sputum smear positivity nor the severity of the chest radiograph of index TB cases had any association with the number of contacts being diagnosed as latent TB or active TB. The results showed a significant prevalence of latent TB among household contacts with pulmonary TB. The severity of the disease in the index patient had no association with the prevalence of latent TB.

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

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

The prevalence of tuberculosis infection in India: A systematic review and meta-analysis

Background & objectives

The National Prevalence Survey of India (2019-2021) estimated 31 per cent tuberculosis infection (TBI) burden among individuals above 15 years of age. However, so far little is known about the TBI burden among the different risk groups in India. Thus, this systematic review and meta-analysis, aimed to estimate the prevalence of TBI in India based on geographies, sociodemographic profile, and risk groups.

Methods

To identify the prevalence of TBI in India, data sources such as MEDLINE, EMBASE, CINAHL, and Scopus were searched for articles reporting data between 2013-2022, irrespective of the language and study setting. TBI data were extracted from 77 publications and pooled prevalence was estimated from the 15 community-based cohort studies. Articles were reviewed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines and were sourced using a predefined search strategy from different databases.

Results

Out of 10,521 records, 77 studies (46 cross-sectional and 31 cohort studies) were included. The pooled TBI prevalence for India based on the community-based cohort studies was estimated as 41 per cent [95% confidence interval (CI) 29.5-52.6%] irrespective of the risk of acquiring it, while the estimation was 36 per cent (95% CI 28-45%) prevalence observed among the general population excluding high-risk groups. Regions with high active TB burden were found to have a high TBI prevalence such as Delhi and Tamil Nadu. An increasing trend of TBI was observed with increasing age in India.

Interpretation & conclusions

This review demonstrated a high prevalence of TBI in India. The burden of TBI was commensurate with active TB prevalence suggesting possible conversion of TBI to active TB. A high burden was recorded among people residing in the northern and southern regions of the country. Such local epidemiologic variation need to be considered to reprioritize and implement-tailored strategies for managing TBI in India.

Tuberculosis Infection in Children and Adolescents

The burden of tuberculosis (TB) in children and adolescents remains very significant. Several million children and adolescents are infected with TB each year worldwide following exposure to an infectious TB case and the risk of progression from TB infection to tuberculosis disease is higher in this group compared to adults. This review describes the risk factors for TB infection in children and adolescents. Following TB exposure, the risk of TB infection is determined by a combination of index case characteristics, contact features, and environmental determinants. We also present the recently recommended approaches to diagnose and treat TB infection as well as novel tests for infection. The tests for TB infection have limitations and diagnosis still relies on an indirect immunological assessment of cellular immune response to Mycobacterium tuberculosis antigens using immunodiagnostic testing. It is recommended that TB exposed children and adolescents and those living with HIV receive TB preventive treatment (TPT) to reduce the risk of progression to TB disease. Several TPT regimens of similar effectiveness and safety are now available and recommended by the World Health Organisation.

Strategies to detect and manage latent tuberculosis infection among household contacts of pulmonary TB patients in high TB burden countries - a systematic review and meta-analysis

OBJECTIVE

To summarise latent tuberculosis infection (LTBI) management strategies among household contacts of bacteriologically confirmed pulmonary tuberculosis (TB) patients in high-TB burden countries.

METHODS

PubMed/MEDLINE (NCBI) and Scopus were searched (January 2006 to December 2021) for studies reporting primary data on LTBI management. Study selection, data management and data synthesis were protocol-driven (PROSPERO-CRD42021208715). Primary outcomes were the proportions of LTBI, initiating and completing tuberculosis preventive treatment (TPT). Reported factors influencing the LTBI care cascade were qualitatively synthesised.

RESULTS

From 3694 unique records retrieved, 58 studies from 23 countries were included. Most identified contacts were screened (median 99%, interquartile range [IQR] 82%-100%; 46 studies). Random-effects meta-analysis yielded pooled proportions for: LTBI 41% (95% confidence interval [CI] 33%-49%; 21,566 tested contacts); TPT initiation 91% (95% CI 79%-97%; 129,573 eligible contacts, 34 studies); TPT completion 65% (95% CI 54%-74%; 108,679 TPT-initiated contacts, 28 studies). Heterogeneity was significant (I²  ≥ 95%-100%) and could not be explained in subgroup analyses. Median proportions (IQR) were: LTBI 44% (28%-59%); TPT initiation 86% (60%-100%); TPT completion 68% (44%-82%). Nine broad themes related to diagnostic testing, health system structure and functions, risk perception, documentation and adherence were considered likely to influence the LTBI care cascade.

CONCLUSION

The proportions of household contacts screened, detected with LTBI and initiated on TPT, though variable was high, but the proportions completing TPT were lower indicating current strategies used for LTBI management in high TB burden countries are not sufficient.