Latent tuberculosis in children: diagnosis and management

Effect of Bacillus Calmette-Guérin vaccination against Mycobacterium tuberculosis infection in children: an updated systematic review and meta-analysis

OBJECTIVES

To update the understanding of the effectiveness of the Bacillus Calmette-Guérin (BCG) vaccine in preventing tuberculosis (TB) infection in children.

METHODS

PubMed, Web of Science, Cochrane, and Embase were searched from their inception to January 12, 2025. Studies were included if they focused on children under 19 years exposed to pulmonary TB, used interferon-gamma release assays (IGRA) for infection assessment, and reported IGRA-positive outcomes for both BCG and non-BCG groups. Pooled estimates were derived using random-effects meta-analysis, with heterogeneity assessed by the I² statistic.

RESULTS

Total 8242 participants were enrolled in 32 studies. The overall protective effectiveness of BCG against infection was 18%, with a relative risk [RR] of 0.82 (95% confidence interval [CI]: 0.73-0.91], I² = 60%). Subgroup analysis revealed a higher effectiveness of 29% (RR = 0.71 [95% CI: 0.62-0.82], I² = 41%) in low-TB incidence areas, while effectiveness was not significant (RR = 0.95 [95% CI: 0.84-1.09], I² = 55%) in high-TB incidence areas.

CONCLUSIONS

BCG vaccination shows protective effectiveness against TB infection, particularly in low-TB incidence areas. Its effectiveness in high-TB incidence areas remains uncertain, underscoring the need for further research to optimize vaccination strategies in these settings.

Diagnosis of latent tuberculosis infection among pediatric household contacts of Iranian tuberculosis cases using tuberculin skin test, IFN- γ release assay and IFN-γ-induced protein-10

BACKGROUND

Although the World Health Organization has recommended the diagnosis and prophylactic treatment of latent tuberculous infection (LTBI) in child household contacts of tuberculosis (TB) cases, the national programs in high-burden TB regions rarely implement adequate screening of this high-risk group, mainly because of resource limitations. We aimed to evaluate the prevalence of LTBI among pediatric household contacts of TB cases in two high-burden provinces in Iran.

METHODS

We conducted a cohort study in children who had been in household contact with a TB index. All subjects were assessed for active TB disease. For LTBI diagnosis, tuberculin skin test (TST) and QuantiFERON®-TB Gold Plus (QFT-Plus) were performed at the time of the index TB case diagnosis, as well as, 3, 12, and 18 months, if the first results were negative. In addition, interferon-γ-induced protein-10(IP-10) concentrations were measured for all participants.

RESULTS

A total of 230 children were enrolled, who had contact with an index TB case. Three contacts were diagnosed with active TB. According to the TST/QFT-Plus results, 104 (45.2%) children were identified with LTBI during our study. Significantly increased IP-10 levels were found in LTBI patients compared to healthy contacts. Accordingly, more than 50% of LTBI contacts and about 10% of healthy contacts were considered as IP-10-positive.

CONCLUSION

This study alarmingly illustrates a high prevalence of LTBI among Iranian children exposed to TB cases. We, therefore, emphasize that the children living in close contact with an infectious TB case should be screened effectively and receive prophylactic therapy.

Evaluation of Interleukin-2 to Detect Active and Latent Tuberculosis among Household Contacts of Pulmonary Tuberculosis Cases

Background: The interferon-gamma release assays (IGRAs) are the most important diagnostic approach to Mycobacterium tuberculosis infection diagnosis. However, they cannot discriminate between latent tuberculosis infection (LTBI) and active tuberculosis (TB). Some recent studies suggested that interleukin-2 (IL-2) response to M. tuberculosis could be utilized as a potential biomarker to discriminate active disease from LTBI. Objectives: The current study aimed at evaluating the potential role of IL-2 to detect both active TB and LTBI among household contacts of patients with pulmonary TB in two TB-endemic regions of Iran. Methods: A total of 650 household contacts of patients with TB were invited to participate in the current study. All subjects were diagnosed on extensive clinical evaluation of active TB and LTBI based on clinical manifestations and laboratory findings. The IGRA test was performed using QuantiFERON®-TB Gold Plus. The serum level of IL-2 was measured using the ELISA Development Kit. Results: A total of 237 household contacts entered the final analysis, including 132 patients with LTBI and three with active TB. In addition, 14 subjects were included as TB controls and 102 as TB-uninfected controls. The serum level of IL-2 was significantly higher in active TB and LTBI patients than TB-uninfected controls. The ROC curve was plotted between active TB and LTBI, revealing that the cutoff point of 25.5 pg/mL identifies the active form with 88.24% sensitivity and 36.36% specificity. Conclusions: The current study indicated that the IL-2 assay could not discriminate between active TB and LTBI with acceptable sensitivity.

Rate of tuberculosis infection in children and adolescents with household contact with adults with active pulmonary tuberculosis as assessed by tuberculin skin test and interferon-gamma release assays

Tuberculosis (TB) infection was evaluated in Brazilian immunocompetent children and adolescents exposed and unexposed (control group) to adults with active pulmonary TB. Both groups were analysed by clinical and radiological assessment, TST, QFT-IT and T-SPOT.TB. The three tests were repeated after 8 weeks in the TB-exposed group if results were initially negative. Individuals with latent tuberculosis infection (LTBI) were treated and tests were repeated after treatment. Fifty-nine TB-exposed and 42 controls were evaluated. Rate of infection was 69·5% and 9·5% for the exposed and control groups, respectively. The exposed group infection rate was 61% assessed by TST, 57·6% by T-SPOT.TB, and 59·3%, by QFT-IT. No active TB was diagnosed. Agreement between the three tests was 83·1% and 92·8% in the exposed and control groups, respectively. In the exposed group, T-SPOT.TB added four TB diagnoses [16%, 95% confidence interval (CI) 1·6-30·4] and QFT-IT added three TB diagnoses (12%, 95% CI 0-24·7) in 25 individuals with negative tuberculin skin test (TST). Risk factors associated to TB infection were contact with an adult with active TB [0-60 days: odds ratio (OR) 6·9; >60 days: OR 27·0] and sleeping in the same room as an adult with active TB (OR 5·2). In Brazilian immunocompetent children and adolescents, TST had a similar performance to interferon-gamma release assays and detected a high rate of LTBI.

Interferon-γ release assay for the diagnosis of latent Mycobacterium tuberculosis infection in children younger than 5 years: a meta-analysis

BACKGROUND

Interferon-γ release assays (IGRAs) have been widely used for the diagnosis of latent and active tuberculosis in adults, but their role in diagnosing latent tuberculosis infection (LTBI) in children younger than 5 years remains unclear.

OBJECTIVE

To evaluate the diagnostic performance of IGRAs for LTBI in children younger than 5 years.

METHODS

We searched the PubMed, EMBASE, Cochrane Library, and Web of Knowledge databases. According to inclusion criteria, the diagnostic studies of IGRAs for LTBI in children younger than 5 years were included. The study quality was assessed using the 14-item Quality Assessment of Diagnostic Accuracy Studies instrument. The Meta-Analyst software was used to analyze the data.

RESULTS

Seven studies (627 patients) were included. Meta-analysis showed that compared with tuberculin skin test (TST), the pooled sensitivity (Sen), specificity (Spe), positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV), negative predictive value (NPV), accuracy and diagnosis odds ratio (DOR), and summary receiver operating characteristic (SROC) curve of QuantiFERON-TB (values in parentheses are 95% confidence intervals) were 0.841 (0.733-0.911), 0.895 (0.861-0.922), 8.046 (5.953-10.876), 0.192 (0.113-0.326), 0.622 (0.527-0.709), 0.970 (0.946-0.983), 0.891 (0.861-0.916), 50.718 (24.201-106.287), and 0.809 respectively. The pooled Sen, Spe, PLR, NLR, PPV, NPV, accuracy, DOR, and SROC curve of T-SPOT.TB test were 0.931 (0.760-0.983), 0.767 (0.684-0.833), 3.947 (2.854-5.459), 0.095 (0.026-0.354), 0.523 (0.398-0.645), 0.977 (0.914-0.994), 0.806 (0.737-0.860), 65.270 (13.463-316.434), and 0.855, respectively.

CONCLUSION

This meta-analysis showed that the sensitivity and specificity of IGRAs were slightly higher than TST and can be used as supporting tools to detect LTBI in children younger than 5 years. The methodological quality of diagnostic test needs to be improved.

50 years of tuberculosis control in India: progress, pitfalls and the way forward

India established the National Tuberculosis Control Project (NTCP) 50 years ago and re-designed it as Revised NTCP (RNTCP) 19 years ago. Tuberculosis (TB) control was beset with obstacles-BCG vaccination was found ineffective in TB control in 1979; human immunodeficiency virus began spreading in India since 1984 with TB as the commonest opportunistic disease; multi-drug resistance was found to be prevalent since 1992. The World Health Organization declared TB as global emergency in 1993. Yet, RNTCP was extended to the whole nation very slowly, taking 13 years from inception. The first objective of RNTCP, namely 85% treatment success has been achieved and case-fatality had dropped by 90%;. Still, TB burden continues to remain huge; about half the cases are not getting registered under RNTCP; pediatric TB is neglected; TB drains national economy of US$ 23 billion annually. Therefore, TB control is in urgent need of re-design and re-invigoration, with additional inputs and system re-organization to cover all such gaps. We highlight the need for Public Health infrastructure under which all vertical disease control projects such as RNTCP should be synergized for better efficiency and for establishing Public Health Surveillance for collecting denominator-based data on incidence and prevalence to guide course corrections. India ought to spend 3 to 5 times more on TB control than at present. Control needs clear epidemiologic definition and measurable parameters for monitoring the level of control over time. TB control is both a measure of, and a means to, socioeconomic development.

Prevention, diagnosis, and treatment of tuberculosis in children and mothers: evidence for action for maternal, neonatal, and child health services

Tuberculosis affected an estimated 8.8 million people and caused 1.4 million deaths globally in 2010, including a half-million women and at least 64 000 children. It also results in nearly 10 million cumulative orphans due to parental deaths. Moreover, it causes 6%-15% of all maternal mortality, which increases to 15%-34% if only indirect causes are considered. Increasingly, more women with tuberculosis are notified than men in settings with a high prevalence of human immunodeficiency virus (HIV), and maternal tuberculosis increases the vertical transmission of HIV. Tuberculosis prevention, diagnosis, and treatment services should be included as key interventions in the integrated management of pregnancy and child health. Tuberculosis screening using a simple clinical algorithm that relies on the absence of current cough, fever, weight loss, and night sweats should be used to identify eligible pregnant women living with HIV for isoniazid preventive therapy or for further investigation for tuberculosis disease as part of services for prevention of vertical HIV transmission. While implementing these simple, low-cost, effective interventions as part of maternal, neonatal, and child health services, the unmet basic and operational tuberculosis research needs of children, pregnant, and breastfeeding women should be addressed. National policy makers, program managers, and international stakeholders (eg, United Nations bodies, donors, and implementers) working on maternal, neonatal, and child health, especially in HIV-prevalent settings, should give due attention and include tuberculosis prevention, diagnosis, and treatment services as part of their core functions and address the public health impacts of tuberculosis in their programs and services.