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

Relevance of antigen-induced IL-6 and mitogen-induced or spontaneous IFN-γ secretions in whole blood cultures for detection of Mycobacterium tuberculosis infection and disease

For an effective control of tuberculosis (TB), there is a persistent need for biomarkers that can report true estimates of TB infection (TBI) and predict its progression towards active TB disease. We investigated whether the cell-mediated immune responses to Mycobacterium tuberculosis (Mtb) antigens could provide such biomarkers. The study subjects (n = 174) comprised a cohort of smear-positive, drug-sensitive, HIV-negative pulmonary TB patients (n = 54) and their household contacts (HC, n = 120). Whole blood cultures, in the presence or absence of Mtb antigens- membrane (MtM), purified protein derivative (PPD) and alpha-crystallin (Acr), or the mitogen PHA were subjected to determinations, by flow cytometry, for T cell proliferative and, by ELISA, for IFN-γ, TNF-α, and IL-6 cytokine responses. Additionally, serum levels of the three cytokines were also estimated. The strongest cell-proliferative and cytokine responses were induced by MtM and IL-6 was the most abundantly produced cytokine. While none of the responses induced by Mtb antigens or the serum cytokines levels could discriminate between TB and HC, the ex vivo cytokine responses induced by PHA or 'spontaneously' could apparently do so. The concentrations of IFN-γ induced by PHA in TB blood cultures were significantly lower than in HC cultures (AUC = 0.72). Conversely, the spontaneous IFN-γ or TNF-α secretions in TB cultures were significantly higher than in HC cultures (AUC = 0.66). Our results suggest that IL-6 responses to MtM could be a sensitive indicator of TBI, and low levels of PHA-induced or high levels of spontaneous IFN-γ secretions in HC blood cultures may indicate a progressive infection.

Cost-effective chemiresistive biosensor with MWCNT-ZnO nanofibers for early detection of tuberculosis (TB) lipoarabinomannan (LAM) antigen

The development of an affordable chemiresistive biosensor enhanced with a multi-walled carbon nanotube-zinc oxide (MWCNT-ZnO) nanofiber composite is presented. The sensor leverages the precise interaction between lipoarabinomannan (LAM) tuberculosis (TB) antigens and antibodies to achieve high sensitivity and specificity. The MWCNT-ZnO nanofibers have a larger surface area and better electrical conductivity, which makes it easier for TB antibodies to stick to them. The binding of LAM TB antigens to the fixed Monoclonal Antibody-MBS320597 induces significant resistance changes in the chemiresistive sensor, enabling accurate TB detection. Performance evaluation reveals a linear detection range from 1.0 to 100.0 pg/mL in the lower concentration range and up to 6.0 ng/mL in the higher concentration range, with a sensitivity of 79.750 mA pg mL-1 cm-2 and a lower limit of detection of 40.54 fg/mL. The sensor exhibits a response time of 102 s. Featuring rapid response time and high sensitivity, this biosensor is ideally suited for point-of-care (PoC) applications. The incorporation of MWCNT-ZnO nanofibers shows great potential for enhancing the development of sensitive and cost-effective TB diagnostic tools, which could play a crucial role in advancing global TB control and management efforts.

Elucidating the effect of pro and anti-inflammatory recombinant cytokines TNF-α and TGF-β in tuberculosis

Tuberculosis (TB) is a leading cause of death caused by Mycobacterium tuberculosis (M tb) and about one-third of the world's population is infected with TB. The household contacts of TB patients are at higher risk towards TB than general population. During the initial stages of infection, pro and anti-inflammatory cytokines are induced by innate immune cells, and the course of infection is influenced by general cytokine environment. These cytokines play an important role in the regulation of host immune responses against M tb. Therefore, it is necessary to understand the cytokines role in the immune mechanism to evaluate the correlation between the disease and the immune responses involved in TB. Our current study has focused on recombinant cytokines to understand their effects on cell proliferation and cytokine levels in culture supernatants. We observed that the mean proliferative responses to recombinant rhTNF-α were high and TNF-α levels were significantly low in APTB patients compared to their HHC and HC with p < 0.0375 and p < 0.0051 respectively. The mean proliferative responses to recombinant rhTGF-β were significantly low in APTB when compared to HHC and HC with p < 0.0376, p < 0.0247 respectively, and TGF-β levels were also significantly low in APTB and HHC compared to HC with p < 0.0468 and p < 0.0001 respectively. The lower cytokine secretions in culture supernatants might be due the autocrine signaling by recombinant cytokines towards the inflammatory response. Further, to validate these recombinant cytokines, a larger sample size could aid in identifying individuals at high risk for TB.

Nutritional Supplementation in Tuberculosis Treatment: A Mixed Methods Study of Clinical Outcomes and Patient Perceptions in Jamnagar, India

BACKGROUND

Tuberculosis (TB) remains a significant global health challenge, with malnutrition being a key risk factor for poor outcomes. This study aimed to evaluate the impact of nutritional supplementation on treatment outcomes in drug-sensitive pulmonary tuberculosis (DS-PTB) patients and explore patient perspectives on nutrition during TB treatment.

METHODS

We conducted a mixed methods study in the Jamnagar district of Gujarat, India. The quantitative component was a retrospective cohort study comparing 645 DS-PTB patients who received nutritional supplements with 645 patients who did not. The primary outcomes were cure rates, mortality, and weight gain. Qualitative data were collected through in-depth interviews of 240 patients to explore their experiences and perceptions regarding nutrition during TB treatment.

RESULTS

Patients receiving nutritional supplements had significantly higher cure rates (482/645, n=74.7% vs 328/645, n=50.9%, OR: 2.86, 95% CI: 2.26-3.61, p<0.001) and lower mortality (7/645, n=1.1% vs 37/645, n=5.7%, OR: 0.18, 95% CI: 0.08-0.41, p<0.001) compared to the non-supplemented group. The group that received nutritional supplementation showed greater weight gain over six months (6.5 kg vs 3.1 kg, p<0.001). Qualitative findings revealed that patients who received nutritional supplementation reported improved appetite, increased energy, and faster symptom resolution while control group participants faced financial constraints and reduced appetite as barriers to adequate nutrition.

CONCLUSION

Nutritional supplementation significantly improved treatment outcomes in DS-PTB patients, including higher cure rates, reduced mortality, and enhanced weight gain. Patient perspectives highlighted the multifaceted impact of nutritional support. These findings suggest that integrating nutritional supplementation into standard TB care could substantially improve patient outcomes and experiences.

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.

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.

Infectious optic neuropathy (ION), how to recognise it and manage it

Optic neuropathy can be of infectious or non-infectious/idiopathic aetiology. Many infectious organisms can cause optic neuropathy that can be of varied presentation including papillitis, retrobulbar optic neuritis, neuroretinitis, and optic perineuritis. Detailed history, ocular, systemic/neurologic examination along with appropriate laboratory evaluation can help clinicians to identify the infectious agent causing optic neuropathy. In spite of recent advanced techniques in serological testing and molecular diagnostics like polymerase chain reaction (PCR), the identification of these pathogens is still a diagnostic challenge. It is ideal to have an infectious disease (ID) consultant in the management team, as most of these infections are multisystem involving diseases. Most infectious agents can be effectively treated with specific antibiotics, with or without corticosteroid therapy, but visual recovery is highly variable and depends entirely on early diagnosis of the causative agent. This review article will provide an overview of common pathogens involved in ION and will describe their management paradigms.

Evaluation of Diagnostic Methods and Rifampicin Resistance in Pulmonary Tuberculosis: A Hospital-Based Study

Background Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis, predominantly affecting the lungs (pulmonary TB) and is a significant public health challenge in India. The study aims to analyze demographic, radiological, and clinical subgroups of pulmonary TB cases, examine the relationship between smear acid-fast bacillus (AFB examination) and cartridge-based nucleic acid amplification test (CBNAAT), evaluate CBNAAT sensitivity for Mycobacterium tuberculosis (MTB) in new and previously treated patients, and determine the proportion of rifampicin resistance. Methods This hospital-based prospective study was conducted among patients diagnosed with pulmonary TB at the Respiratory Medicine Department of a Government Hospital over 16 months (August 2019 to December 2020). The study included 150 diagnosed TB cases (new and previously treated). Data collection encompassed demographic details, clinical symptoms, comorbidities, radiological findings (chest X-ray), and microbiological results (smear AFB examination, CBNAAT). Sputum samples were subjected to Ziehl-Neelsen staining and CBNAAT for MTB detection and rifampicin resistance testing. Statistical analysis was performed using IBM SPSS Statistics version 21.0 (IBM Corp., Armonk, NY, USA). Results Of the 150 patients, 69.3% were male, and 48% were aged 21-40 years. The majority had a BMI of 18.5-24.9 kg/m² (50%) and resided in urban areas (63.3%). Common symptoms included cough (95.3%), fever (80%), and weight loss (74%). Cavitary lesions on chest X-ray were observed in 84% of patients. Smear microscopy detected MTB in 72.7% of cases, while CBNAAT detected MTB in 94% of cases. CBNAAT sensitivity for smear-positive and smear-negative samples was 93.97% and 94.12%, respectively. Rifampicin resistance was found in 3% of new cases and 6% of previously treated cases. The sensitivity of smear microscopy was 77.33%, and the sensitivity of CBNAAT was 94%. Conclusion The study underscores the high burden of pulmonary TB and the utility of CBNAAT in detecting MTB and rifampicin resistance, particularly in smear-negative samples. The findings highlight the necessity of universal drug susceptibility testing (DST) for effective TB management and the importance of addressing drug resistance to improve treatment outcomes.

Prevalence of extrapulmonary tuberculosis among people living with HIV/AIDS in Southeast Asia: a systematic review and meta-analysis

The dual burden of human immunodeficiency virus (HIV) and tuberculosis (TB) impacts people living with HIV (PLHIV) coinfected with TB. Although some primary studies have been reported on the burden of extrapulmonary TB (EPTB) among PLHIV in Southeast Asia (SEA), there is no systematic review or meta-analysis that attempts to summarize the available literature. Therefore, this review aims to summarize the prevalence of EPTB/HIV co-infection in SEA using meta-analysis based on a systematic review of published articles and gray literature. A comprehensive 3-stage methodology was adopted to conduct a thorough literature search, encompassing both published and gray literature. Data sources such as MEDLINE and Web of Science were searched for articles reporting data from SEA between 2010 and 2022. Findings were reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines and were sourced using a predefined search strategy from different databases. The Joanna Briggs Institute prevalence studies checklist was employed for critical appraisal. The meta-analysis of proportions was carried out using the "metaprop" function in R software (version 4.3.1) to generate pooled estimates. Effects were summarized using random-effects models, and sources of heterogeneity were explored through I2, utilizing subgroup and sensitivity analyses. Publication bias was assessed using funnel plots and pertinent statistical tests, including Egger's regression analysis. A total of 474 studies were initially identified in our search. After the removal of duplicates and a meticulous screening process of titles and abstracts, along with the application of exclusion criteria, 22 studies comprising 34,740 PLHIV were included in the final meta-analysis. The summary effect or pooled proportion estimate of EPTB among PLHIV was found to be 18% [95% confidence interval (CI): 15,22; heterogeneity: τ2=0.0056; degrees of freedom=21, p<0.001; I2=99%]. Our study showed that there was a diverse range of prevalence of EPTB among PLHIV in the SEA region, which ranged from 5% (95% CI: 4.0-7.0) in South Korea to 48% (95% CI: 41.0-55.0) in Thailand. Our systematic review and meta-analysis indicate a notably higher prevalence of EPTB among PLHIV. Early diagnosis of EPTB is crucial to mitigating associated morbidity and mortality. Therefore, a thorough medical history and comprehensive physical examination are imperative in assessing PLHIV, aiming to promptly identify and rule out EPTB. After a diligent evaluation, appropriate diagnostic measures and tailored management strategies should be promptly instituted.

Mixed methods study on latent tuberculosis among agate stone workers and advocacy for testing silica dust exposed individuals in India

The 2021 tuberculosis (TB) preventive treatment guidelines in India included silicosis as a screening group, yet latent TB infection (LTBI) testing for silica-dust-exposed individuals is underemphasized. Focusing on an estimated 52 million silica-dust-exposed workers, particularly agate-stone workers in Khambhat, Gujarat, our study aims to estimate LTBI prevalence, identify predictors, and gather insights from TB and silicosis experts. Employing a sequential explanatory mixed-methods approach, a cross-sectional study involved 463 agate-stone workers aged ≥ 20 years in Khambhat, using IGRA kits for LTBI testing. In-depth interviews with experts complemented quantitative findings. Among agate-stone workers, 58% tested positive for LTBI, with predictors including longer exposure, type of work, and BCG vaccination. Our findings reveal a nearly double burden of LTBI compared to the general population, particularly in occupations with higher silica dust exposure. Experts advocate for including silica-dust-exposed individuals in high-risk groups for LTBI testing, exploring cost-effective alternatives like improved skin sensitivity tests, and shorter TB preventive treatment regimens to enhance compliance. Future research should explore upfront TB preventive treatment for silica-dust-exposed individuals with high LTBI prevalence and optimal exposure duration. This study underscores the urgent need for policy changes and innovative approaches to TB prevention among silica-dust-exposed populations, impacting global occupational health strategies.

HIV Versus the Human Body: A Case Report of an Immunity-Compromised Patient

The immune system is the body's defense system against infection, pathogenic organisms, or foreign bodies. Human immunodeficiency virus (HIV) infection significantly reduces the number of cells involved in the immune system making the infected person prone to a greater number of infections like tuberculosis (TB). HIV infection reduces the CD4 T helper cell count and further replicates within the body. HIV-TB is a major health concern as there is more chance of progression to acquired immunodeficiency syndrome (AIDS) and the emergence of drug-resistant TB. In this case report, we see how the HIV-TB infection affects the body, significantly affecting the morbidity and mortality of the patient.

An Unusual Ocular Manifestation of Disseminated Tuberculosis: Combined Retinal Vascular Occlusion Inducing Acute Loss of Vision

Disseminated tuberculosis (TB) is a life-threatening disease caused by the hematogenous spread of Mycobacterium tuberculosis. Acute loss of vision as a symptom of disseminated TB is uncommon, as per the literature. Uveitis is the most common ocular manifestation of TB, and tubercular retinal arterial or venous occlusion, with or without ocular signs, has been rarely described before. We discuss the case of a 34-year-old truck driver who presented with fever, cough, and sudden painless loss of vision in the right eye. Examination revealed optic neuropathy, as well as central retinal artery and venous occlusion. Investigations showed bilateral miliary shadows on chest X-ray and multiple ring-enhancing brain lesions on MRI brain, consistent with disseminated TB. Anti-tubercular therapy led to clinical improvement. We report this case to highlight the rarity of this condition.

Bridging the Gap: A Strategic Approach to Upscale Knowledge Among Diverse Healthcare Providers for Effective Tuberculosis Management in Gujarat, India

INTRODUCTION

Tuberculosis (TB) remains a global health challenge, particularly in low- and middle-income countries. Knowledge gaps among healthcare providers (HCPs) significantly impact TB management, hindering timely care-seeking and effective interventions.

OBJECTIVE

The primary objective was to assess knowledge gaps among 3086 HCPs engaged in the National Tuberculosis Elimination Program (NTEP) implementation in Gujarat, India. The study provided a platform to develop and implement cadre-specific training modules to address identified knowledge deficiencies and enhance TB management.

METHODOLOGY

The study was conducted in two phases. Phase one was designed as a cross-sectional assessment to identify the knowledge gaps. Phase two involved the development of cadre-specific training modules based on identified deficiencies in the knowledge, crafted with collaboration from an expert panel. The training impact will be evaluated after completion of the training of all cadres through a comprehensive assessment.

RESULTS

Out of 3086 assessed HCPs, 26% scored below the passing benchmark, revealing significant knowledge gaps. The variations were observed among and within the same cadres, with the accredited social health activists (ASHAs) and community health workers showing higher proficiency while pharmacists and medical officers showed lower proficiency. The cadre-specific training modules and training cascade were designed to address these gaps and improve TB-related knowledge and skills.

CONCLUSION

The study underscores the critical need for targeted interventions to address knowledge gaps among HCPs involved in TB control. The customized HCP-specific training programs are recommended to enhance knowledge, improve TB management, and contribute to national TB elimination goals.

Test and treat approach for tuberculosis infection amongst household contacts of drug-susceptible pulmonary tuberculosis, Mumbai, India

Background

Mumbai is one of the most densely populated areas in the world and is a major contributor to the tuberculosis (TB) epidemic in India. A test and treat approach for TB infection (TBI) amongst household contacts (HHC) is part of the national policy for TB preventive treatment (TPT). However, in practice, the use of interferon-gamma release assay (IGRA) tests for infection are limited, and prevalence of TBI in Mumbai is not known.

Methods

We conducted a cross-sectional study among HHCs exposed to persons with microbiologically-confirmed, drug-susceptible pulmonary TB that were notified for antituberculosis treatment in Mumbai, India during September-December, 2021. Community-based field workers made home visits and offered IGRA (QuantiFERON-TB® Gold In-Tube Plus) tests to HHC aged 5 years and older. After ruling out active TB disease, HHC with IGRA-positive test results were referred for TPT. All HHC were monitored for at least 24 months for progression to active TB disease.

Results

Among 502 HHCs tested, 273 (54%) had IGRA-positive results. A total of 254 (93%) were classified as TBI and were eligible for TPT, of which 215 (85%) initiated TPT, and 194 (90%) completed TPT successfully. There was substantial variation in rates of TBI per household. In 32% of households, all HHC (100%) were IGRA positive and in 64% of households >50% of HHC were infected. In all, 22 HHCs (4%; 22/558) were diagnosed with TB disease; of these, five HHC were diagnosed during follow up, of which three were IGRA positive and had no evidence of disease at initial screening but chose not to initiate TPT.

Conclusion

A test and treat strategy for HHC resulted in the detection of a substantial proportion of TBI and secondary TB cases. Home-based IGRA testing led to high participation rates, clinical evaluations, TPT initiation, and early diagnoses of additional secondary cases. A community-focused, test and treat approach was feasible in this population and could be considered for broader implementation.

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.

Tuberculin skin testing and QuantiFERON™-TB Gold Plus positivity among household contacts in Vietnam

SETTING

TB infection (TBI) is diagnosed using the technique-dependent tuberculin skin test (TST) or costly, more accurate interferon-gamma release assays. The TST (⩾10 mm) threshold was indicated by previous research among household contacts in Vietnam, but routine implementation with a different tuberculin reagent showed unexpectedly low TST positivity.

OBJECTIVE

TST (⩾5 mm and ⩾10 mm) results were compared to QuantiFERON™-TB Gold Plus (QFT) results in household contacts during community campaigns in 2020 and 2021.

DESIGN

This was a cross-sectional multi-center implementation study.

RESULTS

Among 1,330 household contacts in 2020, we found a TBI prevalence of 38.6% (QFT), similar to TST ⩾5 mm (37.4%) and higher than TST ⩾10 mm (13.1%). QFT+/TST+ was higher for TST ⩾5 mm (20.7%) than TST ⩾10 mm (9.4%). QFT was not discordant with TST ⩾5 mm (McNemar's test = 0.6, P = 0.5) but was discordant with TST ⩾10 mm (McNemar's test = 263.9, P < 0.01). Older age and Southern region increased odds for positive TST ⩾5 mm and QFT with weaker associations for TST ⩾10 mm. Agreement and discordance were similar in 2021 for 1,158 household contacts.

CONCLUSION

Tuberculin reagents affect TST positivity rates. High TB burden countries should monitor reliability of TBI diagnosis, including tuberculin potency, cold chain, and TST technique to optimize eligibility for TB preventive treatment.