Comparative performance of QuantiFERON-TB Gold versus skin test with tuberculosis recombinant allergen (Diaskintest) among patients with suspected pulmonary tuberculosis in Russia

Cracking the antigenic code of mycobacteria: CFP-10/ESAT-6 tuberculosis skin test and misleading results

There are different tuberculosis diagnostic tools available that detect an antigen-specific immune response. The present study aims to evaluate the potential of cross-reactive responses of a CFP-10 and ESAT-6 antigen-based TB test using bioinformatics tools. The study found that the presence of the sequences coding for the CFP-10 and ESAT-6 antigens in mycobacterial genomes is not associated with their pathogenicity, and not even consistent within a single species among its strains, which can lead to either false positive or false negative test results. The data that was analyzed included genome assemblies of all available mycobacterial strains obtained from the NCBI Genome database, while the standalone BLAST and tblastn programs were utilized to detect the presence of the CFP-10 and ESAT-6 sequences. The findings revealed that a number of non-pathogenic mycobacteria contained the aforementioned sequences, while some pathogenic mycobacteria did not, indicating that a standard tuberculin skin test should be more preferable for detecting various pathogenic mycobacteria compared to antigen-specific tests. In the Mycobacterium tuberculosis complex (MTBC), the proportion of positive strains varied within individual species, indicating a complex relationship. Among non-tuberculous mycobacteria (NTMB), more than half of the analyzed species did not contain these sequences which is consistent with their non-pathogenicity. Further research is necessary to fully comprehend the relationship between MTBC pathogenicity and the CFP-10 and ESAT-6 sequences. This could lead to a conclusion that a standard tuberculin skin test, although non-specific due to the undefined antigen content, may be able to detect various pathogenic mycobacteria in a more reliable manner than antigen-specific tests.

Is the new tuberculous antigen-based skin test ready for use as an alternative to tuberculin skin test/interferon-gamma release assay for tuberculous diagnosis? A narrative review

In recent years, novel specific Mycobacteria tuberculous (TB) antigen-based skin test (TBST) has become available for clinical use. The mechanism of TBST is similar to the interferon-gamma release assay (IGRA), making it a potential alternative for identifying latent tuberculous infection (LTBI), especially in subjects with history of bacille Calmette-Guérin vaccination. Three different commercial brands have been developed in Denmark, Russia, and China. Clinical studies in the respective countries have shown promising sensitivity, specificity, and safety profile. Some studies attempted to address the applicability of TBST in specific subject groups but the discrepancy in defining LTBI and problematic methodologies undermine the generalisation of the results to other communities across the world. Limited cost-effectiveness studies for TBST have been conducted without exploring the health economics for preventing development of LTBI into active TB. Unlike IGRA, no clinical studies have addressed the correlation of TBST results (magnitude of induration) with the likelihood of development of active TB. Moreover, the different TBSTs are not widely available for clinical use. While TBST is a promising test to overcome the shortcomings of tuberculin skin tests, more clinical data are needed to support its general application globally for the diagnosis of LTBI.

Advances in Diagnostics and Drug Discovery against Resistant and Latent Tuberculosis Infection

Latent tuberculosis infection (LTBI) represents a subclinical, asymptomatic mycobacterial state affecting approximately 25% of the global population. The substantial prevalence of LTBI, combined with the risk of progressing to active tuberculosis, underscores its central role in the increasing incidence of tuberculosis (TB). Accurate identification and timely treatment are vital to contain and reduce the spread of the disease, forming a critical component of the global strategy known as "End TB." This review aims to examine and highlight the most recent scientific evidence related to new diagnostic approaches and emerging therapeutic treatments for LTBI. While prevalent diagnostic methods include the tuberculin skin test (TST) and interferon gamma release assay (IGRA), WHO's approval of two specific IGRAs for Mycobacterium tuberculosis (MTB) marked a significant advancement. However, the need for a specific test with global application viability has propelled research into diagnostic tests based on molecular diagnostics, pulmonary immunity, epigenetics, metabolomics, and a current focus on next-generation MTB antigen-based skin test (TBST). It is within these emerging methods that the potential for accurate distinction between LTBI and active TB has been demonstrated. Therapeutically, in addition to traditional first-line therapies, anti-LTBI drugs, anti-resistant TB drugs, and innovative candidates in preclinical and clinical stages are being explored. Although the advancements are promising, it is crucial to recognize that further research and clinical evidence are needed to solidify the effectiveness and safety of these new approaches, in addition to ensuring access to new drugs and diagnostic methods across all health centers. The fight against TB is evolving with the development of more precise diagnostic tools that differentiate the various stages of the infection and with more effective and targeted treatments. Once consolidated, current advancements have the potential to transform the prevention and treatment landscape of TB, reinforcing the global mission to eradicate this disease.

Research tests for the diagnosis of tuberculosis infection

INTRODUCTION

Despite huge efforts, tuberculosis (TB) is still a major public health threat worldwide, it is estimated that a quarter of the global population is infected by Mycobacterium tuberculosis (Mtb). For controlling TB and reducing Mtb transmission it is fundamental to diagnose TB infection (TBI) as well as the progressors from TBI to disease to identify those requiring preventive therapy. At present, there is no gold standard test for TBI diagnosis although several new methodologies have been attempted.

AREAS COVERED

This review provides an update on the most recent approaches to develop reliable tests to diagnose TBI and progressors from infection to disease. Experimental tests are based on either the direct identification of Mtb (i.e., Mtb DNA upon host cells isolation; Mtb proteins or peptides) or host response (i.e., levels and quality of specific anti-Mtb antibodies; host blood transcriptome signatures).

EXPERT OPINION

The experimental tests described are very interesting. However, further investigation and randomized clinical trials are needed to improve the sensitivity and specificity of these new research-based tests. More reliable proofs-of-concept and simplification of technical procedures are necessary to develop new diagnostic tools for identifying TBI patients and those that will progress from infection to TB disease.

Updated considerations in the diagnosis and management of tuberculosis infection and disease: integrating the latest evidence-based strategies

INTRODUCTION

Tuberculosis (TB) is a leading infectious cause of global morbidity and mortality, affecting nearly a quarter of the human population and accounting for over 10 million deaths each year. Over the past several decades, TB incidence and mortality have gradually declined, but 2021 marked a threatening reversal of this trend highlighting the importance of accurate diagnosis and effective treatment of all forms of TB.

AREAS COVERED

This review summarizes advances in TB diagnostics, addresses the treatment of people with TB infection and TB disease including recent evidence for treatment regimens for drug-susceptible and drug-resistant TB, and draws attention to special considerations in children and during pregnancy.

EXPERT OPINION

Improvements in diagnosis and management of TB have expanded the available options for TB control. Molecular testing has enhanced the detection of TB disease, but better diagnostics are still needed, particularly for certain populations such as children. Novel treatment regimens have shortened treatment and improved outcomes for people with TB. However, important questions remain regarding the optimal management of TB. Work must continue to ensure the potential of the latest developments is realized for all people affected by TB.

Utility of recombinant fusion protein ESAT6-CFP10 skin test for differential diagnosis of active tuberculosis: A prospective study

Background

The recombinant mycobacterium tuberculosis fusion protein ESAT6-CFP10 skin test (ECST) is a novel test for tuberculosis (TB) infection; however, its accuracy in active tuberculosis (ATB) remains uncertain. This study aimed to evaluate the accuracy of ECST in the differential diagnosis of ATB for an early real-world assessment.

Methods

This prospective cohort study recruited patients suspected of ATB in Shanghai Public Health Clinical Center from January 2021 to November 2021. The diagnostic accuracy of the ECST was evaluated under the gold standard and composite clinical reference standard (CCRS) separately. The sensitivity, specificity, and corresponding confidence interval of ECST results were calculated, and subgroup analyses were conducted.

Results

Diagnostic accuracy was analyzed using data from 357 patients. Based on the gold standard, the sensitivity and specificity of the ECST for patients were 72.69% (95%CI 66.8%-78.5%) and 46.15% (95%CI 37.5%-54.8%), respectively. Based on the CCRS, the sensitivity and specificity of the ECST for patients were 71.52% (95%CI 66.4%-76.6%) and 65.45% (95%CI 52.5%-78.4%), respectively. The consistency between the ECST and the interferon-γ release (IGRA) test is moderate (Kappa = 0.47).

Conclusion

The ECST is a suboptimum tool for the differential diagnosis of active tuberculosis. Its performance is similar to IGRA, an adjunctive diagnostic test for diagnosing active tuberculosis.

Clinical trial registration

http://www.chictr.org.cn, identifier ChiCTR2000036369.

Evaluation of ESAT6-CFP10 Skin Test for Mycobacterium tuberculosis Infection among Persons Living with HIV in China

Recent global guidelines recommend Mycobacterium tuberculosis antigen-based skin tests, such as the ESAT6-CFP10 (EC) skin test, as acceptable alternatives to the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube test (QFT). However, the diagnostic value of these tests among persons living with HIV (PLHIV) is unknown. We aimed to assess the diagnostic accuracy of the EC among a cohort of PLHIV in China. We recruited PLHIV in Jiangsu Province, China, to assess sensitivity and specificity of the EC test. Participants were tested with the QFT, TST, and EC skin test. Results were stratified by age, M. tuberculosis BCG vaccination, and CD4 count. The sensitivity and specificity of the EC skin test was assessed using distinct cutoffs of the QFT and TST. Of 350 PLHIV enrolled in the study, 58 (16.6%), 89 (25.4%), and 59 (16.9%) tested positive with the EC test, the QFT, and the TST, respectively. Positivity increased with CD4 count; however, these trends were similar across tests. At a 5-mm cutoff, EC skin test specificity was high (99.6%, 95% confidence interval [CI] 95% CI = 97.7 to 100.0); however, sensitivity was moderate (81.4%; 95% CI = 66.6 to 91.6). After stratifying by BCG, the sensitivity and specificity were 86.4% (95% CI = 65.1 to 97.1) and 99.1% (95% CI = 95.0 to 100.0) among vaccinated PLHIV and 76.2% (95% CI = 52.8 to 91.8) and 100.0% (95% CI = 97.2 to 100.0) among unvaccinated PLHIV, respectively. Among PLHIV, the diagnostic value of the EC skin test remained high, regardless of BCG vaccination or CD4 count. The EC skin test performed comparably to TST and may be a valid alternative diagnostic test to use in settings or populations with high HIV prevalence and BCG vaccination. To our knowledge, this is the first study to evaluate the novel ESAT6-CFP10 skin test among PLHIV. Among 350 PLHIV, the test displayed high specificity and sensitivity, a finding which did not markedly differ based on BCG vaccination and CD4 count.

The definition of tuberculosis infection based on the spectrum of tuberculosis disease

Latent tuberculosis infection was the term traditionally used to indicate tuberculosis (TB) infection. This term was used to define “a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens through tests such as the tuberculin skin test (TST) or an interferon-γ release assay (IGRA) without clinically active TB”. Recent evidence indicates that the spectrum from TB infection to TB disease is much more complex, including a “continuum” of situations didactically reported as uninfected individual, TB infection, incipient TB, subclinical TB without signs/symptoms, subclinical TB with unrecognised signs/symptoms, and TB disease with signs/symptoms. Recent evidence suggests that subclinical TB is responsible for important M. tuberculosis transmission. This review describes the different stages described above and their relationships. It also summarises the new developments in prevention, diagnosis and treatment of TB infection as well as their public health and policy implications.

The evolution from TB infection to disease is now described as a “continuum process”. Understanding of this is important to appreciate what is new on prevention, diagnosis and treatment of TB infection.https://bit.ly/3jauRKA

Tests for tuberculosis infection: landscape analysis

BACKGROUND

Only the tuberculin skin test (TST) and two interferon-γ release assays (IGRAs), QuantiFERON-TB Gold In-Tube and T-SPOT.TB, are currently endorsed by the World Health Organization as tests for tuberculosis (TB) infection. While IGRAs are more specific than the TST, they require sophisticated laboratory infrastructure and are costly to perform. However, both types of tests have limited performance to predict development of active TB. Tests with improved predictive performance and operational characteristics are needed.

METHODS

We reviewed the current landscape of tests for TB infection identified through a web-based survey targeting diagnostic manufacturers globally.

RESULTS

We identified 20 tests for TB infection: 15 in vitro tests and five skin tests. 13 of the in vitro tests are whole-blood IGRAs and 14 use early secreted antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10), with or without additional antigens. 10 of the tests are based on assays other than an ELISA, such as a fluorescent lateral flow assay that requires less manual operation and shorter assay time and hence is more suitable for decentralisation compared with the existing IGRAs. Four of the five skin tests use ESAT-6 and CFP-10 proteins, while the remaining test uses a new antigen that is specific to Mycobacterium tuberculosis complex.

CONCLUSIONS

New tests have the potential to improve accuracy, operational characteristics and end-user access to tests for TB infection. However, published data in various populations and settings are limited for most new tests. Evaluation of these new tests in a standardised design would facilitate their endorsement and programmatic scale-up.

The diagnostic performance of novel skin-based in-vivo tests for tuberculosis infection compared with purified protein derivative tuberculin skin tests and blood-based in vitro interferon-γ release assays: a systematic review and meta-analysis

BACKGROUND

Novel skin-based tests for tuberculosis infection might present suitable alternatives to current tests; however, diagnostic performance of new tests compared with the purified protein derivative-tuberculin skin test (TST) or interferon-γ release assays (IGRA) needs systematic assessment.

METHODS

In this systematic review and meta-analysis, we searched English (Medline OVID), Chinese (Chinese Biomedical Literature Database and the China National Knowledge Infrastructure), and Russian (e-library) databases from the inception of each database to May 15, 2019, (with updated search of the Russian and English databases on Oct, 20 2020) using terms "ESAT6" OR "CFP10" AND "skin test" AND "Tuberculosis" OR "C-Tb" OR "Diaskintest". We included studies reporting on the performance of index tests alone or compared with a comparator. Inclusion criteria varied according to review objectives and performance outcome, but reporting of test cut-offs for positivity applied to study population was required from all studies. We used a hierarchy of reference standards for tuberculosis infection consistent with the 2020 WHO framework to evaluate diagnostic performance. Two authors independently reviewed the titles and abstracts for English and Chinese (LF and MK) and Russian studies (MK and VN). Study quality was assessed with QUADAS-2. Pooled random-effects estimates are presented when appropriate for total agreement proportion, sensitivity in microbiologically confirmed tuberculosis and specificity in cohorts with low risk of tuberculosis infection. This study is registered with PROSPERO, CRD42019135572.

FINDINGS

We identified 1466 original articles, of which 37 (2·5%) studies, including 10 915 individuals (7111 Diaskintest, 2744 C-Tb, 887 EC, 173 DPPD), were included in the qualitative analysis (29 [78%] studies of Diaskintest, five [15%] studies of C-Tb, two [5%] studies of EC-skintest, and one [3%] study of DPPD). 22 (1·5%) studies including 5810 individuals (3143 Diaskintest, 2129 C-Tb, 538 EC-skintest) were included in the quantitative analysis: 15 (68%) of Diaskintest, five (23%) of C-Tb, and two (9%) of EC-skintest. Tested sub-populations included individuals with HIV, children (0-18 years), and individuals exposed to tuberculosis. Studies were heterogeneous with moderate to high risk of bias. Nine head-to-head studies of index test versus TST and IGRA permitted direct comparisons and pooling. In a mixed cohort of people with and without tuberculosis, Diaskintest pooled agreement with IGRA was 87·16% (95% CI 79·47-92·24) and 55·45% (46·08-64·45) with TST-5 mm cut-off (TST^{5 mm}). Diaskintest sensitivity was 91·18% (95% CI 81·72-95·98) compared with 88·24% (78·20-94·01) for TST^{5 mm}, 89·66 (78·83-95·28) for IGRA QuantiFERON, and 90·91% (79·95-96·16) for TSPOT.TB. C-Tb agreement with IGRA in individuals with active tuberculosis was 79·80% (95% CI 76·10-83·07) compared with 78·92% (74·65-82·63) for TST5 mm/15 mm cut-off (TST^{5 mm/15 mm}). TST^5/15mm reflects threshold in cohorts that applied stratified cutoffs: 5 mm for HIV-infected, immunocompromised, or BCG-naive individuals, and 15mm for BCG-vaccinated immunocompetent individuals. C-Tb sensitivity was 74·52% (95% CI 70·39-78·25) compared with a sensitivity of 78·18% (67·75-85·94) for TST^{5 mm/15 mm}, and 71·67% (63·44-78·68) for IGRA. Specificity was 97·85% (95% CI 93·96-99·25) for C-Tb versus 93·31% (90·22-95·48) for TST 15 mm cut-off and 99·15% (79·66-99·97) for IGRA. EC-skintest sensitivity was 86·06% (95% CI 82·39-89·07).

INTERPRETATION

Novel skin-based tests for tuberculosis infection appear to perform similarly to IGRA or TST; however, study quality varied. Evaluation of test performance, patient-important outcomes, and diagnostic use in current clinical algorithms will inform implementation in key populations.

FUNDING

StopTB (New Diagnostics Working Group) and FIND.

TRANSLATIONS

For the Chinese and Russian translations of the abstract see Supplementary Materials section.

A simple protocol for tuberculin skin test reading certification

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

Adverse Drug Reactions among Children with Tuberculosis in Tashkent, Uzbekistan, 2019

The treatment of childhood tuberculosis can be challenging due to the lack of pediatric drug formulations and monitoring of drug-toxicity in routine settings. There are no published studies from Uzbekistan on the adverse drug reactions (ADR) associated with anti-tuberculosis treatment in children. In this study, we aimed to investigate the ADR associated with anti-tuberculosis treatment in children. This was a cohort study using secondary program data of children treated at the city and regional tuberculosis clinics in Tashkent, Uzbekistan. Of the 302 patients evaluated, 135 (44.7%) reported ADR. New tuberculosis was registered in 277 (92%) patients and 262 (87%) had extrapulmonary tuberculosis. Factors associated with ADR included treatment at a regional hospital (adjusted odds ratio, aOR = 1.75; p = 0.026), female sex (aOR = 2.2; p = 0.004), and treatment with second-line drugs (aOR = 8.82; p < 0.001). The most common ADRs were gastrointestinal disorders (28.5%) followed by hepatitis (8.9%) and dermatologic reactions (8.6%). Most of the ADRs were mild (55.6%) or moderate (43.7%), only one child had severe ADR. Patients with the identified risk factors should be closely monitored during the treatment. We also recommend expansion of ADR surveillance throughout the country for more representative data in the future.

Cost-effectiveness of newer technologies for the diagnosis of Mycobacterium tuberculosis infection in Brazilian people living with HIV

Tuberculosis is the leading cause of death among people living with HIV (PLH). Preventive tuberculosis therapy reduces mortality in PLH, especially in those with a positive tuberculin skin test (TST). New, more specific technologies for detecting latent tuberculosis infection (LTBI) are now commercially available. We sought to analyse the cost-effectiveness of four different strategies for the diagnosis of LTBI in PLH in Brazil, from the Brazilian public health care system perspective. We developed a Markov state-transition model comparing four strategies for the diagnosis of LTBI over 20 years. The strategies consisted of TST with the currently used protein purified derivative (PPD RT 23), two novel skin tests using recombinant allergens (Diaskintest [Generium Pharmaceutical, Moscow, Russia] and EC [Zhifei Longcom Biologic Pharmacy Co., Anhui, China]), and the QuantiFERON-TB-Gold-Plus (Qiagen, Hilden, Germany). The main outcome was cost (in 2020 US dollars) per quality-adjusted life years (QALY). For the base case scenario, the Diaskintest was dominant over all other examined strategies. The cost saving estimate per QALY was US $1375. In sensitivity analyses, the Diaskintest and other newer tests remained cost-saving compared to TST. For PLH, TST could be replaced by more specific tests in Brazil, considering the current national recommendations.

Induration or erythema diameter not less than 5 mm as results of recombinant fusion protein ESAT6-CFP10 skin test for detecting M. tuberculosis infection

Background

Recombinant fusion protein ESAT6-CFP10 (EC) is a newly developed skin test reagent for detecting Mycobacterium tuberculosis (M. tuberculosis) infection. In this study, we evaluated whether induration and erythema could be used as diagnostic indicators for EC skin test to detect M. tuberculosis infection.

Methods

A total of 743 tuberculosis patients and 1514 healthy volunteers underwent an EC skin test. The diameters of induration and erythema were measured with Vernier caliper, 24 h, 48 h, and 72 h after skin testing. Related indicators of EC reagent diagnostic test were tested, and the diagnostic effects of the four diagnostic indicators for EC skin test were compared.

Results

The sensitivity of induration / erythema measurement was lower at 24 h after EC skin test than at 48 h or 72 h (P<0.01). There was no difference in consistency (P = 0.16) between induration with clinical diagnosis, and erythema with clinical diagnosis at 48 h (88.88 and 90.16%, Kappa value was 0.75 and 0.78, respectively). In patients, the sensitivity of erythema measurement was higher than induration measurement (P<0.01). In healthy volunteers, the specificity of erythema measurement was lower than induration at 24 h after skin test, but there was no difference at 48 h after skin test (P = 0.22). In BCG vaccination volunteers, the specificity of induration and erythema were higher than 90%. In addition, there was a high consistency of induration and erythema. When induration or erythema was used as a positive diagnostic indicator, the sensitivity of the EC skin test was improved, and was no different from the other three indicators in terms of specificity and consistency with clinical diagnosis.

Conclusions

Induration or erythema diameter not less than 5 mm could be used as a diagnostic indicator for detecting M. tuberculosis infection.

Trial registration

Phase III clinical trial of recombinant Mycobacterium tuberculosis ESAT6-CFP10 allergen; CTR20150695; registered in December 16, 2015.

An evaluation of liposome-based diagnostics of pulmonary and extrapulmonary tuberculosis

Introduction: Tuberculosis (TB) is still one of the major global health threats and delayed diagnosis or misdiagnosis continues to fuel the global epidemic. The conventional diagnostic approaches have shortcomings that might hinder the process of diagnosis of the disease and ultimately affect the prognosis.Area covered: We emphasize on the process of the synthesis of liposomes, its physicochemical properties affecting the formulation and their utilization in the field of molecular diagnostics for TB. The review also sheds a light on other nanoparticle-based molecular diagnostic approaches for TB. Despite the advent of science, we are yet to have a diagnostic tool that is simple, rapid, sensitive, and specific, and most importantly, one that enables us to demarcate patients with active tuberculosis from those with quiescent lesions, prior vaccination, or other diseases.Expert opinion: The utility of liposomes for diagnostic purposes has been attempted so as to overcome the challenges posed by conventional diagnostic tools for TB. Through this review, we present insights into liposome formulation and selection processes, various studies that report the use of liposome-based diagnostic tools for TB, as well as the limitations associated with the same that can be improvised to make the technology more efficient.

Latent tuberculosis infection in children and adolescents in Russia

BACKGROUND

After the breakup of the Soviet Union, the annual incidence of tuberculosis (TB) in children 15-17 years of age increased in the Russian Federation from 16 per 100 000 population in 1992 to 37 per 100 000 in 2009, and new control measures were implemented.

METHODS

Children were screened annually for TB exposure with a tuberculin skin test (TST) at age 1-8 years. If positive, they were investigated for active TB. If no active TB was found, they were treated with isoniazid for 4-6 months; they then underwent 6-monthly skin tests (which included two recombinant proteins) until negative and annual skin tests thereafter. From the age of 8 years, the yearly follow-up was performed using the skin test that included two recombinant proteins, either until they became negative, developed active TB, or turned 18 years.

RESULTS

The annual incidence of TB in Russian children decreased from 19.1 per 100 000 population in 2001 to 8.3 per 100 000 population in 2018.

CONCLUSIONS

Annual screening for TB exposure with treatment for latent or active TB has reduced the annual incidence of TB in Russian children aged 15-17 years to 1992 levels.