Predictive value of a whole blood IFN-gamma assay for the development of active tuberculosis disease after recent infection with Mycobacterium tuberculosis

Declining incidence rate of tuberculosis among close contacts in five years post-exposure: a systematic review and meta-analysis

BACKGROUND

Individuals in close contact with active pulmonary tuberculosis (TB) patients showed a high risk of recent infection and, once infected, higher risk of developing active TB in the following years post-exposure. But the peak time of active disease onset is unclear. This study aims to estimate post exposure TB incidence risk among close contacts to provide reference for clinical and public health strategies.

METHODS

We searched PubMed, Web of Science, and EMBASE for articles published until December 1, 2022. The incidence rates were quantitatively summarized by means of meta-analysis using the random-effect model.

RESULTS

Of the 5616 studies, 31 studies included in our analysis. For baseline close contacts results, the summarized prevalence of Mycobacterium tuberculosis (MTB) infection and active TB was found to be 46.30% (95% CI: 37.18%-55.41%) and 2.68% (95% CI: 2.02%-3.35%), respectively. During the follow-up, the 1-year, 2-year and 5-year cumulative incidence of TB in close contacts were 2.15% (95% CI: 1.51%-2.80%), 1.21% (95% CI: 0.93%-1.49%) and 1.11% (95% CI: 0.64%-1.58%), respectively. Individuals with a positive result of MTB infection testing at baseline showed significantly higher cumulative TB incidence as compared to those negatives (3.80% vs. 0.82%, p < 0.001).

CONCLUSIONS

Individuals with close contact to active pulmonary TB patients are bearing significant risk of developing active TB, particularly within the first-year post-exposure. Population with recent infections should be an important priority for active case finding and preventive intervention worldwide.

Combined Detection of IFN-γ and Lymphocyte Subsets with Activation Indicators in the Clinical Application of Mycobacterium Tuberculosis Infection at Different Times

The immune status of mycobacterium tuberculosis (MTB) infection is essential for the diagnosis and treatment of this disease. In this work, we aim to evaluate the clinical significance of the combination of serum IFN-γ, IGRAs (Interferon-Gamma Release Assay), lymphocyte subset with activation indicators detection in active and latent tuberculosis infection patients. For this study, anticoagulant whole blood were collected from 45 active tuberculosis (AT group), 44 latent tuberculosis (LT group) and 32 healthy controls (HCs group). The serum IFN-γ and IGRAs detected by chemiluminescence, and the percentage of lymphocyte subsets and activated lymphocytes detected by flow cytometry. The results showed combined IGRAs, serum IFN-γ and NKT cells not only has good diagnostic efficiency for the AT, but also provides a laboratory diagnostic method to distinguish AT from LT. Activation indicator of CD3⁺HLA-DR⁺T and CD4⁺HLA-DR⁺T can effectively distinguish LT from HCs. While combined CD3⁺T, CD4⁺T, CD8⁺CD28⁺T, Treg and CD16⁺CD56⁺CD69⁺ cells can distinguish AT from HCs. This study showed combined direct detection of serum IFN-γ and IGRAs as well as lymphocyte subsets with activation indicators which may provide laboratory basis for the diagnosis and differential diagnosis of active and latent MTB infection.

The Interferon-Gamma Release Assay versus the Tuberculin Skin Test in the Diagnosis of Mycobacterium tuberculosis Infection in BCG-Vaccinated Children and Adolescents Exposed or Not Exposed to Contagious TB

BACKGROUND

Children have an increased risk of developing active tuberculosis (TB) after exposure to Mycobacterium tuberculosis (M.tb), and they are more likely to develop the most severe forms of TB. Rapid diagnosis and treatment of latent M.tb infection (LTBI) is essential to lessen the devastating consequences of TB in children.

OBJECTIVE

The aim of the study was to evaluate TST (tuberculin skin test) and IGRA (interferon-gamma release assay) utility in identifying LTBI in a cohort of Bacille Calmette-Guérin (BCG)-vaccinated Polish children and adolescents exposed or not exposed to contagious TB. In addition, we asked whether quantitative assessment of IGRA results could be valuable in predicting active TB disease.

RESULTS

Of the 235 recruited volunteers, 89 (38%) were TST-positive (TST+), 74 (32%) were IGRA-positive (IGRA+), and 62 (26%) were both TST+ and IGRA+. The frequency of TST positivity was significantly higher in the group with (59%) than without TB contact (18%). The percentage of TST+ subjects increased with age from 36% in the youngest children (<2 years) to 47% in the oldest group (>10 years). All positive IGRA results were found solely in the group of children with TB contact. There was a significant increase in the rate of positive IGRA results with age, from 9% in the youngest to 48% in the oldest group. The 10 mm TST cutoff showed good sensitivity and specificity in both TB exposed and nonexposed children and was associated with excellent negative predictive value, especially among nonexposed volunteers. Mean IFN-γ concentrations in IGRA cultures were significantly higher in the group of LTBI compared to the children with active TB disease, both TST+ and TST-.

CONCLUSIONS

Both TST and IGRA can be used as screening tests for BCG-vaccinated children and adolescents exposed to contagious TB.

The value of Xpert MTB/RIF assay of urine samples in the early diagnosis of smear-negative urinary tuberculosis

BACKGROUND

According to reports, between 30 and 40 percent of extrapulmonary tuberculosis (EPTB) cases are caused by urinary tract tuberculosis (UTB). It is critical to identify UTB quickly since it frequently precedes delayed medical attention, which can have detrimental effects. This study examined the use of Xpert MTB/RIF, a PCR test that can detect MTB as well as resistance to an important drug, rifampicin (RIF), in UTB particularly, for the early identification of UTB.

METHODS

180 participants with clinically presumptive UTB whose urine samples were chosen for urine sediment smear, culture, Xpert MTB/RIF, and TB-DNA testing at Henan Chest Hospital between January 2019 and July 2022. Evaluation of test performance using Composite Reference Standards (CRSs). We studied and compared the positivity rate for various tests using the t-test. The effectiveness of smear, culture, Xpert MTB/RIF, and TB-DNA was assessed using McNemar test.

RESULTS

In this subject, a total of 108 participants were diagnosed with UTB, and the positivity rate was 67.1%. Compared with CRS, the positivity rate of Xpert MTB/RIF, smear, culture, and TB-DNA was 29.69% (19/64, P < 0.001), 7.56% (9/119, P < 0.1), 12.12% (4/33, P > 0.05), and 18.75% (6/32, P < 0.1), respectively. The sensitivity of Xpert MTB/RIF assay was significantly better than that of smear and culture tests (78.9% vs. 77.8%, P < 0.05; 78.9% vs. 75%, P < 0.05). Under CRS, the positivity rate for Xpert, culture, and TB-DNA was 31.6% (6/19, P < 0.1), 6.2% (1/16, P > 0.05), and 26.7% (4/15, P > 0.05) for TB-DNA, respectively, compared to smear negative. Xpert MTB/RIF assay specificity was significant for culture and TB-DNA (53.6% vs. 25%, P < 0.01; 53.6% vs. 38.9%, P < 0.05), and Xpert MTB/RIF assay FPV was significant for culture and TB-DNA (53.6% vs. 0%, P < 0.001; 53.6% vs. 0%, P < 0.001).

CONCLUSION

Xpert MTB/RIF outperforms smear, cultures, and TB-DNA in detecting UTB, plus Xpert MTB/RIF is better suited for early diagnosis in smear-negative UTB.

Tuberkulose im Erwachsenenalter

Die Tuberkulose ist in Deutschland eine seltene, überwiegend gut behandelbare Erkrankung. Weltweit ist sie eine der häufigsten Infektionserkrankungen mit ca. 10 Millionen Neuerkrankungen/Jahr. Auch bei einer niedrigen Inzidenz in Deutschland bleibt Tuberkulose insbesondere aufgrund der internationalen Entwicklungen und Migrationsbewegungen eine wichtige Differenzialdiagnose. In Deutschland besteht, aufgrund der niedrigen Prävalenz der Erkrankung und der damit verbundenen abnehmenden klinischen Erfahrung, ein Informationsbedarf zu allen Aspekten der Tuberkulose und ihrer Kontrolle. Diese Leitlinie umfasst die mikrobiologische Diagnostik, die Grundprinzipien der Standardtherapie, die Behandlung verschiedener Organmanifestationen, den Umgang mit typischen unerwünschten Arzneimittelwirkungen, die Besonderheiten in der Diagnostik und Therapie resistenter Tuberkulose sowie die Behandlung bei TB-HIV-Koinfektion. Sie geht darüber hinaus auf Versorgungsaspekte und gesetzliche Regelungen wie auch auf die Diagnosestellung und präventive Therapie einer latenten tuberkulösen Infektion ein. Es wird ausgeführt, wann es der Behandlung durch spezialisierte Zentren bedarf.

Die Aktualisierung der S2k-Leitlinie „Tuberkulose im Erwachsenenalter“ soll allen in der Tuberkuloseversorgung Tätigen als Richtschnur für die Prävention, die Diagnose und die Therapie der Tuberkulose dienen und helfen, den heutigen Herausforderungen im Umgang mit Tuberkulose in Deutschland gewachsen zu sein.

Comparison of interferon gamma release assay and tuberculin skin test for diagnosis of latent tuberculosis in psoriasis patients planned for systemic therapy

Background:

Latent tuberculosis infection (LTBI) is a common yet difficult problem to diagnose in tuberculosis endemic countries. Both tuberculin skin test (TST) and interferon-gamma release assay (IGRA) are used for the diagnosis of LTBI.

Aims:

The aim of the study is to compare TST and IGRA in patients planned for systemic treatment of psoriasis.

Methods:

It was a diagnostic study conducted in a tertiary care centre during the study period from January 20 to December 20. Patients more than 18 years of age with chronic plaque psoriasis planned for systemic therapy were included. Psoriasis area severity index (PASI), history of tuberculosis in past or family and BCG vaccination were recorded. Complete blood count, radiograph of the chest, tuberculin skin test and interferon-gamma release assay were performed in all patients. Statistical analysis was performed using statistical package for social sciences (SPSS version 20, Chicago).

Results:

A total of 75 patients, including 48 males and 27 females, were included in the study. The mean age and mean duration of disease were 46.08 (±12.16) and 4.59 (±3.8) years, respectively. Seventy-one (94.6%) patients had BCG scar, and two (2.6%) had a history of tuberculosis in a family member. The TST and IGRA were positive (>10 mm) in 23 (30.6%) and 16 (21.3%) patients, respectively. Either TST or IGRA was positive in 28 (37.3%) patients. Out of these 28 patients, concordance was seen in 11 (39.2%) and discordance in 17 (60.7%). Discordance was TST+/IGRA − in 12 (42.8%) and TST−/IGRA + in five (17.8%) patients. Abnormality in radiograph of the chest and computed tomography (CT) scan of the chest were seen in five (6.6%) and nine (12%) patients, respectively. The patients with either TST or IGRA + were more likely to have abnormal chest radiographs than those who were TST−/IGRA− (OR: 11.3, 95% CI: 1.24–102.3, P = 0.03). The TST and IGRA showed fair agreement ( = 0.364, P = 0.003). ROC curve was plotted for the absolute value of TST in mm considering IGRA as the gold standard. The area under the curve was 0.805 (95%CI: 0.655–0.954). For the TST positivity cut-off of 10 and 15 mm, specificity was 77.3% and 95.5%, respectively; the sensitivity was 68.8% irrespective of the cut-off value.

Limitation:

Small sample size and lack of follow-up are the biggest limitations of the study. The lack of a gold standard in the diagnosis of LTBI is an inherent yet unavoidable flaw in the study.

Conclusion:

Reactivation of LTBI is a concern in a patient planned for immunosuppressive therapy. We suggest the use of both TST and IGRA rather than two-step testing (TST followed by IGRA) or IGRA alone for the diagnosis of LTBI, especially in patients with a high risk of reactivation. The positivity on either test should prompt further evaluation and treatment decisions should be taken considering the risk-benefit ratio of treatment rather than test results alone.

Transcriptional signatures of human peripheral blood mononuclear cells can identify the risk of tuberculosis progression from latent infection among individuals with silicosis

Host immune factor plays an important role in the progression of latent tuberculosis infection (LTBI) to active tuberculosis (TB) disease. However, whether global gene expression measured in blood biomarkers allows the identification of prospective signatures for TB risk remains unknown. Hence, we aimed to assess the ability of the transcriptome signatures in the human peripheral blood mononuclear cells (PBMCs) of LTBI subjects to differentiate future TB progressors from non-progressors. In a randomized clinical trial of TB preventive treatment of 513 participants with silicosis, we randomly collected PBMC samples from 50 LTBI subjects in the observational group, which was monitored for TB disease progression for 37 months. The prospective signatures of TB risk between the two participants who developed active TB (progressors) and four matched individuals who remained healthy (non-progressors) were compared using differential expression analysis, Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and Weighted Gene Co-expression Network Analysis. The 20 TB-specific differentially expressed genes, which were significantly downregulated in TB progressors, were revealed to be associated with interferon-gamma response-related genes. Therefore, the PBMC transcriptome profiles analyzed in this study may help identify LTBI individuals who are at risk of progressing to active TB among silicosis patients and may provide new insights for targeted intervention to prevent disease progression.

Tuberculosis contact investigation results among paediatric contacts in low-incidence settings in Finland

Tuberculosis (TB) risk is highest immediately after primary infection, and young children are vulnerable to rapid and severe TB disease. Contact tracing should identify infected children rapidly and simultaneously target resources effectively. We conducted a retrospective review of the paediatric TB contact tracing results in the Hospital District of Helsinki and Uusimaa from 2012 to 2016 and identified risk factors for TB disease or infection. Altogether, 121 index cases had 526 paediatric contacts of whom 34 were diagnosed with TB disease or infection. The maximum delay until first contact investigation visit among the household contacts under 5 years of age with either TB disease or infection was 7 days. The yield for TB disease or infection was 4.6% and 12.8% for household contacts, 0.5% and 0% for contacts exposed in a congregate setting and 1.4% and 5.0% for other contacts, respectively. Contacts born in a TB endemic country (aOR 3.07, 95% CI 1.10-8.57), with household exposure (aOR 2.96, 95% CI 1.33-6.58) or a sputum smear positive index case (aOR 3.96, 95% CI 1.20-13.03) were more likely to have TB disease or infection.Conclusions: Prompt TB investigations and early diagnosis can be achieved with a well-organised contact tracing structure. The risk for TB infection or disease was higher among contacts with household exposure, a sputum smear positive index case or born in a TB endemic country. Large-scale investigations among children exposed in congregate settings can result in a very low yield and should be cautiously targeted. What is Known: • Vulnerable young children are a high priority in contact tracing and should be evaluated as soon as possible after TB exposure What is New: • Prompt investigations for paediatric TB contacts and early diagnosis of infected children can be achieved with a well-organised contact tracing structure • Large-scale investigations among children exposed in congregate settings can result in a very low yield and should be cautiously targeted.

Latent Tuberculosis Infection Increases in Kidney Transplantation Recipients Compared With Transplantation Candidates: A Neglected Perspective in Tuberculosis Control

Background

The prevalence and incidence of latent tuberculosis infection (LTBI) in patients with kidney transplantation remain unclear.

Methods

In this prospective study, we enrolled kidney transplantation candidates (KTCs) and recipients (KTRs) from 2014 to 2018. We defined LTBI as a positive result of QuantiFERON-TB Gold In-tube (QFT). We analyzed the predictors for LTBI acquisition and followed up on QFT assay test for 2 years among those initially without LTBI.

Results

Of 425 patients enrolled, 305 (71.8%) patients belonged to the KTC group and 120 (28.2%) to the KTR group. The initial QFT showed positive results in 32 (10.5%) and 24 (20.0%) patients in the KTC and KTR groups, respectively (P = .009). The QFT response value in patients with LTBI was higher in the KTR group than in the KTC group (1.85 vs 1.06 IU/mL, P = .046). Multivariate logistic regression showed that old age, absence of bacillus Calmette–Guérin (BCG) scar, presence of donor-specific antibody, and KTR group were independent factors for positive LTBI. For participants with initial negative QFT, positive QFT conversion within a 2-year follow-up was higher after kidney transplantation (20%) than in KTCs (5.5%) (P = .034).

Conclusions

This study is the first cohort to follow up LTBI status in patients with kidney transplantation and shows its higher prevalence and incidence in KTRs. It indicates that surveillance of LTBI after renal transplantation is important. In addition to status of kidney transplantation, old age, no BCG vaccination, and positive donor-specific antibody are also positive predictors for LTBI.

Predictive value of TNF-α, IFN-γ, and IL-10 for tuberculosis among recently exposed contacts in the United States and Canada

BACKGROUND

We examined cytokine immune response profiles among contacts to tuberculosis patients to identify immunologic and epidemiologic correlates of tuberculosis.

METHODS

We prospectively enrolled 1272 contacts of culture-confirmed pulmonary tuberculosis patients at 9 United States and Canadian sites. Epidemiologic characteristics were recorded. Blood was collected and stimulated with Mycobacterium tuberculosis culture filtrate protein, and tumor necrosis factor (TNF-α), interferon gamma (IFN-γ), and interleukin 10 (IL-10) concentrations were determined using immunoassays.

RESULTS

Of 1272 contacts, 41 (3.2%) were diagnosed with tuberculosis before or < 30 days after blood collection (co-prevalent tuberculosis) and 19 (1.5%) during subsequent four-year follow-up (incident tuberculosis). Compared with contacts without tuberculosis, those with co-prevalent tuberculosis had higher median baseline TNF-α and IFN-γ concentrations (in pg/mL, TNF-α 129 versus 71, P < .01; IFN-γ 231 versus 27, P < .001), and those who subsequently developed incident tuberculosis had higher median baseline TNF-α concentrations (in pg/mL, 257 vs. 71, P < .05). In multivariate analysis, contact age < 15 years, US/Canadian birth, and IFN or TNF concentrations > the median were associated with co-prevalent tuberculosis (P < .01 for each); female sex (P = .03) and smoking (P < .01) were associated with incident tuberculosis. In algorithms combining young age, positive skin test results, and elevated CFPS TNF-α, IFN-γ, and IL-10 responses, the positive predictive values for co-prevalent and incident tuberculosis were 40 and 25%, respectively.

CONCLUSIONS

Cytokine concentrations and epidemiologic factors at the time of contact investigation may predict co-prevalent and incident tuberculosis.

Efficacy and safety of weekly rifapentine and isoniazid for tuberculosis prevention in Chinese silicosis patients: a randomized controlled trial

OBJECTIVE

The aim was to evaluate the efficacy, safety and completion rate of 3-month, once-weekly rifapentine and isoniazid for tuberculosis (TB) prevention among Chinese silicosis patients.

METHODS

Male silicosis patients without human immunodeficiency virus infection, aged 18 years to 65 years, with or without latent TB infection, were randomized 1:1 to receive rifapentine/isoniazid under direct observation (3RPT/INH group) or were untreated (observation group). Active TB incidence was compared between the two groups with 37 months of follow-up. Safety profile and complete rates were evaluated.

RESULTS

A total of 1227 adults with silicosis were screened; 513 eligible participants were enrolled and assigned to 3RPT/INH (n = 254) vs. observation (n = 259). Twenty-eight participants were diagnosed with active TB, and 9 and 19 in the 3RPT/INH group and observation groups, respectively. In the intention-to-treat analysis, the cumulative active TB rate was 3.5% (9/254) in the 3RPT/INH group and 7.3% (19/259) in the observation group (log rank p 0.055). On per protocol analysis, the cumulative active TB rates were 0.7% (1/139) and 7.3% (19/259), respectively (log rank p 0.01). Owing to an unexpected high frequency of adverse events (70.4%) and Grade 3 or 4 AEs (7.9%), the completion rate of the 3RPT/INH regimen was 54.7% (139/254). Twenty-six (10.8%) participants had flu-like systemic drug reactions; five (2.1%) experienced hepatotoxicity.

DISCUSSION

Weekly rifapentine/isoniazid prophylaxis prevented active TB among Chinese people with silicosis when taken, irrespective of LTBI screening; efficacy was reduced by lack of compliance. The regimen must be used with caution because of the high rates of adverse effects.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number: NCT02430259.

Evaluation of QuantiFERON tuberculosis Gold In-Tube assay for diagnosis of active tuberculosis in children

AIM

Tuberculin skin test (TST) is still used in diagnostic algorithms of childhood tuberculosis (TB). QuantiFERON TB Gold In-Tube assay (QFT-GIT) is an alternative test to TST based on the detection of interferon-gamma release upon in vitro induction of peripheral mononuclear cells by TB antigens. In this study, we aimed to determine the diagnostic value and performance of QFT-GIT for active childhood TB.

METHODS

This retrospective study was conducted between January 2005 and December 2011 in three referral hospitals in Turkey with 124 children who were diagnosed with definite active TB. Sensitivity values of TST and QFT-GIT were determined by accepting the microbiological confirmation as the gold standard of diagnosis of TB.

RESULTS

In our study, sensitivity of QFT-GIT and TST was found to be 65 and 66% respectively. However, combined usage of QFT-GIT and TST was found to be more sensitive (85%) than TST or QFT-GIT alone (P < 0.0001). Although negative results of QFT-GIT or TST did not exclude the diagnosis of active TB in children, their positivity supported the diagnosis. Specificity could not be measured as only microbiologically confirmed cases of Mycobacterium tuberculosis disease were enrolled in the study.

CONCLUSION

Although sensitivities of TST and QFT-GIT are too low to exclude active TB, their positivity supports diagnosis of active TB in children concomitant with signs and symptoms. QFT-GIT and TST should be used together to enhance diagnostic sensitivity and could help exclude a diagnosis of TB if the pretest probability is low.

The seroconversion rate of QuantiFERON-TB Gold In-Tube test in psoriatic patients receiving secukinumab and ixekizumab, the anti-interleukin-17A monoclonal antibodies

BACKGROUND

For psoriatic patients receiving biologics, the concern of tuberculosis (TB) infection exists. Although the TB risk of anti-interleukin (IL)-17A agents is generally considered very low, more real-world data are needed to support the safety.

OBJECTIVES

This study aims to provide the real-world experience of using serial QuantiFERON-TB Gold In-Tube (QFT-GIT) test among patients treated with secukinumab or ixekizumab in Taiwan, an intermediate TB burden country, for the detection of latent TB infection (LTBI) reactivation or newly acquired TB infection.

METHODS

This retrospective review evaluated 100 consecutive patients with psoriasis receiving anti-IL-17A therapies who were checked with at least twice QFT-GIT between 2016 and 2019 in National Taiwan University Hospital, Taipei and Hsin-Chu, Taiwan.

RESULTS

Among the 100 patients, the baseline QFT-GIT results were negative in 81.0% (81/100), positive in 18.0% (18/100), and indeterminate in 1.0% (1/100) of patients. The overall outcomes in patients receiving at least 6 months of cumulative exposure to anti-IL-17A agents were persistently seronegative in 80 patients (80.0%), persistently seropositive in 14 patients (14.0%), seroconversion in 1 patient (1.0%), seroreversion in 3 patients (3.0%), and others in 2 patients (2.0%). In patients with at least 11 months of cumulative exposure, the seroconversion rate was 1.3% (1/79). The only case with seroconversion had a positive QFT-GIT result previously. No case of TB reactivation or newly acquired TB infection was identified during the follow-up.

CONCLUSIONS

In patients treated with anti-IL-17A monoclonal antibodies for psoriasis, routine serial repeat QFT-GIT testing was associated with lower seroconversion rate compared to real-world data of tumor necrosis factor-α inhibitors and anti-IL-12/23 antibody in Taiwan and in pivotal studies. Because clinical TB symptoms and signs are often preceded by QFT-GIF seroconversion, this result further supports the safety of anti-IL-17A agents in patients with psoriasis for LTBI.

DNA origami-based aptasensors

Traditional analytical techniques face many limitations such as time-consuming process, complicated sample preparation, high consumption of reagents and need for expensive equipment. So, it is important that simple, rapid and sensitive detection methods are introduced. Nucleic acids-based assays, particularly aptamers, have a great impact on modern life sciences for biological analysis and target detection. Aptamer-based biosensors with unique recognition properties including high specificity and affinity, rapid response and simple fabrication have attracted much attention. It is believed that two- and three-dimensional structures, sometimes referred to as DNA origami, using DNA aptamers can show more selective binding affinity and better stability over other nucleic acids forms. In this review, we will focus on recent advances in the development and uses of electrochemical and optical DNA origami-based aptasensors to supply readers with a comprehensive understanding of their improvements. Also, the challenges and awards of these approaches are discussed.

Prevention of tuberculosis in household members: estimates of children eligible for treatment

Objective

To estimate of the number of children younger than 5 years who were household contacts of people with tuberculosis and were eligible for tuberculosis preventive treatment in 2017.

Methods

To estimate the number of eligible children, we obtained national values for the number of notified cases of bacteriologically confirmed pulmonary tuberculosis in 2017, the proportion of the population younger than 5 years in 2017 and average household size from published sources. We obtained global values for the number of active tuberculosis cases per household with an index case and for the prevalence of latent tuberculosis infection among children younger than 5 years who were household contacts of a tuberculosis case through systematic reviews, meta-analysis and Poisson regression models.

Findings

The estimated number of children younger than 5 years eligible for tuberculosis preventive treatment in 2017 globally was 1.27 million (95% uncertainty interval, UI: 1.24–1.31), which corresponded to an estimated global coverage of preventive treatment in children of 23% at best. By country, the estimated number ranged from less than one in the Bahamas, Iceland, Luxembourg and Malta to 350 000 (95% UI: 320 000–380 000) in India. Regionally, the highest estimates were for the World Health Organization (WHO) South-East Asia Region (510 000; 95% UI: 450 000–580 000) and the WHO African Region (470 000; 95% UI: 440 000–490 000).

Conclusion

Tuberculosis preventive treatment in children was underutilized globally in 2017. Treatment should be scaled up to help eliminate the pool of tuberculosis infection and achieve the End TB Strategy targets.

Two interferon gamma release assays for predicting active tuberculosis: the UK PREDICT TB prognostic test study

BACKGROUND

Despite a recent decline in the annual incidence of tuberculosis (TB) in the UK, rates remain higher than in most Western European countries. The detection and treatment of latent TB infection (LTBI) is an essential component of the UK TB control programme.

OBJECTIVES

To assess the prognostic value and cost-effectiveness of the current two interferon gamma release assays (IGRAs) compared with the standard tuberculin skin test (TST) for predicting active TB among untreated individuals at increased risk of TB: (1) contacts of active TB cases and (2) new entrants to the UK from high-TB-burden countries.

DESIGN

A prospective cohort study and economic analysis.

PARTICIPANTS AND SETTING

Participants were recruited in TB clinics, general practices and community settings. Contacts of active TB cases and migrants who were born in high-TB-burden countries arriving in the UK were eligible to take part if they were aged ≥ 16 years.

MAIN OUTCOME MEASURES

Outcomes include incidence rate ratios comparing the incidence of active TB in those participants with a positive test result and those with a negative test result for each assay, and combination of tests and the cost per quality-adjusted life-year (QALY) for each screening strategy.

RESULTS

A total of 10,045 participants were recruited between May 2010 and July 2015. Among 9610 evaluable participants, 97 (1.0%) developed active TB. For the primary analysis, all test data were available for 6380 participants, with 77 participants developing active TB. A positive result for TST^a (positive if induration is ≥ 5 mm) was a significantly poorer predictor of progression to active TB than a positive result for any of the other tests. Compared with TST^b [positive if induration is ≥ 6 mm without prior bacillus Calmette-Guérin (BCG) alone, T-SPOT^®.TB (Oxford Immunotec Ltd, Oxford, UK), TST^a + T-SPOT.TB, TST^a + IGRA and the three combination strategies including TST^b were significantly superior predictors of progression. Compared with the T-SPOT.TB test alone, TST^a + T-SPOT.TB, TST^b + QuantiFERON^® TB Gold In-Tube (QFT-GIT; QIAGEN GmbH, Hilden, Germany) and TST^b + IGRA were significantly superior predictors of progression and, compared with QFT-GIT alone, T-SPOT.TB, TST^a + T-SPOT.TB, TST^a + QFT-GIT, TST^a + IGRA, TST^b + T-SPOT.TB, TST^b + QFT-GIT and TST^b + IGRA were significantly superior predictors of progression. When evaluating the negative predictive performance of tests and strategies, negative results for TST^a + QFT-GIT were significantly poorer predictors of non-progression than negative results for TST^a, T-SPOT.TB and TST^a + IGRA. The most cost-effective LTBI testing strategies are the dual-testing strategies. The cost and QALY differences between the LTBI testing strategies were small; in particular, QFT-GIT, TST^b + T-SPOT.TB and TST^b + QFT-GIT had very similar incremental net benefit estimates.

CONCLUSION

This study found modest differences between tests, or combinations of tests, in identifying individuals who would go on to develop active TB. However, a two-step approach that combined TST^b with an IGRA was the most cost-effective testing option.

IMPLICATIONS FOR PRACTICE AND FUTURE RESEARCH

The two-step TST^b strategy, which stratified the TST by prior BCG vaccination followed by an IGRA, was the most cost-effective approach. The limited ability of current tests to predict who will progress limits the clinical utility of tests. The implications of these results for the NHS England/Public Health England national TB screening programme for migrants should be investigated.

STUDY REGISTRATION

This study is registered as NCT01162265.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Accurate diagnosis of latent tuberculosis in children, people who are immunocompromised or at risk from immunosuppression and recent arrivals from countries with a high incidence of tuberculosis: systematic review and economic evaluation

BACKGROUND

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB) [(Zopf 1883) Lehmann and Neumann 1896], is a major cause of morbidity and mortality. Nearly one-third of the world's population is infected with MTB; TB has an annual incidence of 9 million new cases and each year causes 2 million deaths worldwide.

OBJECTIVES

To investigate the clinical effectiveness and cost-effectiveness of screening tests [interferon-gamma release assays (IGRAs) and tuberculin skin tests (TSTs)] in latent tuberculosis infection (LTBI) diagnosis to support National Institute for Health and Care Excellence (NICE) guideline development for three population groups: children, immunocompromised people and those who have recently arrived in the UK from high-incidence countries. All of these groups are at higher risk of progression from LTBI to active TB.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, The Cochrane Library and Current Controlled Trials were searched from December 2009 up to December 2014.

REVIEW METHODS

English-language studies evaluating the comparative effectiveness of commercially available tests used for identifying LTBI in children, immunocompromised people and recent arrivals to the UK were eligible. Interventions were IGRAs [QuantiFERON(®)-TB Gold (QFT-G), QuantiFERON(®)-TB Gold-In-Tube (QFT-GIT) (Cellestis/Qiagen, Carnegie, VA, Australia) and T-SPOT.TB (Oxford Immunotec, Abingdon, UK)]. The comparator was TST 5 mm or 10 mm alone or with an IGRA. Two independent reviewers screened all identified records and undertook a quality assessment and data synthesis. A de novo model, structured in two stages, was developed to compare the cost-effectiveness of diagnostic strategies.

RESULTS

In total, 6687 records were screened, of which 53 unique studies were included (a further 37 studies were identified from a previous NICE guideline). The majority of the included studies compared the strength of association for the QFT-GIT/G IGRA with the TST (5 mm or 10 mm) in relation to the incidence of active TB or previous TB exposure. Ten studies reported evidence on decision-analytic models to determine the cost-effectiveness of IGRAs compared with the TST for LTBI diagnosis. In children, TST (≥ 5 mm) negative followed by QFT-GIT was the most cost-effective strategy, with an incremental cost-effectiveness ratio (ICER) of £18,900 per quality-adjusted life-year (QALY) gained. In immunocompromised people, QFT-GIT negative followed by the TST (≥ 5 mm) was the most cost-effective strategy, with an ICER of approximately £18,700 per QALY gained. In those recently arrived from high TB incidence countries, the TST (≥ 5 mm) alone was less costly and more effective than TST (≥ 5 mm) positive followed by QFT-GIT or T-SPOT.TB or QFT-GIT alone.

LIMITATIONS

The limitations and scarcity of the evidence, variation in the exposure-based definitions of LTBI and heterogeneity in IGRA performance relative to TST limit the applicability of the review findings.

CONCLUSIONS

Given the current evidence, TST (≥ 5 mm) negative followed by QFT-GIT for children, QFT-GIT negative followed by TST (≥ 5 mm) for the immunocompromised population and TST (≥ 5 mm) for recent arrivals were the most cost-effective strategies for diagnosing LTBI that progresses to active TB. These results should be interpreted with caution given the limitations identified. The evidence available is limited and more high-quality research in this area is needed including studies on the inconsistent performance of tests in high-compared with low-incidence TB settings; the prospective assessment of progression to active TB for those at high risk; the relative benefits of two-compared with one-step testing with different tests; and improved classification of people at high and low risk for LTBI.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014009033.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Asian Organization for Crohn's and Colitis and Asia Pacific Association of Gastroenterology consensus on tuberculosis infection in patients with inflammatory bowel disease receiving anti-tumor necrosis factor treatment. Part 1: risk assessment

Because anti-tumor necrosis factor (anti-TNF) therapy has become increasingly popular in many Asian countries, the risk of developing active tuberculosis (TB) among anti-TNF users may raise serious health problems in this region. Thus, the Asian Organization for Crohn's and Colitis and the Asia Pacific Association of Gastroenterology have developed a set of consensus statements about risk assessment, detection and prevention of latent TB infection, and management of active TB infection in patients with inflammatory bowel disease (IBD) receiving anti-TNF treatment. Twenty-three consensus statements were initially drafted and then discussed by the committee members. The quality of evidence and the strength of recommendations were assessed by using the Grading of Recommendations Assessment, Development, and Evaluation methodology. Web-based consensus voting was performed by 211 IBD specialists from 9 Asian countries concerning each statement. A consensus statement was accepted if at least 75% of the participants agreed. Part 1 of the statements comprised 2 parts: risk of TB infection Recommendaduring anti-TNF therapy, and screening for TB infection prior to commencing anti-TNF therapy. These consensus statements will help clinicians optimize patient outcomes by reducing the morbidity and mortality related to TB infections in patients with IBD receiving anti-TNF treatment.

Asian Organization for Crohn's and Colitis and Asian Pacific Association of Gastroenterology consensus on tuberculosis infection in patients with inflammatory bowel disease receiving anti-tumor necrosis factor treatment. Part 1: Risk assessment

Because anti-tumor necrosis factor (anti-TNF) therapy has become increasingly popular in many Asian countries, the risk of developing active tuberculosis (TB) among anti-TNF users may raise serious health problems in this region. Thus, the Asian Organization for Crohn's and Colitis and the Asian Pacific Association of Gastroenterology have developed a set of consensus statements about risk assessment, detection, and prevention of latent TB infection and management of active TB infection in patients with inflammatory bowel disease (IBD) receiving anti-TNF treatment. Twenty-three consensus statements were initially drafted and then discussed by the committee members. The quality of evidence and the strength of recommendations were assessed by using the Grading of Recommendations Assessment, Development, and Evaluation methodology. Web-based consensus voting was performed by 211 IBD specialists from nine Asian countries concerning each statement. A consensus statement was accepted if at least 75% of the participants agreed. Part 1 of the statements comprised two parts: (i) risk of TB infection during anti-TNF therapy and (ii) screening for TB infection prior to commencing anti-TNF therapy. These consensus statements will help clinicians optimize patient outcomes by reducing the morbidity and mortality related to TB infections in patients with IBD receiving anti-TNF treatment.

Household tuberculosis contact investigation in a tuberculosis-prevalent country: Are the tuberculin skin test and interferon-gamma release assay enough in elderly contacts?

The high background rates of positive results on the tuberculin skin test (TST) and interferon-gamma release assay (IGRA) sometimes confuse the investigation of tuberculosis (TB) contact in TB-prevalent countries, particularly in elderly contacts. The aim was to investigate the predictive value of TST and IGRA for diagnosing latent TB infection (LTBI) in elderly household contacts in South Korea.In this retrospective study, TST and IGRA results of household contacts of suspected pulmonary TB patients were reviewed according to the index patient's final diagnosis (TB group: culture-confirmed pulmonary TB, non-TB group: pulmonary disease other than TB).A total of 249 contacts were included in the analysis (188 in the TB group and 61 in the non-TB group). In the TB group, TST and IGRA were positive in 42.6% and 45.7% of contacts, respectively. In the non-TB group, TST and IGRA were positive in 32.8% and 23.0% of contacts, respectively. TST did not show any differences between the TB and non-TB groups for any age group, whereas IGRA showed differences between the 2 groups for those ages 18 to 39 and 40 to 59 years. However, there were no significant differences between the groups for the ≥60 years old group.In elderly contacts, neither TST nor IGRA showed clear discrimination of positivity between the groups. Further studies are needed to predict which elderly contacts are at risk for progression to active TB as well as to accurately detect recent Mycobacterium tuberculosis infection in this vulnerable population.

Comparison of Interferon-γ Release Assays and the Tuberculin Skin Test for Diagnosis of Tuberculosis in Human Immunodeficiency Virus: A Systematic Review

Background

It remains uncertain if interferon-γ release assays (IGRAs) are superior to the tuberculin skin test (TST) for the diagnosis of active tuberculosis (TB) or latent tuberculosis infection (LTBI) in immunosuppressed populations including people with human immunodeficiency virus (HIV) infection. The purpose of this study was to systematically review the performance of IGRAs and the TST in people with HIV with active TB or LTBI in low and high prevalence TB countries.

Methods

We searched the MEDLINE database from 1966 through to January 2017 for studies that compared results of the TST with either the commercial QuantiFERON-TB Gold in Tube (QFTGT) assay or previous assay versions, the T-SPOT.TB assay or in-house IGRAs. Data were summarized by TB prevalence. Tests for concordance and differences in proportions were undertaken as appropriate. The variation in study methodology was appraised.

Results

Thirty-two studies including 4,856 HIV subjects met the search criteria. Fourteen studies compared the tests in subjects with LTBI in low TB prevalence settings. The QFTGT had a similar rate of reactivity to the TST, although the first-generation version of that assay was reactive more commonly. IGRAs were more frequently positive than the TST in HIV infected subjects with active TB. There was considerable study methodology and population heterogeneity, and generally low concordance between tests. Both the TST and IGRAs were affected by CD4 T-cell immunodeficiency.

Conclusion

Our review of comparative data does not provide robust evidence to support the assertion that the IGRAs are superior to the TST when used in HIV infected subjects to diagnose either active TB or LTBI.

Interferon-gamma release assay for the diagnosis of latent tuberculosis infection: A latent-class analysis

BACKGROUND

Accurate diagnosis and subsequent treatment of latent tuberculosis infection (LTBI) is essential for TB elimination. However, the absence of a gold standard test for diagnosing LTBI makes assessment of the true prevalence of LTBI and the accuracy of diagnostic tests challenging. Bayesian latent class models can be used to make inferences about disease prevalence and the sensitivity and specificity of diagnostic tests using data on the concordance between tests. We performed the largest meta-analysis to date aiming to evaluate the performance of tuberculin skin test (TST) and interferon-gamma release assays (IGRAs) for LTBI diagnosis in various patient populations using Bayesian latent class modelling.

METHODS

Systematic search of PubMeb, Embase and African Index Medicus was conducted without date and language restrictions on September 11, 2017 to identify studies that compared the performance of TST and IGRAs for LTBI diagnosis. Two IGRA methods were considered: QuantiFERON-TB Gold In Tube (QFT-GIT) and T-SPOT.TB. Studies were included if they reported 2x2 agreement data between TST and QFT-GIT or T-SPOT.TB. A Bayesian latent class model was developed to estimate the sensitivity and specificity of TST and IGRAs in various populations, including immune-competent adults, immune-compromised adults and children. A TST cut-off value of 10 mm was used for immune-competent subjects and 5 mm for immune-compromised individuals.

FINDINGS

A total of 157 studies were included in the analysis. In immune-competent adults, the sensitivity of TST and QFT-GIT were estimated to be 84% (95% credible interval [CrI] 82-85%) and 52% (50-53%), respectively. The specificity of QFT-GIT was 97% (96-97%) in non-BCG-vaccinated and 93% (92-94%) in BCG-vaccinated immune-competent adults. The estimated figures for TST were 100% (99-100%) and 79% (76-82%), respectively. T-SPOT.TB has comparable specificity (97% for both tests) and better sensitivity (68% versus 52%) than QFT-GIT in immune-competent adults. In immune-compromised adults, both TST and QFT-GIT display low sensitivity but high specificity. QFT-GIT and TST are equally specific (98% for both tests) in non-BCG-vaccinated children; however, QFT-GIT is more specific than TST (98% versus 82%) in BCG-vaccinated group. TST is more sensitive than QFT-GIT (82% versus 73%) in children.

CONCLUSIONS

This study is the first to assess the utility of TST and IGRAs for LTBI diagnosis in different population groups using all available data with Bayesian latent class modelling. Our results challenge the current beliefs about the performance of LTBI screening tests, and have important implications for LTBI screening policy and practice. We estimated that the performance of IGRAs is not as reliable as previously measured in the general population. However, IGRAs are not or minimally affected by BCG and should be the preferred tests in this setting. Adoption of IGRAs in settings where BCG is widely administered will allow for a more accurate identification and treatment of LTBI.

Comparison of the Performance of Urinary Mycobacterium tuberculosis Antigens Cocktail (ESAT6, CFP10, and MPT64) with Culture and Microscopy in Pulmonary Tuberculosis Patients

Pulmonary tuberculosis (TB) is a major global health problem and is one of the top 10 causes of death worldwide. Our study aimed to evaluate the performance of urinary Mycobacterium tuberculosis (Mtb) antigens cocktail (ESAT6, CFP10, and MPT64) compared with culture and microscopy. This descriptive cross-sectional study was conducted in Dr. Hasan Sadikin General Hospital, Bandung, from January 2014 to October 2016. A total of 141 pulmonary tuberculosis patients were included. Sputum samples were examined for acid-fast bacilli (ZN stain) and mycobacterial culture (LJ); the Mtb antigens cocktail was examined in the urine sample. The positivity rate of TB detection from the three methods was as follows: AFB 52/141 (36.9%), culture 50/141 (35.5%), and urinary Mtb antigens cocktail 95/141 (67.4%). Sensitivity, specificity, PPV, and NPV of urinary Mtb antigens cocktail were 68.2%, 33%, 31.6%, and 69.6%, respectively. Validity of combination of both methods with culture as a gold standard yielded sensitivity, specificity, PPV, and NPV of 90%, 28.6%, 40.9%, and 83.8%, respectively. Combination of urinary Mtb antigens cocktail with AFB as a screening test gives a good sensitivity, although the specificity is reduced. Urinary Mtb antigens cocktail can be used as screening test for pulmonary tuberculosis.

Serial QuantiFERON-TB Gold testing in patients with psoriasis treated with ustekinumab

BACKGROUND

There is increasing concern about the risk of latent tuberculosis infection (LTBI) reactivation during the use of biologics for psoriasis. Although ustekinumab had been documented with low risk of tuberculosis, the long-term follow-up of LTBI as determined by QuantiFERON-TB Gold (QFT-G) testing in patients treated with ustekinumab is limited.

OBJECTIVES

This study aims to use serial QFT-G testing as a screening method for detecting LTBI in patients with psoriasis from an intermediate tuberculosis burden country.

METHODS

This retrospective review investigated 134 psoriatic patients in whom ustekinumab was prescribed for at least one year between 2010 and 2016 in National Taiwan University Hospital. All patients underwent annular QFT-G testing during ustekinumab therapy.

RESULTS

Among the 134 enrolled patients, baseline LTBI rate was 13.4% (18/134). Indeterminate QFT-G result was noted in 5.2% (7/134) of patients and 71.4% (5/7) of them turn to be QFT-G negative during the next testing. 81.3% (109/134) of patients had a negative QFT-G at baseline and the seroconversion rate was 7.3% (8/109) in the serial QFT-G. All the patients in the conversion group were referred to a pulmonologist for evaluation and 81.5% (22/27) of them underwent chemoprophylactic therapy while on ustekinumab. No active TB infection was noted during further follow-up with or without chemoprophylaxis.

CONCLUSIONS

This study revealed that psoriatic patients receiving long-term ustekinumab therapy had a low QFT-G conversion rate (7.3%). The clinical significance of QFT-G conversion remains controversial and needs larger scale trials to investigate.

Striking the right immunological balance prevents progression of tuberculosis

INTRODUCTION

Tuberculosis (TB) caused by infection with Mycobacterium tuberculosis (Mtb) is a major burden for human health worldwide. Current standard treatments for TB require prolonged administration of antimycobacterial drugs leading to exaggerated inflammation and tissue damage. This can result in the reactivation of latent TB culminating in TB progression. Thus, there is an unmet need to develop therapies that would shorten the duration of anti-TB treatment and to induce optimal protective immune responses to control the spread of mycobacterial infection with minimal lung pathology.

FINDINGS

Granulomata is the hallmark structure formed by the organized accumulation of immune cells including macrophages, natural killer cells, dendritic cells, neutrophils, T cells, and B cells to the site of Mtb infection. It safeguards the host by containing Mtb in latent form. However, granulomata can undergo caseation and contribute to the reactivation of latent TB, if the immune responses developed to fight mycobacterial infection are not properly controlled. Thus, an optimal balance between innate and adaptive immune cells might play a vital role in containing mycobacteria in latent form for prolonged periods and prevent the spread of Mtb infection from one individual to another.

CONCLUSION

Optimal and well-regulated immune responses against Mycobacterium tuberculosis may help to prevent the reactivation of latent TB. Moreover, therapies targeting balanced immune responses could help to improve treatment outcomes among latently infected TB patients and thereby limit the dissemination of mycobacterial infection.

Diagnosis of Latent Tuberculosis Infection

For 2015, tuberculosis (TB) incidence in the United States has plateaued at 3.0 per 100,000. This remains the lowest case rate since recording started. On the global level, although the TB epidemic is larger than previously estimated, TB deaths and incidence rate continue to fall. For both low and high incidence countries, accelerating the decline in TB incidence towards elimination goals requires that more emphasis be placed on strengthening systems for detection and treatment of latent TB infection (LTBI) in addition to improving TB care globally. Here, we review the tuberculin skin test and gamma interferon release assays currently available for the detection of LTBI.

Tuberculosis Associated with HIV Infection

Tuberculosis (TB) has recently surpassed HIV as the primary infectious disease killer worldwide, but the two diseases continue to display lethal synergy. The burden of TB is disproportionately borne by people living with HIV, particularly where HIV and poverty coexist. The impact of these diseases on one another is bidirectional, with HIV increasing risk of TB infection and disease progression and TB slowing CD4 recovery and increasing progression to AIDS and death among the HIV infected. Both antiretroviral therapy (ART) and latent TB infection (LTBI) treatment mitigate the impact of coinfection, and ART is now recommended for HIV-infected patients independent of CD4 count. LTBI screening should be performed for all HIV-positive people at the time of diagnosis, when their CD4 count rises above 200, and yearly if there is repeated exposure. Tuberculin skin tests (TSTs) may perform better with serial testing than interferon gamma release assays (IGRAs). Any patient with HIV and a TST induration of ≥5 mm should be evaluated for active TB disease and treated for LTBI if active disease is ruled out. Because HIV impairs multiple aspects of immune function, progressive HIV is associated with lower rates of cavitary pulmonary TB and higher rates of disseminated and extrapulmonary disease, so a high index of suspicion is important, and sputum should be obtained for evaluation even if chest radiographs are negative. TB diagnosis is similar in patients with and without TB, relying on smear, culture, and nucleic acid amplification tests, which are the initial tests of choice. TSTs and IGRAs should not be used in the evaluation of active TB disease since these tests are often negative with active disease. Though not always performed in resource-limited settings, drug susceptibility testing should be performed on all TB isolates from HIV-positive patients. Urine lipoarabinomannan testing may also be helpful in HIV-positive patients with disseminated disease. Treatment of TB in HIV-infected patients is similar to that of TB in HIV-negative patients except that daily therapy is required for all coinfected patients, vitamin B6 supplementation should be given to all coinfected patients receiving isoniazid to reduce peripheral neuropathy, and specific attention needs to be paid to drug-drug interactions between rifamycins and many classes of antiretrovirals. In patients requiring ART that contains ritonavir or cobicistat, this can be managed by the use of rifabutin at 150 mg daily in place of rifampin. For newly diagnosed coinfected patients, mortality is lower if treatment is provided in parallel, rather than serially, with treatment initiation within 2 weeks preferred for those with CD4 counts of <50 and within 8 to 12 weeks for those with higher CD4 counts. When TB immune reconstitution inflammatory syndrome occurs, patients can often be treated symptomatically with nonsteroidal anti-inflammatory drugs, but a minority will benefit from steroids. Generally, patients who do not have space-occupying lesions such as occurs in TB meningitis do not require cessation of therapy.

Tuberculous meningoencephalitis associated with brain tuberculomas during pregnancy: a case report

Background

Tuberculous meningitis is globally highly prevalent and is commoner in resource-limited countries and in patients with immunosuppression. Central nervous system tuberculosis is one of the severest forms of extrapulmonary tuberculosis during pregnancy and associated brain tuberculomas have been rarely reported. With the availability of neuroimaging at our hospital center, we present the first case of tuberculous meningoencephalitis associated with brain tuberculomas during pregnancy.

Case presentation

In this case report we present a 25-year-old, Albanian, pregnant woman living in an urban area in Kosovo, who at 24 weeks of twin pregnancy manifested signs and symptoms of meningoencephalitis with decreased level of consciousness, hemiparesis, and generalized recurrent seizures. Based on medical history, origin from a region of high prevalence of tuberculosis, clinical presentation, especially neurological examination, cytobiochemical changes in cerebrospinal fluid (mild mononuclear pleocytosis with decreased level of glucose and elevated proteins), and elevated level of interferon-gamma release assay in cerebrospinal fluid, antituberculous therapy was initiated on the fourth day of admission. After 3 weeks of treatment, at 27 weeks of pregnancy, she had a preterm delivery and both twins, with low birthweight, died after 24 and 72 hours. Although findings on chest radiography were normal, brain magnetic resonance imaging showed signs of meningoencephalitis and multiple intracerebral tuberculomas, while Koch’s bacillus was isolated from urine cultures. On long-term follow-up after delivery, she was cured with no sequelae and became pregnant again without any additional complications.

Conclusions

In countries with a high prevalence of tuberculosis, screening for central nervous system tuberculosis should be considered in the differential diagnosis of meningitis in pregnancy. Cerebral imaging is essential to establish the diagnosis of brain tuberculomas in such a case of suspected tuberculous meningoencephalitis during pregnancy.

Comparing tuberculin skin test and interferon γ release assay (T-SPOT.TB) to diagnose latent tuberculosis infection in household contacts

BACKGROUND/AIMS

The tuberculin skin test (TST) and interferon γ release assay are currently used as diagnostic tools to detect latent tuberculosis (TB) infection; however, there are inconsistencies about the degree of agreement between the tests. We aimed to evaluate the concordance rate between the two tests in household contacts of a country with intermediate TB burden, where most people were vaccinated.

METHODS

We recruited household contacts who spent > 8 hours daily with patients with microbiologically confirmed active pulmonary TB, and received both TST and T-SPOT.TB (Oxford Immunotec) simultaneously. The degree of agreement was analysed according to TST cutoff and Bacille Calmette-Guerin (BCG) vaccination status. Relevant factors were analysed to establish the association with TST or T-SPOT.TB.

RESULTS

Among 298 household contacts, 122 (40.9%) were spouses, and 250 (83.9%) had received BCG vaccination. In the contact sources, 117 (39.3%) showed a positive result for acid-fast bacillus (AFB) sputum smear and 109 (36.6%) had cavities. The highest agreement rate of 69.5% and κ value of 0.378 were found with a 10 mm cutoff. Spouse, time interval from TB diagnosis to test, and AFB sputum smear positivity were significantly associated with a positive result for T-SPOT.TB. Sex, BCG vaccination, and cavity on chest computed tomography were related to TST positivity.

CONCLUSIONS

The present study suggested it was not possible for TST and T-SPOT.TB to replace each other because of considerable discrepancy between the two tests in household contacts in a country with intermediate TB prevalence.

Comparison of QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) for diagnosis of latent tuberculosis in haemodialysis (HD) patients: a meta-analysis of κ estimates

Diagnosis of latent tuberculosis infection (LTBI) is a concern in haemodialysis (HD) patients. Many studies have compared QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) for detecting LTBI and reported the κ statistic of agreement between QFT-GIT and TST in HD patients. The present study aimed to systematically review this literature and conduct meta-analysis of individual studies that estimated the κ between QFT-GIT with TST among HD patients. All relevant published studies that were available as full-text were obtained by searching Medline (1950), Web of Sciences (1945), Scopus (1973) through May 2016. The κ was re-estimated from the individual studies and pooled using random effect meta-analysis. Subgroup analysis and meta-regression were applied to evaluate the effect of Bacillus Calmette-Guérin (BCG) vaccination, TST cut-off points, quality of studies, sample size and age on variation of κ estimate. Eight studies involving 901 HD patients were included in meta-analysis. The pooled κ estimate was 0·28 (I 2 = 18·4%, P = 0·239, 95% confidence intervals 0·22-0·34). The discordance of TST-/QFT-GIT+ was more than TST+/QFT-GIT-. History of BCG vaccination, TST cut-off points and age are related to variation of κ estimates. TST and QFT-GIT are not comparable in detecting LTBI in HD patients. The higher TST-/QFT-GIT+ ratio compared with TST+/QFT-GIT- ratio, may indicate the superiority of QFT-GIT over TST for detection LTBI in HD patients.

Inflammatory markers and clinical characteristics for predicting persistent positivity of interferon gamma release assay in dialysis population

The interferon-gamma release assay (IGRA) is useful for diagnosing latent tuberculosis infection (LTBI), however the rate of negative conversion is high, especially in dialysis patients. Few studies have focused on predicting persistently positive patients who are at high risk of tuberculosis reactivation. We screened dialysis patients, and used QuantiFERON-TB Gold In-tube (QFT-GIT) to identify LTBI. Of the 157 participants who had initially positive QFT-GIT, 82 had persistently positivity and 75 had negative conversion. The persistently positive group were younger, more were current smokers, and had higher plasma level of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and QFT-GIT responses than the negative conversion group. Multivariate logistic regression for persistent positivity revealed that high plasma sTREM-1 and QFT-GIT response, young age and TB contact history were independent factors. Currently smoking had borderline significance. The area under the receiver operating characteristic curve using the multi-factor model was 0.878, higher than 0.821 by QFT-GIT response of 0.95 IU/ml. In conclusion, dialysis patients with persistent LTBI status may be associated with a young age, high plasma sTREM-1, strong QFT-GIT response, currently smoking, and TB contact history. If resources are limited, these five predictors can be used to prioritize QFT-GIT-positive dialysis patients for LTBI treatment.

Interferon-Gamma Release Assays and Pediatric Public Health Tuberculosis Screening: The San Francisco Program Experience 2005 to 2008

BACKGROUND

Interferon-gamma release assay utilization in pediatric tuberculosis (TB) screening is limited by a paucity of longitudinal experience, particularly in low-TB burden populations.

METHODS

We conducted a retrospective review of QuantiFERON (QFT)-TB Gold results in San Francisco children from 2005 to 2008. Concordance with the tuberculin skin test (TST) was analyzed for a subset of children. Progression to active disease was determined through San Francisco and California TB registry matches.

RESULTS

Of 1092 children <15 years of age, 853 (78%) were foreign-born, and 136 (12%) were exposed to active TB cases (contacts). QuantiFERON tests were positive in 72 of 1092 (7%) children; 15 of 136 (11%) recent contacts; 53 of 807 (7%) foreign-born noncontacts; and 4 of 149 (3%) US-born noncontacts. QuantiFERON-negative/TST-positive discordance was seen more often in foreign-born/bacille Calmette-Guerin (BCG)-vaccinated children <5 years of age (52 of 56, 93%) compared to those ≥ 5 years of age (90 of 123, 73%; P = .003). Foreign-born, BCG-vaccinated children were more than twice as likely to have a discordant (79%) result as US-born, non-BCG-vaccinated children (37%; P < .0001). During 5587 person-years of follow-up of untreated children, including 146 TST-positive/QFT-negative children, no cases of active TB were identified, consistent with a negative predictive value of 100%.

CONCLUSIONS

Our experience supports the use of QFT to evaluate latent TB infection in children, particularly young BCG-vaccinated children. The proportion of QFT-positive results correlated with risk of exposure, and none of the untreated QFT-negative children developed TB. The low QFT-positive rate highlights the need for more selective testing based on current epidemiology and TB exposure risk.

Risk of Tuberculosis Among Patients on Dialysis: The Predictive Value of Serial Interferon-Gamma Release Assay

Patients on long-term dialysis are at high risk for tuberculosis (TB). Although latent tuberculosis infection (LTBI) is good target for TB eradication, interferon-gamma release assay-defined LTBI has a high proportion of negative conversion and lacks active TB correlation among patients on dialysis.Patients on long-term dialysis were screened in multiple centers in Taiwan. QuantiFERON-TB Gold In-tube (QFT-GIT) was used to define LTBI and was performed thrice at 6-month intervals. The primary outcome was active TB diagnosed after LTBI screening. The incidence and predictive value of QFT-GIT were analyzed.The 940 dialysis patients enrolled had an average age of 59.3 years. The initial QFT-GIT results were positive in 193, including 49.6% with persistent positive results on second check. In an average follow-up period of 3 years, 7 patients had TB. Three (319.1 per 100,000 person-yrs) and 4 (141.8 per 100,000 person-yrs) of them were prevalent and incident TB cases, respectively. Persistent positive QFT-GIT for 2 and 3 times correlated with increased hazard ratio for TB (14.44 and 20.29, respectively) compared with a single positive result (hazard ratio 10.38). Among those with 3 positive QFT-GIT results, TB development rate was 4.5% and incidence rate was 1352.3 per 100,000 person-years. In contrast, none of the incident TB occurred in those with initial positive and then negative conversion of QFT-GIT.In an area of intermediate TB incidence, dialysis patients have high TB risk. LTBI status is a good predictor of TB development, especially for those with more than 1 positive result. After excluding prevalent TB cases, serial follow-up of LTBI may narrow the target population to reduce treatment costs.

Interferon-gamma release assays and tuberculin skin testing for diagnosing latent Mycobacterium tuberculosis infection in at-risk groups in Poland

OBJECTIVE/BACKGROUND

The diagnostics of latent tuberculosis infection in Poland using the tuberculin skin test is challenging due to the obligatory Bacillus Calmette-Guérin vaccinations. Interferon-gamma release assays are still very rarely used for diagnostics. We compared the tuberculin skin test and the QuantiFERON-TB Gold In-Tube test to evaluate the degree of latent tuberculosis infection in at-risk groups for tuberculosis (homeless, close contacts, periodic contacts, nursing-home attendees) and in healthy individuals.

METHODS

QuantiFERON-TB Gold In-Tube tests were carried out on 785 individuals from the homeless (n=150), close contacts (n=171), periodic contacts (n=163), nursing-home attendees (n=152), and healthy individuals (n=149). The tuberculin skin test was performed on 129, 156, 147, 148, and 121 participants, respectively. We evaluated the (a) correlation between serum concentrations of interferon gamma and the tuberculin-skin-test induration diameter; (b) between the number of QuantiFERON-TB Gold In-Tube-positive results and the tuberculin-skin-test diameter in the studied groups; and (c) agreement between both tests and the kappa coefficient using the tuberculin-skin-test diameters of 5, 10, and 15mm.

RESULTS

Larger tuberculin-skin-test induration diameters were associated with elevated serum concentrations of interferon gamma. We found a positive correlation between the number of positive QuantiFERON-TB Gold In-Tube screening results and the tuberculin-skin-test induration diameter. The agreement between QuantiFERON-TB Gold In-Tube and tuberculin-skin-test screening results improved with increasing tuberculin-skin-test induration diameter.

CONCLUSION

Based on measures of tuberculin-skin-test induration diameter alone, it is difficult to diagnose latent tuberculosis infection with certainty. The agreement of the QuantiFERON-TB Gold In-Tube test increases with the tuberculin-skin-test diameter. Tuberculin-skin-test diameters larger than 15mm are more likely to be associated with active infection.

Predicting the Development of Tuberculosis with the Tuberculin Skin Test and QuantiFERON Testing

RATIONALE

The identification of patients with latent tuberculosis infection, who are at higher risk to develop active disease, is an important component of disease control.

OBJECTIVES

We aim to compare the usefulness of the QuantiFERON-TB Gold in-tube assay and the tuberculin skin test to predict the development of active tuberculosis during follow-up, using positive and negative predictive values, positive likelihood ratios, and stratified level of risk.

METHODS

The study included contacts of tuberculosis cases diagnosed between 2007 and 2009. All contacts included were from the first circle of exposure. Tuberculin skin test and QuantiFERON test were performed and a chest radiograph was obtained during the contact's study.

MEASUREMENTS AND MAIN RESULTS

A total of 1,335 contacts were followed up for 4 years: a smear-positive index case was identified for 937 contacts, of whom 15 developed active tuberculosis and had initially presented with positive tuberculin skin test/QuantiFERON results, a normal chest radiograph, and no symptoms. The positive predictive value was 4% for QuantiFERON and 2% for the tuberculin skin test (when ≥5 mm). The probability of developing active disease was 2.36 times higher with a positive QuantiFERON, and 1.3 times higher with a positive tuberculin skin test. The positive predictive value was 17%, and the positive likelihood ratio was 7.53 for untreated contacts with a positive QuantiFERON. Stratifying according to initial QuantiFERON results showed a 6.36 times higher risk of developing active tuberculosis for patients with a QuantiFERON result greater than or equal to 10 IU/ml. Among bacillus Calmette-Guérin-vaccinated patients, a tuberculin skin test induration greater than or equal to 15 mm correlated better with a positive QuantiFERON.

CONCLUSIONS

QuantiFERON results were more accurate than tuberculin skin test results in predicting tuberculosis. Although all contacts with QuantiFERON-positive results are at risk of developing tuberculosis, those with a tuberculin skin test induration greater than or equal to 15 mm and QuantiFERON greater than or equal to 10 IU/ml are at highest risk. This has important implications in the clinical management of tuberculosis contacts.

Comparison of latent tuberculosis infection rate between contacts with active tuberculosis and non-contacts

BACKGROUND

Latent tuberculosis infection (LTBI) rate is usually high in contacts with infectious TB patients. In TB-prevalent country, however, background LTBI rate is already high in general population.

AIM

To compare the LTBI rate between controls and recognized close contacts.

METHOD

Between February 2010 and January 2014, 183 controls and 376 contacts with TB infection were enrolled. The tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube (QFT-GIT) were used to diagnose LTBI.

RESULTS

Higher TST positivity was found in the control group than in the contact group (37.7% vs. 29.9%, P = 0.073). The positive QFT-GIT rate was higher in contacts than in controls (32.6% vs. 24.1%, P = 0.054). A significantly higher positive QFT-GIT rate was found in contacts under 30 years of age than in controls (16.1% vs. 0%, P = 0.005).

CONCLUSION

In a TB-prevalent country, both TST and QFT-GIT were limited in the diagnosis of recent LTBI in adult contacts probably due to the high background LTBI rate. However, QFT-GIT seems to be better than TST in differentiating LTBI status in contacts younger than 30 year old.

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Accuracy of QuantiFERON-TB Gold Test for Tuberculosis Diagnosis in Children

Objectives

To evaluate the accuracy of the QuantiFERON-TB Gold assay (QFT-IT) in children with suspected active or latent TB infection (LTBI).

Methods

A retrospective study was conducted on 621 children (0–14 years old) evaluated for TB infection or disease. Following clinical assessment, children were tested with the QFT-IT assay.

Results

Among the 140 active TB suspects, we identified 19 cases of active disease. The overall sensitivity for active TB was 87.5%, ranging from 62.5% in children 25–36 months old to 100% in children older than 49 months. The overall specificity for active TB was 93.6%. Among the 481 children tested for LTBI screening, 38 scored positive and all but 2 had at least one risk factor for TB infection. Among the 26 children with indeterminate results, bacterial, viral or fungal pneumonia were later diagnosed in 11 (42.3%) cases and non-TB related extra-pulmonary infections in 12 (46.1%).

Conclusions

Our results indicate that the children's response to QFT-IT associates to active TB and risk factors for LTBI. Moreover, we show that mitogen response is also found in children of 1 year of age, providing support for QFT-IT use also in young children.

Do the tuberculin skin test and the QuantiFERON-TB Gold in-tube test agree in detecting latent tuberculosis among high-risk contacts? A systematic review and meta-analysis

OBJECTIVES:

The QuantiFERON-TB Gold in-tube test (QFT-GIT) and the tuberculin skin test (TST) are used to diagnose latent tuberculosis infection (LTBI). However, conclusive evidence regarding the agreement of these two tests among high risk contacts is lacking. This systematic review and meta-analysis aimed to estimate the agreement between the TST and the QFT-GIT using kappa statistics.

METHODS:

According to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines, scientific databases including PubMed, Scopus, and Ovid were searched using a targeted search strategy to identify relevant studies published as of June 2015. Two researchers reviewed the eligibility of studies and extracted data from them. The pooled kappa estimate was determined using a random effect model. Subgroup analysis, Egger’s test and sensitivity analysis were also performed.

RESULTS:

A total of 6,744 articles were retrieved in the initial search, of which 24 studies had data suitable for meta-analysis. The pooled kappa coefficient and prevalence-adjusted bias-adjusted kappa were 0.40 (95% confidence interval [CI], 0.34 to 0.45) and 0.45 (95% CI, 0.38 to 0.49), respectively. The results of the subgroup analysis found that age group, quality of the study, location, and the TST cutoff point affected heterogeneity for the kappa estimate. No publication bias was found (Begg’s test, p=0.53; Egger’s test, p=0.32).

CONCLUSIONS:

The agreement between the QFT-GIT and the TST in diagnosing LTBI among high-risk contacts was found to range from fair to moderate.

Latent tuberculosis in kidney and liver transplant patients: a review of treatment practices and outcomes

BACKGROUND

The standard treatment of latent tuberculosis infection (LTBI) is associated with toxicities and data are limited on tolerability among patients with advanced organ disease listed for transplant. Alternate options are available, but they have yet to be studied in this population.

METHODS

A retrospective review of the treatment of LTBI among kidney and/or liver transplant candidates was conducted to assess factors impacting therapy initiation, tolerability, and completion of therapy.

RESULTS

Of 174 eligible patients, treatment of LTBI was initiated in 129, of which 91 were listed for kidney transplant and 38 were listed for liver or liver/kidney transplant. Infectious Diseases consultation was independently associated with treatment initiation when controlling for waitlisted organ and receipt of hemodialysis (odds ratio [OR] 81.14, 95% confidence interval [CI] 23.94-274.94, P < 0.001). Documented completion of first-line therapy was 47% overall, and 49% and 39%, respectively, among kidney and liver/kidney candidates (P = not significant). On multivariable analysis, controlling for baseline aspartate aminotransferase and waitlisted organ, first-line receipt of rifampin was associated with lower rates of treatment completion (OR 0.19, 95% CI 0.05-0.77, P = 0.02).

CONCLUSION

Based on medical record documentation, completion of first-line therapy was <50% in this cohort, although this is likely an underestimate, as 34% of patients had no chart documentation that therapy was completed. Approximately 20% of patients did not complete first-line therapy because of adverse effects.

A Clinical Algorithm to Identify HIV Patients at High Risk for Incident Active Tuberculosis: A Prospective 5-Year Cohort Study

Background

Predicting the risk of tuberculosis (TB) in people living with HIV (PLHIV) using a single test is currently not possible. We aimed to develop and validate a clinical algorithm, using baseline CD4 cell counts, HIV viral load (pVL), and interferon-gamma release assay (IGRA), to identify PLHIV who are at high risk for incident active TB in low-to-moderate TB burden settings where highly active antiretroviral therapy (HAART) is routinely provided.

Materials and Methods

A prospective, 5-year, cohort study of adult PLHIV was conducted from 2006 to 2012 in two hospitals in Taiwan. HAART was initiated based on contemporary guidelines (CD4 count < = 350/μL). Cox regression was used to identify the predictors of active TB and to construct the algorithm. The validation cohorts included 1455 HIV-infected individuals from previous published studies. Area under the receiver operating characteristic (ROC) curve was calculated.

Results

Seventeen of 772 participants developed active TB during a median follow-up period of 5.21 years. Baseline CD4 < 350/μL or pVL ≥ 100,000/mL was a predictor of active TB (adjusted HR 4.87, 95% CI 1.49–15.90, P = 0.009). A positive baseline IGRA predicted TB in patients with baseline CD4 ≥ 350/μL and pVL < 100,000/mL (adjusted HR 6.09, 95% CI 1.52–24.40, P = 0.01). Compared with an IGRA-alone strategy, the algorithm improved the sensitivity from 37.5% to 76.5%, the negative predictive value from 98.5% to 99.2%. Compared with an untargeted strategy, the algorithm spared 468 (60.6%) from unnecessary TB preventive treatment. Area under the ROC curve was 0.692 (95% CI: 0.587–0.798) for the study cohort and 0.792 (95% CI: 0.776–0.808) and 0.766 in the 2 validation cohorts.

Conclusions

A validated algorithm incorporating the baseline CD4 cell count, HIV viral load, and IGRA status can be used to guide targeted TB preventive treatment in PLHIV in low-to-moderate TB burden settings where HAART is routinely provided to all PLHIV. The implementation of this algorithm will avoid unnecessary exposure of low-risk patients to drug toxicity and simultaneously, reduce the burden of universal treatment on the healthcare system.

Biomarkers for risk of developing active tuberculosis in contacts of TB patients: a prospective cohort study

Identifying those Mycobacterium tuberculosis latent-infected individuals most at risk of developing active tuberculosis (TB) using routine clinical and laboratory tests remains a huge challenge in TB control efforts. We conducted a prospective longitudinal study of clinical and laboratory markers associated with the risk of developing active TB in contacts with latent M. tuberculosis infection.HIV-negative household contacts (n=296) of pulmonary TB patients underwent monitoring of clinical features, full blood cell counts, tuberculin skin text (TST) and chest radiography performed regularly during 18 months of follow-up. Paired statistical tests, a Kaplan-Meier analysis and Cox proportional hazard modelling were performed on variables between contacts progressing or not progressing to active TB.The appearance of TB disease symptoms in contacts was significantly associated with an elevated peripheral percentage of blood monocytes (adjusted hazard ratio (aHR) 6.25, 95% CI 1.63-23.95; p<0.01), a ≥14 mm TST response (aHR 5.72, 95% CI 1.22-26.80; p=0.03) and an increased monocyte:lymphocyte ratio (aHR 4.97, 95% CI 1.3-18.99; p=0.03). Among contacts having TST ≥14 mm, a strong association with risk of progression to TB was found with an elevated blood monocyte percentage (aHR 8.46, 95% CI 1.74-41.22; p<0.01).Elevated percentage of peripheral blood monocytes plus an elevated TST response are potential biomarkers for identifying contacts of TB patients at highest risk of developing active TB.

Comparison of the Prevalence of Latent Tuberculosis Infection among Non-Dialysis Patients with Severe Chronic Kidney Disease, Patients Receiving Dialysis, and the Dialysis-Unit Staff: A Cross-Sectional Study

Background

Patients with renal failure are vulnerable to tuberculosis, a common worldwide infectious disease. In the growing dialysis population, the risk for tuberculosis among the associated sub-groups is important but unclear. This study investigated latent tuberculosis infection (LTBI) in patients with severe chronic kidney disease (CKD) and among dialysis-unit staff caring for patients on dialysis.

Methods

From January 2012 to June 2013, patients undergoing dialysis, those with severe CKD (estimated glomerular filtration rate <30ml/min/1.73 m²), and the dialysis-unit staff (nursing staff and doctors in hemodialysis units) in several Taiwan hospitals were prospectively enrolled. Interferon-gamma release assay (IGRA) through QuantiFERON-TB Gold In-tube was used to determine LTBI. Predictors for LTBI were analyzed.

Results

Of the 599 participants enrolled, 106 (25%) in the dialysis group were IGRA positive. This was higher than the seven (11%) among severe CKD patients and 12 (11%) in the dialysis-unit staff. Independent predictors of LTBI in patient with renal dysfunction were old age (odds ratio [OR]: 1.03 [1.01–1.04] per year increment), prior TB lesion on chest radiograph (OR: 2.90 [1.45–5.83]), serum albumin (OR: 2.59 [1.63–4.11] per 1 g/dl increment), and need for dialysis (OR: 2.47, [1.02–5.95]). The QFT-GIT response was similar among the three groups. Malignancy (OR: 4.91 [1.84–13.10]) and low serum albumin level (OR: 0.22 [0.10–0.51], per 1 g/dl decrease) were associated with indeterminate IGRA results.

Conclusions

More patients on dialysis have LTBI compared to those with severe CKD and the dialysis-unit staff. Old age, prior radiographic TB lesion, high serum albumin, and need for dialysis are predictors of LTBI in patients with renal failure. Patients with severe CKD are a lower priority for LTBI screening. The hemodialysis environment is not a risk for LTBI and dialysis-unit staff may be treated as general healthcare workers.