Risk of Occupational Latent Tuberculosis Infection among Health Personnel Measured by Interferon-Gamma Release Assays in Low Incidence Countries-A Systematic Review and Meta-Analysis

Prevalence of latent tuberculosis infection (LTBI) in healthcare workers in Latin America and the Caribbean: systematic review and meta-analysis

Background

Tuberculosis remains a significant global health concern, and healthcare workers (HCWs) face a high risk of acquiring latent tuberculosis infection (LTBI) through occupational exposure. In the Latin American and Caribbean (LAC) region, where the burden of tuberculosis is substantial, understanding the prevalence of LTBI among HCWs is crucial for effective infection control measures. Therefore, we conducted a systematic review and meta-analysis to estimate the prevalence of LTBI among HCWs in LAC countries.

Methods

Our search included MEDLINE, Scopus, EMBASE, Web of Science, and Google Scholar databases, focusing on relevant English-language records. We looked for observational studies from inception until December 2023.

Results

Our analysis included 38 studies representing 15,236 HCWs and 6,728 LTBI cases. These studies spanned the period from 1994 to 2023 and were conducted in Brazil, Peru, Cuba, Colombia, Trinidad and Tobago, Mexico, and Chile. The mean prevalence of LTBI among HCWs was 35.32% (range 17.86-56.00%) for interferon-gamma release assay (IGRA) and 43.67% (range 6.68-70.29%) for tuberculin skin test (TST). The pooled prevalence of LTBI among HCWs was 34.5% (95% CI 25.4-44.1%) for IGRA and 43.0% (95% CI 35.5-50.7%) for TST. When considering both IGRA and TST tests, the overall prevalence of LTBI among HCWs was 40.98% (95% CI 34.77-47.33%). LTBI was associated with longer lengths of employment and exposure to patients, family members, or any person with TB. Additionally, older HCWs faced a higher risk of LTBI. Specific professional roles (such as nurses, nurse technicians, or physicians), smoking, and deficient TB infection control measures increased the likelihood of LTBI. However, information regarding gender and BCG vaccination status showed discordance among studies.

Conclusion

Our findings underscore a substantial burden of LTBI among HCWs in LAC countries. Implementing adequate infection control measures is essential to prevent and control transmission within healthcare settings.

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

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

[Tuberculosis Infection Control & Hygiene - Recommendations of the DZK]

Preventing the spread of the disease is an essential goal in the care and treatment of tuberculosis. In addition to early diagnosis and effective therapies, isolation of infectious patients and adequate hygiene measures are of particular importance for infection prevention. The present recommendations replace the previous recommendations "tuberculosis infection control" from 2012 and take into account the current national and international recommendations and as well as new scientific findings. After a description of the infection and the transmission pathways, the necessary prevention and hygiene measures in health care facilities are comprehensively presented. Since the last revision of the recommendations on infection prevention, international recommendations and the KRINKO recommendation on ending isolation have been changed. In accordance with this, under certain conditions in the case of sensitive tuberculosis, de-isolation in health care facilities can take place after 14 days without taking the sputum findings into account. The second part of the recommendations explains in detail the measures to be taken in special situations and areas, such as general practitioners, ambulance services and care facilities. Here, the recommendations on respiratory protection have been simplified; for staff, an FFP2 mask is now generally considered sufficient.

Right to Occupational Safety: Prevalence of Latent Tuberculosis Infection in Healthcare Workers. A 1-Year Retrospective Survey Carried out at Hospital of Lecce (Italy)

BACKGROUND

Prevention of latent tuberculosis infection (LTBI) in healthcare workers (HCWs) to ensure the "Right to Occupational Safety" is a special challenge globally, as HCWs have a higher risk of acquiring the infection in hospital settings because of frequent close exposure to patients suffering from tuberculosis (TB).

METHODS

Aretrospective study was performed with the aim of assessing the prevalence of LTBI related to demographical and occupational risk factors among HCWs employed in a large hospital in Italy. The study involved 1461 HCWs screened for LTBI by Mantoux tuberculin skin test (TST) and then confirmed with Interferon Gamma Release Assay (IGRA) test in case of positivity. Immunosuppressed and BGC-vaccinated workers were tested directly with IGRA.

RESULTS

LTBI was diagnosed in 4.1% of the HCWs and the prevalence resulted lower than other studies conducted in low TB incidence countries. The variables significantly linked with higher frequency of the infection were: age ≥40 years (OR = 3.14; 95% CI: 1.13-8.74; p < 0.05), length of service ≥15 years (OR = 4.11; 95% CI: 1.48-11.43; p < 0.05) and not being trained on TB prevention (OR = 3.46; 95% CI: 1.85-6.46; p < 0.05). Not trained HCWs presented a higher risk of LTBI also after adjustment for age and length of service, compared to trained HCWs.

CONCLUSIONS

screening of HCWs for LTBI should be always considered in routinely occupational surveillance in order to early diagnose the infection and prevent its progression. Safety policies in hospital settings centered on workers' training on TB prevention is crucial to minimize LTBI occurrence in HCWs.

Systematic review of latent tuberculosis infection research to inform programmatic management in Ireland

The World Health Organisation (WHO) End Tuberculosis (TB) Strategy and the WHO Framework Towards Tuberculosis Elimination in Low Incidence Countries state that latent tuberculosis infection (LTBI) screening and treatment in selected high-risk groups is a priority action to eliminate TB. The European Centre for Disease Prevention and Control (ECDC) advises that this should be done through high-quality programmatic management, which they describe as having six key components. The research aim was to systematically review the literature to identify what is known about the epidemiology of LTBI and the uptake and completion of LTBI screening and treatment in Ireland to inform the programmatic management of LTBI nationally. A systematic literature review was performed according to a review protocol and reported in adherence with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Twenty-eight studies were eligible for inclusion and described LTBI screening or treatment performed in one of five contexts, pre-biologic or other immunosuppression screening, people living with HIV, TB case contacts, other vulnerable populations, or healthcare workers. The risk of bias across studies with regard to prevalence of LTBI was generally high. One study reported a complete cascade of LTBI care from screening initiation to treatment completion. This systematic review has described what published research there is on the epidemiology and cascade of LTBI care in Ireland and identified knowledge gaps. A strategy for addressing these knowledge gaps has been proposed.

Compliance of Healthcare Worker's toward Tuberculosis Preventive Measures in Workplace: A Systematic Literature Review

Despite several guidelines published by the World Health Organization (WHO) and national authorities, there is a general increase in the number of healthcare workers (HCWs) contracting tuberculosis. This review sought to evaluate the compliance of the HCWs toward tuberculosis preventive measures (TPMs) in their workplace. Both electronic databases and manual searches were conducted to retrieve articles regarding the compliance of HCWs in the workplace published from 2010 onwards. Independent reviewers extracted, reviewed, and analyzed the data using the mixed methods appraisal tool (MMAT) 2018, comprising 15 studies, 1572 HCWs, and 249 health facilities. The results showed there was low compliance toward TPMs in the workplace among HCWs and health facilities from mostly high-burden tuberculosis countries. The failure to comply with control measures against tuberculosis was mainly reported at administrative levels, followed by engineering and personnel protective control measures. In addition, low managerial support and negative attitudes of the HCWs influenced the compliance. Further studies are needed to elucidate how to improve the compliance of HCWs toward the preventive measures against tuberculosis in order to reduce the disease burden among HCWs worldwide.

Occupational Infections among Dental Health Workers in Germany-14-Year Time Trends

Dental health workers (DHW) are at increased risk of acquiring occupational infections. Due to various protective measures, it can be assumed that infections have decreased over the past 14 years. Secondary data from a German accident insurance company was analyzed in terms of reported and confirmed occupational diseases (OD) in DHW from 2006 to 2019. A total of 271 claims were reported, of which 112 were confirmed as OD, representing an average of eight per year. However, the number of claims and confirmed ODs has decreased by 65.6% and 85.7%, respectively. The decrease was most evident for hepatitis B (HBV) and C (HCV) infections, while tuberculosis (TB) infections were stable. A total of 44 HCV, 33 HBV, 6 TB and 24 latent TB infections were confirmed as ODs. For DHW, 0.05, and for hospital workers, 0.48 claims per 1000 full-time equivalents (FTE) were registered in 2019. In a separate documentation system, between March 2020 and February 2021, 155 COVID-19 claims were registered, and 47 cases were confirmed as ODs. For DHW, 0.7, and for hospital workers, 47.3 COVID-19 claims per 1000 FTE were registered since 2020. Occupational infectious diseases rarely occur among DHW. Nevertheless, new infectious diseases such as COVID-19 pose a major challenge for DHW. Continued attention should be paid to infectious disease prevention.

Upregulation of PD-1 expression on circulating CD8+ but not CD4+ T cells is associated with tuberculosis infection in health care workers

Background

Health care workers (HCWs) are at risk for occupationally acquired Mycobacterium tuberculosis infection and tuberculosis (TB) disease due to repeated exposure to workplace tubercle bacilli. To determine whether continual mycobacterial stimulation correlates with increased expression of inhibitory T cell receptors, here we compared PD-1 receptor expression on surfaces of circulating T cells between naïve (uninfected) HCWs and HCWs with latent TB infection (LTBI).

Result

Data collected from 133 medical workers who met study selection criteria were included in the final analysis. QuantiFERON-TB Gold In-​Tube (QFT-GIT) testing yielded positive results for 32 HCWs, for an overall LTBI rate of 24.1%. Multivariate analysis identified HCW length of service > 15 years as an independent risk factor for a positive QFT-GIT result. In addition, comparisons of blood T cell subgroup profiles between QFT- and QFT+ groups indicated QFT+ subjects possessed greater proportions of mature (TM), transitional memory (TTM) and effector memory (TEM) CD4+ T cell subgroups and lower proportions of naïve T cells (TN). Moreover, the QFT+ group percentage of CD8+ T cells with detectable surface PD-1 was significantly higher than the corresponding percentage for the QFT- group. Meanwhile, no statistical intergroup difference was observed in percentages of CD4+ T cells with detectible surface PD-1.

Conclusions

Our data demonstrated that upregulated PD-1 expression on circulating CD8+, but not CD4+ T cells, was associated with latent TB infection of HCWs. As compared to other hospitals, occupational TB infection risk in our hospital was substantially mitigated by implementation of multitiered infection control measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00433-9.

Tuberculin Skin Testing versus Interferon-Gamma Release Assay among Users of a Public Health Unit in Northeast Portugal

The screening of groups with a high risk for developing tuberculosis (TB) is a priority in order to control this disease. Since there is no gold standard for the diagnosis of latent TB infection (LTBI), both the tuberculin skin test (TST) and the interferon-gamma release assays (IGRA) have been used for this purpose. The aim of this study was to determine the proportion of LTBI by using the TST and the IGRA tests, and to assess the risk factors related with discordant results between tests across several risk groups advised for screening in Northeast Portugal. Data were collected from the database of patients with suspected LTBI and advised for the screening in a public health unit (January 2014 to December 2015). The proportion of LTBI was computed using both tests. Logistic regression models assessed risk factors for a positive test and for discordant results between tests. The adjusted odds ratio (OR) and respective 95% confidence interval (95% CI) were obtained. Out of 367 patients included in the analysis, 79.8% had a positive TST and 46.0% of them had a positive IGRA. In comparison with contacts of active TB cases, healthcare workers and inmates presented higher odds of TST positivity (OR 4.38, 95% CI 1.59–12.09 and OR 4.74, 95% CI 1.45–15.49, respectively), but immunocompromised people presented lower odds of TST positivity (OR 0.14; 95% CI 0.06–0.31). Instead, healthcare workers (OR 0.44, 95% CI 0.24–0.80) and immunocompromised people (OR 0.24, 95% CI 0.10–0.56) presented lower odds of a positive IGRA. There were 42.0% concordant positive results, 16.1% concordant negative results, and 41.9% discordant results, with healthcare workers presenting higher odds of discordant results (OR 3.34, 95% CI 1.84–6.05). The proportion of LTBI estimated by TST and IGRA among people advised for screening in our setting is high, highlighting the need of preventive strategies. Among healthcare workers, TST results should be read with caution as the higher proportion of discordant results with a positive TST suggests the impact of the booster reaction in this group.

Serial testing of health care workers for tuberculosis infection: A prospective cohort study

Health Care Workers (HCW) may have an occupational risk of latent tuberculosis infection (LTBI) and TB disease. The objective of this study was to evaluate the performance of the 2-step strategy: tuberculin skin test (TST) followed by confirmation with Interferon (IFN)-γ- release assays (IGRAs) in HCW. A secondary objective was to determine the factors related to conversions and reversions. HCW at risk of occupational exposure who attended the Occupational Department of the Hospital Germans Trias i Pujol were included during the study period (2013-2016). All professionals testing negative for LTBI were included in a cohort study. These workers were followed up with the administration of a TST and an IGRA quantification at least one year after inclusion in the study. Workers with positive TST, regardless of the results of the IGRA tests, were followed-up with an IGRA. 255 workers were enrolled in the study and 108 workers from the same cohort were followed up. During the follow-up period, seven workers presented TST test conversion. One of these conversions was also confirmed by an IGRA test. There were 2 conversions of cases only testing positive with the IGRA. There have been only 2 reversions of cases testing negative with the IGRA. In this study, not all TST conversions were confirmed when using the IGRA test, which highlights the importance of the 2-step strategy. We have detected a low number of conversions and reversions. Our conclusions should be confirmed in studies with a longer follow-up time.

Risk Analysis of Latent Tuberculosis Infection among Health Workers Compared to Employees in Other Sectors

Latent tuberculosis infection (LTBI) represents a work-related risk for health workers (HWs). Tuberculosis remains the second most common occupational infectious disease among HWs in Germany. Comparative figures on LTBI prevalence in the general population are missing because testing is only carried out in the context of an outbreak situation. The objective of this study is to investigate whether HWs are at greater risk of LTBI than workers in other sectors. This study is based on two samples. The first sample is a database of HWs who were examined by the German Occupational Physicians Network using an interferon-gamma release assay (IGRA). The second sample consists of general employees (non-health workers, non-HWs) from Hamburg who had no professional contact with the health care system. Propensity score matching (PS matching) was performed to ensure better comparability of the groups. The differences in the prevalence of positive test results from IGRAs were examined using univariate and multivariate analyses. After the PS matching of 1:10, 100 test subjects in the non-HW group and 1000 HWs remained to form the analysis collective. The HWs tended to exhibit higher IGRA values than non-HWs. The univariate analysis showed an odds ratio (OR) of 3.86 for the HWs (95% confidence interval (CI): 0.99 to 32.5; p = 0.056) with respect to a positive test result. The multivariate analysis produced an OR of 4.92, (95% CI: 1.3 to 43.7; p = 0.013) for HWs born in Germany. Despite the declining tuberculosis incidence rates in Germany, a comparison with non-exposed professional groups showed that HWs are at greater risk of LTBI. Preventive medical check-ups still seem to be indicated.

Immunoassay of interferon gamma by quartz crystal microbalance biosensor

Interferon gamma (IFNγ) is a cytokine and an immunochemical marker that can be used for revealing of infectious diseases and especially for distinguishing of viral and some types of bacterial infections. Blood tests for IFNγ are typically based on immunoassays like Enzyme-Linked Immunosorbent Assay (ELISA). In this paper, a biosensor working on the principle of quartz crystal microbalance (QCM) was developed as an alternative to the standard analytical methods for IFNγ. The biosensor contained antibodies against IFNγ immobilized on QCM and also on gold nanoparticles. A sandwich containing QCM, gold nanoparticles and IFNγ was formed and formation of the sandwich caused decrease of oscillation frequency. The assay exerted limit of detection 5.7 pg/ml for a sample sized 50 μl and one measuring cycle was finished within 90 min. The assay by biosensor fully correlated to standard ELISA. In a conclusion, the biosensor appears to be a fully applicable analytical tool for a simple assay of IFNγ. Overall simplicity and no special requirement on staff and equipment are the major advantages of the here presented assay.

Tuberculosis among Health Workers-A Secondary Data Analysis of German Social Accident Insurance Data from 2002-2017

Tuberculosis (TB) is the most common cause of fatal infections worldwide. Recent TB figures in Europe indicate that 30 people were infected with tuberculosis each hour in 2017. Healthcare workers are at particular risk of being infected through patient contact. TB is the second most common occupational infectious disease among German healthcare workers. Routine data from the German Social Accident Insurance were used to examine trends in occupational TB diseases. We analyzed annual cross-sectional data for the years 2002 to 2017. The data underwent descriptive analysis. A total of 4653 TB cases were recognized as occupational diseases (OD) in the period under study. In 2002, 60 TB cases were recognized as OD No. 3101, i.e., transmissions from person to person. Since 2013, the level has settled at around 500 recognized cases per year. This is around eight times the number of cases compared to 2002. The following three groups collectively accounted for the largest share of TB cases (88.5%): nurses (including geriatric nurses), other healthcare employees, and physicians. The upward trend in the number of TB cases recognized as occupational diseases is probably due to improvements in diagnostic tests used to diagnose TB infections. TB in health and welfare workers remains an important issue in the health and welfare sector in Germany, partly due to the long latency period between potential exposure to infectious patients or materials and the recognition of the latent tuberculosis infection (LTBI) or active TB as OD.