Incidence of occupational latent tuberculosis infection in South African healthcare workers

Hazard Vulnerabilities Analysis in the Low-Resourced Global Setting

A hazard vulnerabilities analysis (HVA) is an exercise used by institutions to identify potential threats and is required for credentialing hospitals in the US. To date, there is no documentation of HVA completion in low/middle income countries (LMIC) in the literature. American physicians working together with local physicians and staff from a major referral hospital in Addis Ababa, Ethiopia conducted an HVA in the LMIC setting. Using the Kaiser HVA template, the tool and exercise were tailored to the needs and resources of the LMIC setting. The exercise prompted rich discussion and facilitated the development of a framework to address local hospital threats. Many threats were considered sub-acute or chronic problems that had potential to acutely worsen, putting hospital operations and patient care in jeopardy and impacting staff. Ongoing threats were addressed creatively by the hospital administration, caregivers, and staff, a testament to the resiliency of the system and those working in it. Nonetheless, the hospital benefited from the HVA framework to improve future preparedness. Conducting an HVA in the LMIC setting is feasible, and this example can serve as a basis for HVA completion by other hospitals in similar settings.

Latent Tuberculosis Infections in Different Intensity of Exposure within Moroccan Population: Influence of Age and Bacille Calmette-Guérin Vaccination

BACKGROUND

In Morocco, latent tuberculosis infection (LTBI) is a public health concern affected by the country's location as transit area between sub-Saharan Africa with high TB burden to Europe. This study aimed to assess the influence of exposure intensity to Mycobacterium tuberculosis (Mtb), age, and Bacille Calmette-Guérin (BCG) vaccination on LTBI prevalence in Morocco.

METHODS

A cross-sectional study of 131 participants, including 98 non-exposed healthy volunteers (NEHV) and 33 healthcare workers exposed to active TB (exposed healthcare workers [EHCW]), was conducted. The Interferon-γ Release Assay (IGRA) was used to detect LTBI, and results were analyzed according to participants' age and BCG vaccination status.

RESULTS

EHCW showed a higher prevalence of LTBI than NEHV (36.7% vs. 57.6%) and of EHCW were positive for LTBI. In both groups, the mean age of those with LTBI was higher than those without. Furthermore, we showed within both groups, that LTBI prevalence was positively associated with subjects less covered by BCG vaccination in comparison with subjects likely totally covered by this vaccination (adjusted odds ratio [aOR], 2.783; 95% confidence intervals [CI], 1.180-6.57; P = 0, 01), (aOR, 6.717; 95% CI, 1.254-35.977; P = 0.02).

CONCLUSION

Our results showed that in the Moroccan TB epidemic context, the prevalence of LTBI still lower among healthy adults general population than within EHCW. Furthermore, this LTBI showed to be positively impacted by age in the two condition of exposure. We also showed that BCG vaccination seems to affect the prevalence of LTBI within both high and low intensity of exposure to Mtb infection.

Changes in the rate of bacillus tuberculosis infection in health workers in the first year of the COVID-19 epidemic in Kashan- Iran

Objective

This cohort study aimed to determine the prevalence and risk factors of latent tuberculosis infection among healthcare workers during the COVID-19 pandemic.

Methods

A one-year cohort study was conducted in a referral hospital in Kashan, involving 176 medical, educational, and cleaning personnel. Initial evaluations and tuberculin skin tests were performed, followed by a one-year follow-up period. Data were analyzed using SPSS version 26 software.

Results

Among the participants, 26.1% (46 individuals) tested positive for latent tuberculosis infection. Age was a significant risk factor, with a 3.6% increase in latent tuberculosis infection risk with each advancing year. Men had 2.19 times (1.10-4.35) the chance of having a latent infection compared to women. Hospital staff were 3.7 times more at risk of tuberculosis infection than students. Among the hospital job categories, nursing assistants had the highest chance of tuberculosis infection, 6.77 times higher than medical students, followed by cleaning staff and nurses. The ICU, General, and Obstetrics and Gynecology departments had an infection chance of 2.46 (1.11-5.46) compared to other departments. No new positive cases were detected during the follow-up period.

Conclusion

This study contributes to the understanding of latent tuberculosis infection prevalence and its risk factors among healthcare workers during the COVID-19 pandemic. The findings highlight the importance of infection control measures and targeted interventions to protect healthcare workers from occupational tuberculosis exposure.

Prevalence of Latent Tuberculosis Infection and its Associated Factors Among Diabetic Patients Availing Primary Health Care in Terengganu State, Malaysia

Objectives

Diabetes mellitus (DM) patients are considered to be at high risk for contracting latent tuberculosis infection (LTBI). This study aimed to determine the prevalence of LTBI and its associated factors among diabetic patients attending primary care clinics in Terengganu state, Malaysia.

Methods

This cross-sectional study was conducted among diabetic patients attending 11 health clinics in the Terengganu region from June 2017 to November 2018. The selected participants were administered a tuberculin skin test (TST). Simple and multivariate logistic regressions were applied to evaluate the significant associated factors of LTBI.

Results

The total number of participants were 703 DM patients. The factors found associated with LTBI were poor diabetic control status (odds ratio (OR) = 8.53; p=0.008), being a healthcare worker (OR = 7.91; p=0.001), history of contact with TB patients (OR = 5.69; p < 0.001), bronchial asthma (OR = 5.28; p=0.019), coronary heart disease (OR = 3.45; p=0.026), and nephropathy (OR = 0.34; p=0.040). The presence of LTBI was found in 34 (4.8%) participants.

Conclusions

At 4.8%, the prevalence of LTBI among DM patients in Terengganu is relatively low. Diabetics with poorly controlled blood glucose levels, nephropathy, bronchial asthma, coronary heart disease, history of TB patient contact, or working in the healthcare profession should be periodically tested for LTBI.

Mycobacterium tuberculosis infection and disease in healthcare workers in a tertiary referral hospital in Bandung, Indonesia

Background

Healthcare workers (HCWs), especially in high tuberculosis (TB) incidence countries, are at risk of Mycobacterium tuberculosis infection and TB disease, likely due to greater exposure to TB cases and variable implementation of infection control measures.

Aim

We aimed to estimate the prevalence of tuberculin skin test (TST) positivity, history of TB and to identify associated risk factors in HCWs employed at a tertiary referral hospital in Bandung, Indonesia.

Methods

A cross-sectional study was conducted from April to August 2018. A stratified sample of the HCWs were recruited, screened by TST, assessed for TB symptoms, history of TB disease and possible risk factors. Prevalence of positive TST included diagnosis with TB after starting work. HCWs with TB disease diagnosed earlier were excluded. Survey weights were used for all analyses. Possible risk factors were examined using logistic regression; adjusted odds ratios and 95% confidence intervals (CI) are presented.

Results

Of 455 HCWs recruited, 42 reported a history of TB disease (25 after starting work) and 395 had a TST result. The prevalence of positive TST was 76.9% (95% CI 72.6-80.8%). The odds increased by 7% per year at work (95% CI 3-11%) on average, with a rapid rise in TST positivity up to 10 years of work and then a plateau with around 80% positive.

Discussion

A high proportion of HCWs had a history of TB or were TST positive, increasing with longer duration of work. A package of TB infection control measures is needed to protect HCWs from Mycobacterium tuberculosis infection.

Predicting Airborne Infection Risk: Association Between Personal Ambient Carbon Dioxide Level Monitoring and Incidence of Tuberculosis Infection in South African Health Workers

BACKGROUND

High rates of tuberculosis (TB) transmission occur in hospitals in high-incidence countries, yet there is no validated way to evaluate the impact of hospital design and function on airborne infection risk. We hypothesized that personal ambient carbon dioxide (CO2) monitoring could serve as a surrogate measure of rebreathed air exposure associated with TB infection risk in health workers (HWs).

METHODS

We analyzed baseline and repeat (12-month) interferon-γ release assay (IGRA) results in 138 HWs in Cape Town, South Africa. A random subset of HWs with a baseline negative QuantiFERON Plus (QFT-Plus) underwent personal ambient CO2 monitoring.

RESULTS

Annual incidence of TB infection (IGRA conversion) was high (34%). Junior doctors were less likely to have a positive baseline IGRA than other HWs (OR, 0.26; P = .005) but had similar IGRA conversion risk. IGRA converters experienced higher median CO2 levels compared to IGRA nonconverters using quantitative QFT-Plus thresholds of ≥0.35 IU/mL (P < .02) or ≥1 IU/mL (P < .01). Median CO2 levels were predictive of IGRA conversion (odds ratio [OR], 2.04; P = .04, ≥1 IU/mL threshold). Ordinal logistic regression demonstrated that the odds of a higher repeat quantitative IGRA result increased by almost 2-fold (OR, 1.81; P = .01) per 100 ppm unit increase in median CO2 levels, suggesting a dose-dependent response.

CONCLUSIONS

HWs face high occupational TB risk. Increasing median CO2 levels (indicative of poor ventilation and/or high occupancy) were associated with higher likelihood of HW TB infection. Personal ambient CO2 monitoring may help target interventions to decrease TB transmission in healthcare facilities and help HWs self-monitor occupational risk, with implications for other airborne infections including coronavirus disease 2019.

Tuberculosis infection status and risk factors among health workers: an updated systematic review

Tuberculosis (TB) infection is a common occupational risk for health workers (HWs) and poses a threat to the patients under their care and to other HWs. Hence, the development of a prevention strategy is crucial. We conducted a study to understand the status and risk factors of TB infection among HWs. The existing literature was searched for all published reports from 1 August 2010 to 31 December 2018, related to TB among HWs according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The inclusion criteria were: (1) study participants working in a health care facility; (2) TB cases diagnosed by medical professionals; (3) original research articles; and (4) English reports in a peer-reviewed journal. We finally included 61 studies from 642 articles searched initially. The TB infection rate in HWs was higher than that of the general population. Based on 39 studies, the prevalence of TB in HWs (tuberculin skin test positive) was 29.94%. In contrast, the global burden of latent TB infection was 23.0% (95% uncertainty interval: 20.4%–26.4%) in 2014. The risk factors of TB among HWs were aging, long duration of employment, nursing professionals, lack of Bacillus Calmette-Guerin vaccination, and low body mass index. HWs have an increased risk for TB infection, which can cause secondary infections in patients or other HWs. An effective prevention strategy must be developed to enable early diagnosis and prompt treatment.

A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2

SUMMARY

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles <10 µm that can remain suspended for hours before being inhaled. Because particulate filtering facepiece respirators ('respirators'; e.g. N95 masks) are more effective than surgical masks against bio-aerosols, many international organisations now recommend that health workers (HWs) wear a respirator when caring for individuals who may have COVID-19. In South Africa (SA), however, surgical masks are still recommended for the routine care of individuals with possible or confirmed COVID-19, with respirators reserved for so-called aerosol-generating procedures. In contrast, SA guidelines do recommend respirators for routine care of individuals with possible or confirmed tuberculosis (TB), which is also transmitted via aerosol. In health facilities in SA, distinguishing between TB and COVID-19 is challenging without examination and investigation, both of which may expose HWs to potentially infectious individuals. Symptom-based triage has limited utility in defining risk. Indeed, significant proportions of individuals with COVID-19 and/or pulmonary TB may not have symptoms and/or test negative. The prevalence of undiagnosed respiratory disease is therefore likely significant in many general clinical areas (e.g. waiting areas). Moreover, a proportion of HWs are HIV-positive and are at increased risk of severe COVID-19 and death.

RECOMMENDATIONS

Sustained improvements in infection prevention and control (IPC) require reorganisation of systems to prioritise HW and patient safety. While this will take time, it is unacceptable to leave HWs exposed until such changes are made. We propose that the SA health system adopts a target of 'zero harm', aiming to eliminate transmission of respiratory pathogens to all individuals in every healthcare setting. Accordingly, we recommend: the use of respirators by all staff (clinical and non-clinical) during activities that involve contact or sharing air in indoor spaces with individuals who: (i) have not yet been clinically evaluated; or (ii) are thought or known to have TB and/or COVID-19 or other potentially harmful respiratory infections;the use of respirators that meet national and international manufacturing standards;evaluation of all respirators, at the least, by qualitative fit testing; andthe use of respirators as part of a 'package of care' in line with international IPC recommendations. We recognise that this will be challenging, not least due to global and national shortages of personal protective equipment (PPE). SA national policy around respiratory protective equipment enables a robust framework for manufacture and quality control and has been supported by local manufacturers and the Department of Trade, Industry and Competition. Respirator manufacturers should explore adaptations to improve comfort and reduce barriers to communication. Structural changes are needed urgently to improve the safety of health facilities: persistent advocacy and research around potential systems change remain essential.

"If I've got latent TB, I would like to get rid of it": Derivation of the CARD (Constraints, Actions, Risks, and Desires) Framework informed by South African healthcare worker perspectives on latent tuberculosis treatment

BACKGROUND

Healthcare workers (HWs) have at least twice the risk of tuberculosis (TB) compared to the general population. There is growing emphasis on latent TB infection (LTBI) in high-risk populations. Yet we know little about HWs' perspectives of LTBI testing and treatment to inform implementation in high-incidence settings. We developed a qualitative networked approach to analyze HWs' perspectives on LTBI testing and treatment.

METHODS

We conducted 22 in-depth interviews with nurse and physician stakeholders, who had been recruited as part of a larger study evaluating TB transmission risk in HWs at Tygerberg Hospital, Cape Town, South Africa. We performed open coding to identify emergent themes and selective coding to identify relevant text citations. We used thematic analysis to inductively derive the CARD (Constraints, Actions, Risks, Desires) framework.

RESULTS

All HWs desired to avoid developing TB but few felt this was actionable. Despite LTBI knowledge gaps, safety and cost concerns, most HWs reported hypothetical willingness to take LTBI treatment. The CARD framework showed that desire and action related to LTBI testing and treatment was clearly framed by the interactions between constraints, administrative action, and risk. The surprise HWs described on receiving a negative LTBI (Quantiferon-Plus) result suggests LTBI testing may recalibrate HWs' perceptions regarding the futility of actions to reduce their TB risk.

CONCLUSIONS

LTBI testing and treatment are acceptable to HWs and could counteract the perceived inevitability of occupational TB infection that currently may limit risk reduction action. This should be coupled with administrative leadership and infrastructural support. The CARD analytic framework is a helpful tool for implementation scientists to understand current practices within complex health systems. Application of CARD could facilitate the development of contextually-relevant interventions to address important public health problems such as occupational TB.

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.

Prevalence of latent tuberculosis infection among health workers in Afghanistan: A cross-sectional study

BACKGROUND

About 26% of the world's population may have latent tuberculosis infection (LTBI). Health care workers are a high-risk category because of their professional exposure.

METHODS

This cross-sectional study assessed the LTBI burden among health care workers in Afghanistan, a high-TB-burden country. We selected health facilities using a systematic sampling technique and invited all workers at the targeted health facilities to participate. Participants were interviewed about sociodemographic and exposure variables and received tuberculin skin tests for LTBI.

RESULTS

Of the 4,648 health care workers invited to participate, 3,686 had tuberculin skin tests. The prevalence of LTBI was found to be 47.2% (1,738 workers). Multivariate analysis showed that a body mass index of ≥ 30 and marriage were associated with an increased risk of LTBI. Underweight (body mass index of ≤ 18 and below) and normal body mass index had no association with increased risk of LTBI.

CONCLUSION

LTBI is high among health care workers in Afghanistan. We recommend instituting infection control measures in health facilities and screening workers for timely TB diagnosis.

Isolation measures and protection awareness are significant for latent tuberculosis infection: a cross-sectional study based on T-SPOT.TB among health care workers in China

This study aimed to reveal the associated risk factors for latent tuberculosis infection (LTBI) detected by T-SPOT.TB assay among health care workers (HCWs) at different working locations or job categories in China. This cross-sectional study included 934 HCWs who underwent the T-SPOT.TB assay. Demographic and social characteristics of the participants, including age, sex, job categories, department/ward and duration of healthcare service, were recorded. Among 934 HCWs, 267 (28.5867%) were diagnosed as having LTBI with positive T-SPOT.TB assay. HCWs working in inpatient tuberculosis (TB) (odds ratio (OR) 2.917; 95% confidence interval (CI) 1.852–4.596; P < 0.001) and respiratory wards (OR 1.840; 95% CI 1.124–3.011; P = 0.015), and with longer duration of healthcare service (OR 1.048; 95% CI 1.016–1.080; P = 0.003) were risk factors for positive T-SPOT.TB result. Furthermore, longer working duration increased the positive rate of T-SPOT.TB results for physicians and nurses, and physicians had higher risks than nurses for the same working duration. Inpatient TB and respiratory wards were high-risk working locations for HCWs with LTBI, and longer duration of healthcare service also increased the risk of LTBI among HCWs. A complete strategy for TB infection control and protection awareness among HCWs should be enhanced.

Occupational Tuberculosis Among Laboratory Workers in South Africa: Applying a Surveillance System to Strengthen Prevention and Control

Background: Tuberculosis (TB) is recognized as an important health risk for health workers, however, the absence of occupational health surveillance has created knowledge gaps regarding occupational infection rates and contributing factors. This study aimed to determine the rates and contributing factors of active TB cases in laboratory healthcare employees at the National Health Laboratory Service (NHLS) in South Africa, as identified from an occupational surveillance system. Methods: TB cases were reported on the Occupational Health and Safety Information System (OHASIS), which recorded data on occupation type and activities and factors leading to confirmed TB. Data collected from 2012 to 2019 were used to calculate and compare TB risks within NHLS occupational groups. Results: During the study period, there were 92 cases of TB identified in the OHASIS database. General workers, rather than skilled and unskilled laboratory workers and medical staff, had the highest incidence rate (422 per 100,000 person-years). OHASIS data revealed subgroups that seemed to be well protected, while pointing to exposure situations that beckoned policy development, as well as identified subgroups of workers for whom better training is warranted. Conclusions: Functional occupational health surveillance systems can identify subgroups most at risk as well as areas of programme success and areas where increased support is needed, helping to target and monitor policy and procedure modification and training needs.

The Prevalence and Demographic Risk Factors for Latent Tuberculosis Infection (LTBI) Among Healthcare Workers in Semarang, Indonesia

Purpose

To determine the prevalence and demographic risk factors for latent tuberculosis infection (LTBI) among healthcare workers in Semarang, Indonesia.

Methods

A cross-sectional study involving 195 healthcare workers from 34 primary health centers was conducted from August to October 2019. The relationship between independent variables and dependent variables was analyzed using a multivariable logistic regression analysis.

Results

The prevalence of LTBI among healthcare workers in this study was 23.6%. Comorbidities were the only risk factor for LTBI identified among other risk factors (OR=3.39, 95% CI: 0.99–11.62, p=0.04). Other demographic factors such as age (OR=0.93, 95% CI: 0.45–1.92, p=0.839), gender (OR=0.79, 95% CI: 0.23–2.72, p=0.708, smoking habits (OR=2.54, 95% CI: 0.52–12.38, p=0.247), and length of work (OR=1.43, 95% CI: 0.70–2.91, p=0.331) were not significant risk factors for LTBI.

Conclusion

Healthcare workers suffering from comorbidity have a high risk for tuberculosis infection, and should not work in areas where they would be exposed to patients with tuberculosis. Healthcare workers need to apply occupational safety standards during contact with TB patients or specimens to minimize the disease transmission.

Perceived Health System Barriers to Tuberculosis Control Among Health Workers in South Africa

Background

The healthcare workforce in high tuberculosis burden countries such as South Africa is at elevated risk of tuberculosis infection and disease with adverse consequences for their well-being and productivity. Despite the availability of international guidelines on protection of health workers from tuberculosis, research globally has focused on proximal deficiencies in practice rather than on health system barriers.

Objective

This study sought to elicit perceptions of informed persons within the health system regarding health system barriers to protecting health workers from tuberculosis.

Methods

Semi-structured interviews were conducted with 18 informants active in spheres related to workplace tuberculosis prevention and management in South Africa. Interviews were audio recorded and transcribed verbatim, validated and analysed to derive emergent themes. Responses were analysed using the World Health Organization building blocks as core elements of a health system bearing on protection of its health workforce.

Findings

The following health system barriers were identified by informants: leadership and governance were "top-down" and fragmented; lack of funding was a major barrier; there were insufficient numbers of staff trained in infection prevention and control and occupational health; occupational health services were not comprehensively available and the ability to sustain protective technologies was questioned. A cross-cutting barrier was lack of priority afforded to workforce occupational health associated with lack of accurate information on cases of TB among health workers.

Conclusions

We conclude that deficiencies in implementation of recommended infection control and tuberculosis management practices are unlikely to be corrected until health system barriers are addressed. More committed leadership from senior health system management and greater funding are needed. The process could be assisted by the development of indicators to characterise such barriers and monitor progress.

Preventive tuberculosis treatment effect on QuantiFERON TB-Gold in-tube testing in a high tuberculosis-endemic country: A clinical trial

BACKGROUND

Whether T-cell interferon-γ responses to Mycobacterium tuberculosis-specific antigens can be influenced by tuberculosis preventive treatment in a high-endemic country is uncertain.

METHODS

In this prospective, open-label, controlled study, 513 individuals with silicosis were randomly selected for TB preventive treatment with rifapentine and isoniazid or for observation. QuantiFERON-TB Gold in-tube (QFT-GIT) assay was used to measure IFN-γ response to M. tuberculosis antigens at baseline (T0) and at 6 (T1) and 33 (T2) months after completion of therapy.

RESULTS

A total of 220 subjects were included in the final analysis: 105 and 115 in the prevention and observation arms, respectively. The proportions of QFT-GIT reversion from baseline to T1 were similar in the prevention and observation arms (18.4% vs 12.8%, P=0.566). However, reversion from baseline to T2 was more frequent in the prevention arm than in the observation arm, but the difference was not significant (24.2% vs 6.3%, P=0.881). No significant difference was observed in the quantitative responses of QFT-GIT between the two arms during follow-up at T1 (P=0.648) and T2 (P=0.918).

CONCLUSIONS

Preventive tuberculosis treatment has no effect on interferon-γ responses measured by serial QFT-GIT assays in a high tuberculosis-endemic country.

CLINICAL TRIALS REGISTRATION

http://www.clinicaltrials.gov NCT02430259.

Continuity of care for TB patients at a South African hospital: A qualitative participatory study of the experiences of hospital staff

BACKGROUND

Ensuring effective clinical management and continuity of TB care across hospital and primary health-care services remains challenging in South Africa. The high burden of TB, coupled with numerous health system problems, influence the TB care delivered by hospital staff.

OBJECTIVE

To understand factors from the perspectives of hospital staff that influence the clinical management and discharge of TB patients, and to elicit recommendations to improve continuity of care for TB patients.

DESIGN

Participatory action research was used to engage hospital staff working with TB patients admitted to a central public hospital in the Western Cape province, South Africa. Data were collected through eight focus group discussions with nurses, junior doctors and ward administrators. Data analysis was done using Miles and Huberman's framework to identify emerging patterns and to develop categories with themes and sub-themes. The participants influenced all phases of the research process to inform better practices in TB clinical management and discharge planning at the hospital.

RESULTS

The emerging themes and sub-themes were categorized into two overall sections: The clinical care management process and the discharge and referral process. Nurses expressed a fear of exposure to TB and MDR-TB due to challenges in clinical and infection-prevention control. Clinical hierarchies, poor interdisciplinary teamwork, limited task shifting and poor communication interfered with effective clinical and discharge processes. A high workload, staff shortages and inadequate skills resulted in insufficient information and health education for TB patients and their caregivers. Despite awareness of the patients' socio-economic challenges, some aspects of care were not patient-centered, and caregivers were not included in discharge planning. Communication between the hospital and referral points was inefficient and poorly supported by information systems. Hospital staff recommended improved infection prevention and control practices and interdisciplinary teamwork in the hospital, that TB education for patients be integrated with hospital staff functions, with more patient-centered discharge planning, and improved communication across hospitals and primary health care levels.

CONCLUSIONS

Interdisciplinary teamwork, more patient-centered care, and better communication within the hospital and with primary health-care services are needed for improved continuity of care for TB patients. Further studies on factors contributing to, and interventions to improve, continuity of TB care in similar hospital settings are needed.

Evaluating Latent Tuberculosis Infection Test Performance Using Latent Class Analysis in a TB and HIV Endemic Setting

BACKGROUND

Given the lack of a gold standard for latent tuberculosis infection (LTBI) and paucity of performance data from endemic settings, we compared test performance of the tuberculin skin test (TST) and two interferon-gamma-release assays (IGRAs) among health-care workers (HCWs) using latent class analysis. The study was conducted in Cape Town, South Africa, a tuberculosis and human immunodeficiency virus (HIV) endemic setting Methods: 505 HCWs were screened for LTBI using TST, QuantiFERON-gold-in-tube (QFT-GIT) and T-SPOT.TB. A latent class model utilizing prior information on test characteristics was used to estimate test performance.

RESULTS

LTBI prevalence (95% credible interval) was 81% (71-88%). TST (10 mm cut-point) had highest sensitivity (93% (90-96%)) but lowest specificity (57%, (43-71%)). QFT-GIT sensitivity was 80% (74-91%) and specificity 96% (94-98%), and for TSPOT.TB, 74% (67-84%) and 96% (89-99%) respectively. Positive predictive values were high for IGRAs (90%) and TST (99%). All tests displayed low negative predictive values (range 47-66%). A composite rule using both TST and QFT-GIT greatly improved negative predictive value to 90% (range 80-97%).

CONCLUSION

In an endemic setting a positive TST or IGRA was highly predictive of LTBI, while a combination of TST and IGRA had high rule-out value. These data inform the utility of LTBI-related immunodiagnostic tests in TB and HIV endemic settings.

Tuberculosis infection risk, preventive therapy care cascade and incidence of tuberculosis disease in healthcare workers at Maputo Central Hospital

BACKGROUND

Mozambican healthcare workers have high rates of latent and active tuberculosis, but occupational screening for tuberculosis is not routine in this setting. Furthermore, the specificity of tuberculin skin testing in this population compared with interferon gamma release assay testing has not been established.

METHODS

This study was conducted among healthcare workers at Maputo Central Hospital, a public teaching quaternary care hospital in Mozambique. With a cross sectional study design, risk factors for tuberculosis were assessed using multivariable logistic regression. The care cascade is reported for participants who were prescribed six months of isoniazid preventive therapy for HIV or highly reactive testing for latent tuberculosis infection. The agreement of interferon-gamma release assay results with positive tuberculin skin testing was calculated.

RESULTS

Of 690 screened healthcare workers, three (0.4%) had active tuberculosis and 426 (61.7%) had latent tuberculosis infection. Less education, age 35-49, longer hospital service, and work in the surgery department were associated with increased likelihood of being tuberculosis infected at baseline (p < 0.05). Sex, Bacillus Calmette-Guerin vaccination, HIV, outside tuberculosis contacts, and professional category were not. Three new cases of active tuberculosis developed during the follow-up period, two while on preventive therapy. Among 333 participants offered isoniazid preventive therapy, five stopped due to gastrointestinal side effects and 181 completed treatment. For HIV seropositive individuals, the agreement of interferon gamma release assay positivity with positive tuberculin skin testing was 50% among those with a quantitative skin test result of 5-10 mm, and among those with a skin test result ≥10 mm it was 87.5%. For HIV seronegative individuals, the agreement of interferon gamma release assay positivity with a tuberculin skin test result of 10-14 mm was 63.6%, and for those with a quantitative skin test result ≥15 mm it was 82.2%.

CONCLUSIONS

There is a high prevalence of tuberculosis infected healthcare workers at Maputo Central Hospital. The surgery department was most heavily affected, suggesting occupational risk. Isoniazid preventive therapy initiation was high and just over half completed therapy. An interferon gamma release assay was useful to discern LTBI from false positives among those with lower quantitative tuberculin skin test results.

Latent tuberculosis infection in healthcare workers in low- and middle-income countries: an updated systematic review

Healthcare workers (HCWs) are at increased risk of latent tuberculosis (TB) infection (LTBI) and TB disease.We conducted an updated systematic review of the prevalence and incidence of LTBI in HCWs in low- and middle-income countries (LMICs), associated factors, and infection control practices. We searched MEDLINE, Embase and Web of Science (January 1, 2005-June 20, 2017) for studies published in any language. We obtained pooled estimates using random effects methods and investigated heterogeneity using meta-regression.85 studies (32 630 subjects) were included from 26 LMICs. Prevalence of a positive tuberculin skin test (TST) was 14-98% (mean 49%); prevalence of a positive interferon-γ release assay (IGRA) was 9-86% (mean 39%). Countries with TB incidence ≥300 per 100 000 had the highest prevalence (TST: pooled estimate 55%, 95% CI 41-69%; IGRA: pooled estimate 56%, 95% CI 39-73%). Annual incidence estimated from the TST was 1-38% (mean 17%); annual incidence estimated from the IGRA was 10-30% (mean 18%). The prevalence and incidence of a positive test was associated with years of work, work location, TB contact and job category. Only 15 studies reported on infection control measures in healthcare facilities, with limited implementation.HCWs in LMICs in high TB incidence settings remain at increased risk of acquiring LTBI. There is an urgent need for robust implementation of infection control measures.

Predictors of discordant latent tuberculosis infection test results amongst South African health care workers

BACKGROUND

The tuberculin skin test (TST) and interferon-gamma-release-assays (IGRAs) are utilized in screening programmes for presumed latent tuberculosis infection (LTBI) in health care workers (HCWs). However, inter-test comparison yields high rates of discordance, which is poorly understood. The aim of the study was therefore to identify factors associated with discordance amongst HCWs in a TB and HIV endemic setting.

METHODS

505 HCWs were screened for LTBI in South Africa using the TST and two IGRA assays (QuantiFERON-TB-Gold-In-Tube (QFT-GIT) and TSPOT.TB). Factors associated with discordance were analyzed using a multinomial logistic regression model.

RESULTS

TST-IGRA discordance was negatively associated with longer duration of employment for both TSPOT.TB (OR = 0.92; 95% confidence interval (CI) 0.85-0.99) and QFT-GIT (OR = 0.90; 95% CI 0.84-0.96). Marked test discordance occurred in HIV-infected individuals who were more likely to have TSPOT.TB + ve / TST-ve discordance (OR 4.44; 95% CI 1.14-17.27) or TSPOT.TB + ve / QFT-GIT-ve test discordance (OR 5.72; 95% CI 1.95-16.78). Those engaged in home care were less likely to have QFT-GIT + ve/TSPOT.TB -ve / discordance (OR 0.32; 95% CI 0.10-0.95).

CONCLUSION

The marked TST-IGRA and IGRA-IGRA discordance in HIV-infected individuals suggest greater sensitivity of TSPOT.TB in immunocompromised persons or potential greater reactivity of TSPOT.TB in this population.

Occupational tuberculosis in healthcare workers in sub-Saharan Africa: A systematic review

This article investigates the incidence, prevalence and factors associated with occupational tuberculosis (TB) in healthcare workers (HCWs) in sub-Saharan Africa (SSA). Studies were extracted from MEDLINE, PsycINFO, CINAHL, Cochrane Library, and SCOPUS databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement from inception to the 2^nd of June 2017. Twenty-one studies met the inclusion criteria. The median prevalence of latent TB infection in HCWS was 62% (IQR 22%) and the median incidence of TB disease was 3871/100,000 (IQR 9314/100,000). The risk factors associated with LTBI or active TB disease were workplace, history of contact with TB patients, and longer duration of employment. The findings of this review demonstrate that the risk of acquiring TB among HCWs in SSA is high. This may impact on the recruitment, longevity and retention of HCWs.

Effectiveness of control measures to prevent occupational tuberculosis infection in health care workers: a systematic review

Background

A number of guideline documents have been published over the past decades on preventing occupational transmission of tuberculosis (TB) infection in health care workers (HCWs). However, direct evidence for the effectiveness of these controls is limited particularly in low-and middle-income (LMIC) countries. Thus, we sought to evaluate whether recommended administrative, environmental and personal protective measures are effective in preventing tuberculin skin test conversion among HCWs, and whether there has been recent research appropriate to LMIC needs.

Methods

Using inclusion criteria that included tuberculin skin test (TST) conversion as the outcome and longitudinal study design, we searched a number of electronic databases, complemented by hand-searching of reference lists and contacting experts. Reviewers independently selected studies, extracted data and assessed study quality using recommended criteria and overall evidence quality using GRADE criteria.

Results

Ten before-after studies were found, including two from upper middle income countries. All reported a decline in TST conversion frequency after the intervention. Among five studies that provided rates, the size of the decline varied, ranging from 35 to 100%. Since all were observational studies assessed as having high or unclear risk of bias on at least some criteria, the overall quality of evidence was rated as low using GRADE criteria.

Conclusion

We found consistent but low quality of evidence for the effectiveness of combined control measures in reducing TB infection transmission in HCWs in both high-income and upper-middle income country settings. However, research is needed in low-income high TB burden, including non-hospital, settings, and on contextual factors determining implementation of recommended control measures. Explicit attention to the reporting of methodological quality is recommended.

Trial registration

This systematic review was registered with PROSPERO in 2014 and its registration number is CRD42014009087.

Reversion of QuantiFERON-TB Gold In-Tube test in individuals with and without prophylactic treatment for latent tuberculosis infection: A systematic review and meta-analysis

OBJECTIVES

Reversion of tuberculosis (TB) infection testing has been suggested to be associated with prophylactic treatment efficacy. However, evidences based on randomized controlled study were sparse.

METHODS

Studies on serial QuantiFERON-TB Gold In-Tube (QFT) test, among individuals with and without prophylactic treatment were identified in the databases of PubMed, MEDLINE and EMBASE up to 28 February 2018. The reversion rates were quantitatively summarized by means of meta-analysis using the random-effect model.

RESULTS

A total of 52 eligible studies were included in the meta-analysis on QFT test reversion rate among participants with (20 studies) and without (32 studies) prophylactic treatment. Summarized reversion rate was found to be 24.9% (95% confidence interval [CI]: 18.4-32.9%) and 25.3% (95% CI: 19.6-32.0%) for those completed or without treatment, respectively. When the analysis was restricted to the participants completed treatment, higher summarized rate of QFT reversion was found among those with longer course therapy (9INH vs. the other regimens), studies from Asia (vs. Europe and America), and individuals with immunosuppression disorders (vs. general populations).

CONCLUSIONS

Our results suggested that QFT reversion was frequently observed regardless of with or without prophylactic treatment. Serial QFT testing might be inappropriate for evaluating preventive treatment efficacy.

Latent tuberculosis infection and associated risk indicators in pastoral communities in southern Ethiopia: a community based cross-sectional study

BACKGROUND

Research pertaining to the community-based prevalence of latent tuberculosis infection (LTBI) is important to understand the magnitude of this infection. This study was conducted to estimate LTBI prevalence and to identify associated risk factors in the Omo Zone of Southern Ethiopia.

METHODS

A community-based cross-sectional study was conducted in six South Omo districts from May 2015 to February 2016. The sample size was allocated to the study districts proportional to their population sizes. Participants were selected using a multi-stage sampling approach. A total of 497 adult pastoralists were recruited. Blood samples were collected from the study participants and screened for LTBI using a U.S. Food and Drug Administration approved interferon-gamma release assay (IGRA). Logistic regression was used to model the likelihood of LTBI occurrence and to identify risk factors associated with LTBI.

RESULTS

The prevalence of LTBI was 50.5% (95% CI: 46%, 55%) with no significant gender difference (49.8% among males versus 51.2% among females; Chi-square (χ2) = 0.10; P = 0.41) and marginally non-significant increasing trends with age (44.6% among those below 24 years and 59.7% in the age range of 45-64 years; χ2 = 6.91; P = 0.075). Being residence of the Dasanech District (adjusted odds ratio, AOR = 2.62, 95% CI: 1.30, 5.28; P = 0.007) and having a habit of eating raw meat (AOR = 2.89, 95% CI: 1.09, 7.66; P = 0.033) were significantly associated with an increased odds of being positive for LTBI. A large family size (size of 5 to 10) has significant protective effect against associated a reduced odds of being positive for LTBI compared to a family size of below 5 (AOR = 0.65, 95% CI: 0.42, 0.99; P = 0.045).

CONCLUSIONS

A high prevalence of LTBI in the South Omo Zone raises the concern that elimination of TB in the pastoral communities of the region might be difficult. Screening for and testing individuals infected with TB, independent of symptoms, may be an effective way to minimize the risk of disease spread.

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.

BCG and New Preventive Tuberculosis Vaccines: Implications for Healthcare Workers

Healthcare workers (HCWs) are at high risk of Mycobacterium tuberculosis (Mtb) infection and tuberculosis disease, but also play a crucial role in implementing healthcare. Preexposure tuberculosis vaccination, including revaccination with BCG, might benefit Mtb-uninfected HCWs, but most HCWs in tuberculosis-endemic countries are already sensitized to mycobacteria. A new postexposure tuberculosis vaccine offers greatest potential for protection, in the setting of repeated occupational Mtb exposure. Novel strategies for induction of mycobacteria-specific resident memory T cells in the lung by aerosol administration, or induction of T cells with inherent propensity for residing in mucosal sites, such as CD1-restricted T cells and mucosa-associated innate T cells, should be explored. The need for improved protection of HCWs against tuberculosis disease is clear. However, health systems in tuberculosis-endemic countries would need significantly improved occupational health structures to implement a screening and vaccination strategy for HCWs.

Exposed, but Not Protected: More Is Needed to Prevent Drug-Resistant Tuberculosis in Healthcare Workers and Students

"Occupational MDR-TB"  …  "XDR-TB"  …  "Treatment-induced hearing loss": 3 life-changing messages imparted over the phone. Three personal accounts are shared highlighting the false belief held by many healthcare workers (HCWs) and students in low-resource settings-that they are immune to tuberculosis despite high levels of occupational tuberculosis exposure. This misconception reflects a lack of awareness of tuberculosis transmission and disease risk, compounded by the absence of accurate occupational tuberculosis estimates. As the global problem of drug-resistant (DR) tuberculosis evolves, HCWs are increasingly infected and suffer considerable morbidity and mortality from occupational DR tuberculosis disease. Similarly, healthcare students are emerging as a vulnerable and unprotected group. There is an urgent need for improved detection, vaccines, preventive therapy, treatment, and support for affected HCWs and those they care for, as well as destigmatization of all forms of tuberculosis. Finally, efforts to protect HCWs and prevent DR tuberculosis transmission by universal implementation of tuberculosis infection control measures should be prioritized.

Prevalence and risk factors of latent tuberculosis infection in Africa: a systematic review and meta-analysis protocol

INTRODUCTION

Latent tuberculosis infection (LTBI) remains a major public health problem and one of the major contributors to the pool of active tuberculosis cases. The true burden of LTBI in Africa is not known. Early modelling studies estimate that over 33% of the world's population is infected with latent tuberculosis. We propose conducting a systematic review and a meta-analysis to evaluate the burden and risk factors of LTBI in Africa reported in studies from 2000 to 2017.

METHODS AND ANALYSIS

We will include cross-sectional studies, cohort studies and case-control studies estimating either tuberculin skin test (TST) or interferon-gamma release assay (IGRA) confirmed prevalence of LTBI and associated risk factors among people in African countries. A comprehensive search of relevant literature will be conducted on electronic databases using common and medical subject heading (MeSH) terms for LTBI, and an African search filter. Risk of bias will be evaluated by assessing all qualifying full-text articles for quality and eligibility using a quality score assessment tool. Standardised data extraction will be carried out after which prevalence estimates will be pooled using random-effects models in Stata V.13. Where there is sufficient data , subgroup meta-analyses will be conducted by risk factors including participant's age group, occupation, location and HIV status. This systematic review will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses Protocols 2015 Statement.

ETHICS AND DISSEMINATION

No ethical issues were foreseen given that this was a protocol for a systematic review of published studies. The results of this study will be published in a peer-reviewed journal and presented at conferences.

TRIAL REGISTRATION NUMBER

Systematic review registration: PROSPERO CRD42016037997.

Prevalence and risk factors for latent tuberculosis infection among healthcare workers in Nampula Central Hospital, Mozambique

BACKGROUND

Healthcare workers in high tuberculosis burdened countries are occupationally exposed to the tuberculosis disease with uncomplicated and complicated tuberculosis on the increase among them. Most of them acquire Mycobacterium tuberculosis but do not progress to the active disease - latent tuberculosis infection. The objective of this study was to assess the prevalence and risk factors associated with latent tuberculosis infection among healthcare workers in Nampula Central Hospital, Mozambique.

METHODS

This cross-sectional study of healthcare workers was conducted between 2014 and 2015. Participants (n = 209) were administered a questionnaire on demographics and occupational tuberculosis exposure and had a tuberculin skin test administered. Multivariate linear and logistic regression tested for associations between independent variables and dependent outcomes (tuberculin skin test induration and latent tuberculosis infection status).

RESULTS

The prevalence of latent tuberculosis infection was 34.4%. Latent tuberculosis infection was highest in those working for more than eight years (39.3%), those who had no BCG vaccination (39.6%) and were immunocompromised (78.1%). Being immunocompromised was significantly associated with latent tuberculosis infection (OR 5.97 [95% CI 1.89; 18.87]). Positive but non-significant associations occurred with working in the medical domain (OR 1.02 [95% CI 0.17; 6.37]), length of employment > eight years (OR 1.97 [95% CI 0.70; 5.53]) and occupational contact with tuberculosis patients (OR 1.24 [95% CI 0.47; 3.27]).

CONCLUSIONS

Personal and occupational factors were positively associated with latent tuberculosis infection among healthcare workers in Mozambique.

Factors associated with good TB infection control practices among primary healthcare workers in the Free State Province, South Africa

Background

Despite the availability of TB infection control guidelines, and good levels of healthcare worker knowledge about infection control, often these measures are not well implemented. This study sought to determine the factors associated with healthcare workers’ good TB infection control practices in primary health care facilities in the Free State Province, South Africa.

Methods

A cross-sectional self-administered survey among nurses (n = 202) and facility-based community healthcare workers (n = 34) as well as facility observations were undertaken at all 41 primary health care facilities in a selected district of the Free State Province.

Results

The majority of respondents were female (n = 200; 87.7 %) and the average age was 44.19 years (standard deviation ±10.82). Good levels of knowledge were recorded, with 42.8 % (n = 101) having an average score (i.e. 65–79 %) and 31.8 % (n = 75) a good score (i.e. ≥ 80 %). Most respondents (n = 189; 80.4 %) had positive attitudes towards TB infection control practices (i.e. ≥ 80 %). While good TB infection control practices were reported by 72.9 % (n = 161) of the respondents (i.e. ≥75 %), observations revealed this to not necessarily be the case. For every unit increase in attitudes, good practices increased 1.090 times (CI:1.016–1.169). Respondents with high levels of knowledge (≥80 %) were 4.029 (CI: 1.550–10.469) times more likely to have good practices when compared to respondents with poor levels of knowledge (<65 %). The study did not find TB/HIV-related training to be a predictor of good practices.

Conclusions

Positive attitudes and good levels of knowledge regarding TB infection control were the main factors associated with good infection control practices. Although many respondents reported good infection control practices - which was somewhat countered by the observations - there are areas that require attention, particularly those related to administrative controls and the use of personal protective equipment.

Prevalence of Latent Tuberculosis among Health Care Workers in High Burden Countries: A Systematic Review and Meta-Analysis

Background

Tuberculosis is one of the leading causes of death worldwide. Twenty-two high burden countries contributed to the majority of worldwide tuberculosis cases in 2015. Health care workers are at high risk of acquiring tuberculosis through occupational exposure.

Objective

To estimate the prevalence of latent tuberculosis infection (LTBI) among health care workers in high burden countries.

Methods

Databases including MEDLINE (Ovid), EMBASE (Ovid), CINAHL (Ovid) and ISI Web of Science (Thompson-Reuters), and grey literature were searched for English language records on relevant medical subject headings (MeSH) terms of LTBI and health care providers. Literature was systematically reviewed using EPPI-Reviewer4 software. Prevalence and incidence of LTBI and 95% confidence intervals (CI) were reported. Pooled prevalence of LTBI and 95% CI were calculated using random-effects meta-analysis models and heterogeneity was assessed using I² statistics. Sub-group analysis was conducted to assess the cause of heterogeneity.

Results

A total of 990 records were identified. Of those, 18 studies from only 7 high burden countries representing 10,078 subjects were included. Tuberculin skin test results were available for 9,545 participants. The pooled prevalence of LTBI was 47% (95% CI 34% to 60%, I² = 99.6%). In subgroup analyses according to the country of the study, the pooled prevalence of LTBI was lowest in Brazil (37%) and highest in South Africa (64%). The pooled prevalence of LTBI among medical and nursing students was 26% (95% CI 6% to 46%, I² = 99.3%) while the prevalence among all types of health care workers was 57% (95% CI 44% to 70%, I² = 99.1%). Incidence of LTBI was available for health care workers in four countries. The cumulative incidence ranged from 2.8% in Brazilian medical students to 38% among all types of health care workers in South Africa.

Conclusion

The findings of this study suggest that there is a high burden of LTBI among health care workers in high burden countries. Adequate infection control measures are warranted to prevent and control transmission in health care settings.

The epidemiology of tuberculosis in health care workers in South Africa: a systematic review

BACKGROUND

In South Africa, workplace acquired tuberculosis (TB) is a significant occupational problem among health care workers. In order to manage the problem effectively it is important to know the burden of TB in health care workers. This systematic review describes the epidemiology of TB in South African health care workers.

METHODS

A comprehensive search of electronic databases [MEDLINE, EMBASE, Web of Science (Social Sciences Citation Index/Science Citation Index), Cochrane Library (including CENTRAL register of Controlled Trials), CINAHL and WHO International Clinical Trials Registry Platform (ICTRP)] was conducted up to April 2015 for studies reporting on any aspect of TB epidemiology in health care workers in South Africa.

RESULTS

Of the 16 studies included in the review, ten studies reported on incidence of active TB disease in health care workers, two report on the prevalence of active TB disease, two report on the incidence of latent TB infection, three report on the prevalence of latent TB infection and four studies report on the number of TB cases in health care workers in various health care facilities in South Africa. Five studies provide information on risk factors for TB in health care workers. All of the included studies were conducted in publicly funded health care facilities; predominately located in KwaZulu-Natal and Western Cape provinces. The majority of the studies reflect a higher incidence and prevalence of active TB disease in health care workers, including drug-resistant TB, compared to the surrounding community or general population.

CONCLUSIONS

There is relatively little research on the epidemiology of TB in health care workers in South Africa, despite the importance of the issue. To determine the true extent of the TB epidemic in health care workers, regular screening for TB disease should be conducted on all health care workers in all health care facilities, but future research is required to investigate the optimal approach to TB screening in health care workers in South Africa. The evidence base shows a high burden of both active and latent TB in health care workers in South Africa necessitating an urgent need to improve existing TB infection, prevention and control measures in South African health care facilities.

Tuberculosis

Although the worldwide incidence of tuberculosis has been slowly decreasing, the global disease burden remains substantial (∼9 million cases and ∼1·5 million deaths in 2013), and tuberculosis incidence and drug resistance are rising in some parts of the world such as Africa. The modest gains achieved thus far are threatened by high prevalence of HIV, persisting global poverty, and emergence of highly drug-resistant forms of tuberculosis. Tuberculosis is also a major problem in health-care workers in both low-burden and high-burden settings. Although the ideal preventive agent, an effective vaccine, is still some time away, several new diagnostic technologies have emerged, and two new tuberculosis drugs have been licensed after almost 50 years of no tuberculosis drugs being registered. Efforts towards an effective vaccine have been thwarted by poor understanding of what constitutes protective immunity. Although new interventions and investment in control programmes will enable control, eradication will only be possible through substantial reductions in poverty and overcrowding, political will and stability, and containing co-drivers of tuberculosis, such as HIV, smoking, and diabetes.

Sensitivity of C-Tb: a novel RD-1-specific skin test for the diagnosis of tuberculosis infection

C-Tb, a novel Mycobacterium tuberculosis and 6-kDa early secretory antigenic target/10-kDa culture filtrate protein (ESAT-6/CFP-10)-specific skin test, has high specificity in bacille Calmette-Guerin-vaccinated healthy controls. However, the sensitivity of C-Tb has hitherto not been determined. The objective was to determine the sensitivity of C-Tb in patients with active tuberculosis (TB) in comparison with the tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube (QFT-GIT).C-Tb and TST were randomly administered in a double-blinded fashion to one or the other forearm in 253 patients with active TB with or without HIV co-infection. QFT-GIT testing was performed prior to skin testing.Using a receiver operating characteristic curve-derived cut-point of 5 mm, C-Tb sensitivity was similar to QFT-GIT (73.9 (95% CI 67.8-79.3) versus 75.1 (95% CI 69.3-80.2)), and similar in HIV-infected and HIV-uninfected patients (76.7 (95% CI 69.0-83.3) versus 69.5 (95% CI 59.2-78.5)). However, sensitivity was significantly diminished in HIV-infected patients with CD4 counts <100 cells·mm(-3). C-Tb and QFT-GIT combined had significantly higher sensitivity than C-Tb alone (p<0.0001). C-Tb was safe with no significant adverse events. The 5 mm cut-point corresponded to that found in the previously published specificity study (TESEC-04).C-Tb has similar sensitivity compared with QFT-GIT for the diagnosis of M. tuberculosis infection. Sensitivity was reduced only in HIV-infected patients with severe immunosuppression. Further studies in different settings are required to validate the proposed 5 mm cut-point.