Tuberculosis Case Detection and Guideline Adherence among Child Contacts in Switzerland: A Retrospective Observational Study.

BACKGROUND: Children exposed to a tuberculosis (TB) index case are at risk of TB infection and disease. OBJECTIVES: The aim of this study was to describe the proportion of child contacts who developed TB infection or disease after exposure and to assess the diagnostic pathways and adherence to current guidelines. METHODS: Retrospective observational study including children ≤16 years of age who had contact to a TB index case between January 2019 and July 2021. Analysis was stratified by age groups 0-4, 5-11, and 12-16 years. RESULTS: Of 401 TB-exposed children, data were available for 380 (95%). Of those, 7 (2%) were diagnosed with TB disease and 35 (9%) with TB infection. We identified several deviations in the management compared to recommendations in national Swiss guidelines: In the children aged 0-4 years, only 82% were examined with an immunodiagnostic test or a chest radiography within 2 weeks after last contact. Recommended prophylactic treatment was prescribed in 66% of the children only. In the children aged 5-11 years, 64% were tested with an immunodiagnostic test in a first examination and 75% in a second examination, 2 weeks and 2 months after last contact, respectively. CONCLUSIONS: Contact investigations of children exposed to a TB index case identified a significant proportion of children with TB infection and disease in a low TB incidence setting. We observed significant deviations from the guidelines in the contact investigations suggesting the need for improved implementation.

Screening for Tuberculosis in Migrants: A Survey by the Global Tuberculosis Network.

Tuberculosis (TB) does not respect borders, and migration confounds global TB control and elimination. Systematic screening of immigrants from TB high burden settings and-to a lesser degree TB infection (TBI)-is recommended in most countries with a low incidence of TB. The aim of the study was to evaluate the views of a diverse group of international health professionals on TB management among migrants. Participants expressed their level of agreement using a six-point Likert scale with different statements in an online survey available in English, French, Mandarin, Spanish, Portuguese and Russian. The survey consisted of eight sections, covering TB and TBI screening and treatment in migrants. A total of 1055 respondents from 80 countries and territories participated between November 2019 and April 2020. The largest professional groups were pulmonologists (16.8%), other clinicians (30.4%), and nurses (11.8%). Participants generally supported infection control and TB surveillance established practices (administrative interventions, personal protection, etc.), while they disagreed on how to diagnose and manage both TB and TBI, particularly on which TBI regimens to use and when patients should be hospitalised. The results of this first knowledge, attitude and practice study on TB screening and treatment in migrants will inform public health policy and educational resources.

Defining Outcomes of Tuberculosis (Treatment): From the Past to the Future.

Untreated active tuberculosis (TB) has a very high long-term mortality. Treatment of TB reduces mortality dramatically and should maximize cure, preventing ongoing transmission and TB sequelae. However, predicting the risk of failure and relapse is crucial for the management of individual patients and for the evaluation of effectiveness of programs. Various outcome definitions for drug-sensitive and drug-resistant TB were developed, implemented, and endorsed since introduction of TB chemotherapy by the World Health Organization (WHO), mostly based on culture and smear results. They should be applicable for individual patient care, surveillance, and research. Definitions with focus on program evaluation differ from definitions to evaluate the efficacy and effectiveness of regimens. Lack of sputum production at the later stage of treatment reduces the easy applicability of current definitions. Definitions of failure and cure are sometimes difficult to apply. Alternative approaches suggest culture positivity at 6 months or more of treatment as an indicator for failure. New definitions for cure including a relapse-free period posttreatment and reduced number of culture and smear results are considered. Increasing variation and individualization of treatment and its duration urgently require new approaches using pathogen- or host-specific biomarkers, which indicate risk of failure and define cure. Such biomarkers are under evaluation but still far from translation in clinical routine practice.

Surveillance of Employees of Swiss Federal Asylum Centres for Latent Tuberculosis Infection.

BACKGROUND: Asylum seekers in Switzerland have to register in federal asylum centres (FACs) before formal permission to enter the country. Some of them may have active tuberculosis (TB), exposing fellow refugees and employees. OBJECTIVES: The aim of this study was to assess the risk of TB infection among employees of Swiss FACs. METHODS: Between 2010 and 2018, a free interferon-gamma release assay (IGRA) was offered to all employees of 8 FACs, at employment and at yearly intervals. We defined latent TB infection as IGRA conversion from negative to positive. IGRA-positive employees were referred to a medical centre for further clinical follow-up. RESULTS: 1,427 tests were performed among 737 employees (54.6% male). 403 (55%) persons were tested only once; 330 (44.5%) were tested several times; for 4 (0.5%) persons, the number of IGRA tests is unknown. Twenty employees (2.7%) had a positive IGRA at baseline, 2 (0.6%) converted from negative to positive during follow-up, resulting in an incidence of 22/10,000 person-years. We observed no case of active TB among employees. CONCLUSIONS: The prevalence of latent TB among employees to Swiss FACs and the risk of acquiring TB infection through work-related exposure are low. Yearly IGRA controls in the absence of documented TB exposure seem unnecessary.

Discovery and validation of a personalized risk predictor for incident tuberculosis in low transmission settings.

The risk of tuberculosis (TB) is variable among individuals with latent Mycobacterium tuberculosis infection (LTBI), but validated estimates of personalized risk are lacking. In pooled data from 18 systematically identified cohort studies from 20 countries, including 80,468 individuals tested for LTBI, 5-year cumulative incident TB risk among people with untreated LTBI was 15.6% (95% confidence interval (CI), 8.0-29.2%) among child contacts, 4.8% (95% CI, 3.0-7.7%) among adult contacts, 5.0% (95% CI, 1.6-14.5%) among migrants and 4.8% (95% CI, 1.5-14.3%) among immunocompromised groups. We confirmed highly variable estimates within risk groups, necessitating an individualized approach to risk stratification. Therefore, we developed a personalized risk predictor for incident TB (PERISKOPE-TB) that combines a quantitative measure of T cell sensitization and clinical covariates. Internal-external cross-validation of the model demonstrated a random effects meta-analysis C-statistic of 0.88 (95% CI, 0.82-0.93) for incident TB. In decision curve analysis, the model demonstrated clinical utility for targeting preventative treatment, compared to treating all, or no, people with LTBI. We challenge the current crude approach to TB risk estimation among people with LTBI in favor of our evidence-based and patient-centered method, in settings aiming for pre-elimination worldwide.

The diagnosis of latent tuberculosis infection (LTBI): currently available tests, future developments, and perspectives to eliminate tuberculosis (TB).

INTRODUCTION: Despite great efforts, tuberculosis (TB) is still a major public health threat worldwide. For decades, TB control programs have focused almost exclusively on infectious TB active cases.  However, it is evident that this strategy alone cannot achieve TB elimination. To achieve this objective a comprehensive strategy directed toward integrated latent tuberculosis infection (LTBI) management is needed. Recently it has been recognized that LTBI is not a stable condition but rather a spectrum of infections (e.g., intermittent, transient or progressive) which may lead to incipient, then subclinical, and finally active TB disease. AIM: Provide an overview of current available LTBI diagnostic test including updates, future developments and perspectives. RESULTS: There is currently no test for the direct identification of live MT infection in humans. The diagnosis of LTBI is indirect and relies on the detection of an immune response against MT antigens, assuming that the immune response has developed after a contact with the biological agent. Tuberculin skin test (TST) and interferon gamma release assays (IGRAs) are the main diagnostic tools for LTBI, however, both present strengths and limitations. The most ancient diagnostic test (TST) can be associated with several technical errors, has limited positive predictive value, is being influenced by BCG vaccination and several conditions can reduce the skin reactivity. Notwithstanding these limitations, prompt identification of TST conversion, should orientate indications for preventive therapy of LTBI. IGRAs have superior specificity, are not affected by M. bovis, BCG vaccination and other environmental mycobacteria. However, they present some logistical and organisational constraints and are more expensive. Currently, the WHO guidelines recommend that either a TST or an IGRA can be used to detect LTBI in high-income and upper middle-income countries with estimated TB incidences less than 100 per 100,000 population. Two skin tests (C-TB and Diaskintest), using only two specific M. tuberculosis antigens (ESAT-6 and CFP-10) instead of the tuberculin solution, have recently been developed but, to date, none of these tests is available on the European market. CONCLUSION: Early identification and treatment of individuals with LTBI is an important priority for TB control in specific groups at risk within the population: this is of crucial meaning in recently infected cases both at the community level and in some occupational settings. Currently there is no gold standard test for LTBI: an improved understanding of the available tests is needed to develop better tools for diagnosing LTBI and predicting progression to clinical active disease.

Epidemic and pandemic viral infections: impact on tuberculosis and the lung: A consensus by the World Association for Infectious Diseases and Immunological Disorders (WAidid), Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases Study Group for Mycobacterial Infections (ESGMYC).

Major epidemics, including some that qualify as pandemics, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), HIV, influenza A (H1N1)pdm/09 and most recently COVID-19, affect the lung. Tuberculosis (TB) remains the top infectious disease killer, but apart from syndemic TB/HIV little is known regarding the interaction of viral epidemics and pandemics with TB. The aim of this consensus-based document is to describe the effects of viral infections resulting in epidemics and pandemics that affect the lung (MERS, SARS, HIV, influenza A (H1N1)pdm/09 and COVID-19) and their interactions with TB. A search of the scientific literature was performed. A writing committee of international experts including the European Centre for Disease Prevention and Control Public Health Emergency (ECDC PHE) team, the World Association for Infectious Diseases and Immunological Disorders (WAidid), the Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Mycobacterial Infections (ESGMYC) was established. Consensus was achieved after multiple rounds of revisions between the writing committee and a larger expert group. A Delphi process involving the core group of authors (excluding the ECDC PHE team) identified the areas requiring review/consensus, followed by a second round to refine the definitive consensus elements. The epidemiology and immunology of these viral infections and their interactions with TB are discussed with implications for diagnosis, treatment and prevention of airborne infections (infection control, viral containment and workplace safety). This consensus document represents a rapid and comprehensive summary on what is known on the topic.

Is the EU model for contact investigation applicable to high TB burden settings?

Contact investigation is the search for secondary cases of tuberculosis (TB) or latent tuberculosis infection (LTBI) among contacts of patients with a transmissible form of TB, usually smear-positive pulmonary disease. The aim is to detect those who have already started developing TB in order to initiate treatment as soon as possible and prevent further transmission of the disease, and also to detect those who have been infected and could benefit from a preventive treatment before the development of TB. The implementation of preventive therapy for persons with the highest risk of developing TB, that is the reduction of the pool of future cases of TB, is now considered one of the activities able to support a decline in the prevalence of TB. This implies that the search for infected contacts and the prevention of TB should be performed in parallel with diagnostic and curative activities. The implementation of screening activities, at least for exposed children and immunocompromised persons, seems to be feasible without unaffordable costs, even in high TB burden settings.

Improvement in Tuberculosis Outcomes With a Combined Medical and Social Approach.

Setting: Studies performed locally in Switzerland in the late eighties reported unsatisfactory treatment outcomes. Better outcomes were observed since the introduction of directly observed therapy (DOT) in the late nineties and improvement in social support in recent years. Design: retrospective study of treatment outcomes for all tuberculosis (TB) patients notified in Vaud County (VD), Switzerland, between, 1st of January 2010 and 31st of December of 2014. Results: 375 patients were notified in VD during the study period. The global outcome was successful in 90.1% of patients (338/375). In 183 culture and PCR positive pulmonary TB, the documented cure rate was 57.9% (106/183), and the treatment completion was 59/183 (32.2%), i.e., a treatment success of 90.2%. DOT was applied globally in 234/375 (62.4%) and in 64/67 of the asylum seekers (AS) (95.5%) followed at the dispensary. Treatment outcomes were successful in 60/67 (89.6%) AS. Discussion: Improvements in tuberculosis outcomes resulted not only from the introduction of DOT in VD in the nineties but also from a change in the management, with increased attention to the social problems faced by the migrants. Conclusion: A combined medical and social approach of TB care in VD improved treatment outcomes.

Health-seeking behaviour and treatment delay in patients with pulmonary tuberculosis in Switzerland: some slip through the net.

AIMS OF THE STUDY: To assess the health-seeking behaviour, the patient delay (onset of symptoms to first consultation) and the health system delay (first consultation to start of tuberculosis treatment) among patients with pulmonary tuberculosis (TB) diagnosed in Switzerland, and to assess the predictors of the various types of delay. METHODS: A survey among pulmonary TB patients was carried out in six cantons, covering 42% of all pulmonary adult TB cases notified in Switzerland. Data were collected by collaborators of the cantonal lung associations in charge of the follow-up of TB patients to investigate treatment seeking behaviour and to establish various delays and its predictors. Predictors of percentiles of delay (median and 75th percentile) were assessed using quantile regression. RESULTS: Among 252 eligible patients, 162 patients could be interviewed. Of these, 20.4% were born in Switzerland. Cough as a symptom was mentioned by 76% of the interviewed patients. Almost half of the 162 patients (46%) consulted first a general practitioner in an ambulatory care setting and 26% approached a hospital first. The median delay between symptom onset and first healthcare contact (patient delay) was 5.2 weeks, which is slightly longer than findings in other low prevalence countries. The interquartile range was 1.6 to 14.2 weeks. The median delay between first consultation in Switzerland and the start of TB treatment (health system delay) was 2 weeks. The interquartile range was 0.6 to 7.1 weeks. There were no clear predictors of patient delay. The main predictors of a longer median health system delay were the presence of fever (1.6 weeks, 95% confidence interval [CI] 0.5 to 2.6 weeks), having visited first a general practitioner or a paediatrician (1 week, 95% CI 0.1 to 1.9 weeks) and having seen three or four doctors before beginning TB treatment (2.9 weeks, 95% CI 0.7 to 5.1 weeks). A clear predictor of a shorter median health system delay was having undergone an X-ray at the first consultation (-2.9 weeks, 95% CI -4.8 to -0.9 weeks). Marginally significant for shorter delay was male sex (-2.6 weeks, 95% CI -5.4 to 0.1 weeks). CONCLUSIONS: No predictor of patient delay was found among the variables collected. For one fourth of the patients, the health system delay was longer than 7 weeks. General practitioners are commonly approached first, and they have to consider TB, also for patients not considered at high-risk for TB.