Targeting screening and treatment for latent tuberculosis infection towards asylum seekers from high-incidence countries - a model-based cost-effectiveness analysis

Screening for latent tuberculosis in migrants-status quo and future challenges

OBJECTIVES

To review the evidence that migrants from tuberculosis (TB) high-incidence countries migrating to TB low-incidence countries significantly contribute to active TB cases in the counties of destination, primarily through reactivation of latent TB.

METHODS

This is a narrative review. The different screening programs in the countries of destination are reviewed either based on screening and preventive treatment of latent TB pre or more commonly - post arrival.

RESULTS

Screening can be performed using interferon-gamma release assays (IGRA) or tuberculin skin tests (TST). Preventive treatment of latent TB is using either monotherapy with isoniazid, or in combination with rifampicin or rifapentine. We discuss the ethical issues of preventive treatment in asymptomatic individuals and how these are addressed in different screening programs.

CONCLUSION

Screening migrants from TB high endemic countries to TB low endemic countries is beneficial. There is a lack of standardization and agreement on screening protocols, follow up and treatment.

Screening for Tuberculosis Infection among Migrants: A Cost-Effectiveness Analysis in the Italian Context

BACKGROUND

Screening of tuberculosis infection (TBI) among migrants from high-incidence countries is a cornerstone of tuberculosis control in low-incidence countries. However, the optimal screening strategy has not been defined yet.

METHODS

A quasi-experimental study involving migrants residing in the province of Brescia was carried out that aimed at assessing the completion rate, time to completion, preventive treatment initiation rate, and cost-effectiveness of two strategies for TBI screening. They underwent TBI screening with the IGRA-only strategy (arm 1) or with the sequential strategy (tuberculin skin test, TST, followed by IGRA in case of a positive result-arm 2). The two strategies were compared in terms of screening completion, time to complete the screening process, therapy initiation, and cost-effectiveness.

RESULTS

Between May 2019 and May 2022, 657 migrants were evaluated, and 599 subjects were included in the study, with 358 assigned to arm 1 and 237 to arm 2. Screening strategy was the only factor associated with screening completion in a multivariable analysis, with the subjects assigned to the IGRA-only strategy more likely to complete the screening cascade (n = 328, 91.6% vs. n = 202, 85.2%, IRR 1.08, 95% CI (1.01-1.14), p = 0.019). The time to complete the screening process was significantly longer for patients assigned to the sequential strategy arm (74 days vs. 46 days, p = 0.002). Therapy initiation did not significantly differ between the two arms, and cost-effectiveness was higher for the sequential strategy.

CONCLUSION

Sequential strategy implementation for TBI screening among migrants may be justified by its higher cost-effectiveness in spite of the lower completion of the screening cascade.

The Global Expansion of LTBI Screening and Treatment Programs: Exploring Gaps in the Supporting Economic Evidence

The global burden of latent TB infection (LTBI) and the progression of LTBI to active TB disease are important drivers of ongoing TB incidence. Addressing LTBI through screening and TB preventive treatment (TPT) is critical in order to end the TB epidemic by 2035. Given the limited resources available to health ministries around the world in the fight against TB, we must consider economic evidence for LTBI screening and treatment strategies to ensure that limited resources are used to achieve the biggest health impact. In this narrative review, we explore key economic evidence around LTBI screening and TPT strategies in different populations to summarize our current understanding and highlight gaps in existing knowledge. When considering economic evidence supporting LTBI screening or evaluating different testing approaches, a disproportionate number of economic studies have been conducted in high-income countries (HICs), despite the vast majority of TB burden being borne in low- and middle-income countries (LMICs). Recent years have seen a temporal shift, with increasing data from low- and middle-income countries (LMICs), particularly with regard to targeting high-risk groups for TB prevention. While LTBI screening and prevention programs can come with extensive costs, targeting LTBI screening among high-risk populations, such as people living with HIV (PLHIV), children, household contacts (HHC) and immigrants from high-TB-burden countries, has been shown to consistently improve the cost effectiveness of screening programs. Further, the cost effectiveness of different LTBI screening algorithms and diagnostic approaches varies widely across settings, leading to different national TB screening policies. Novel shortened regimens for TPT have also consistently been shown to be cost effective across a range of settings. These economic evaluations highlight key implementation considerations such as the critical nature of ensuring high rates of adherence and completion, despite the costs associated with adherence programs not being routinely assessed and included. Digital and other adherence support approaches are now being assessed for their utility and cost effectiveness in conjunction with novel shortened TPT regimens, but more economic evidence is needed to understand the potential cost savings, particularly in settings where directly observed preventive therapy (DOPT) is routinely conducted. Despite the growth of the economic evidence base for LTBI screening and TPT recently, there are still significant gaps in the economic evidence around the scale-up and implementation of expanded LTBI screening and treatment programs, particularly among traditionally hard-to-reach populations.

Impact of COVID-19 Pandemic on Tuberculosis Preventive Services and Their Post-Pandemic Recovery Strategies: A Rapid Review of Literature

BACKGROUND

Coronavirus disease 2019 (COVID-19) pandemic has disrupted tuberculosis (TB) care and prevention around the world. The aim of this study is to review literature on the impact of COVID-19 on TB preventive services and discuss their policy options during and after the pandemic.

METHODS

We conducted a rapid review of scientific literature on the impact of COVID-19 on TB preventive services and their recovery strategies. After conducting a line-by-line open coding, their codes were applied in the descriptive theme building process, which was guided by the End TB strategy. TB preventive measures were selected and classified into five analytical categories: 1) vaccination against TB, 2) detection and treatment of latent TB infection (LTBI), 3) screening and diagnostics, 4) active case finding and contact tracing, and 5) surveillance.

RESULTS

We identified 93 articles, of which 65 were research articles. During the pandemic, we observed decrease in Bacillus Calmette-Guérin (BCG) coverage, TB diagnostic services, case finding activities, and LTBI management. TB case detection was declined, which was not resumed to the pre-pandemic level after loosening the lock-down. Several recommendations were highlighted: 1) secure BCG stocks and its supply chains, 2) consider catch-up activities of routine immunization and LTBI screening, 3) maintain minimal TB health services, infection prevention and control, and surveillance, 4) leverage laboratory capacity and contact tracing mechanisms, 5) consider simultaneous testing for TB and COVID-19, and 6) Incorporate digital health technologies.

CONCLUSIONS

Our findings and lessons learnt from the pandemic can aid in the development of future national TB control program.

Mandatory, voluntary, repetitive, or one-off post-migration follow-up for tuberculosis prevention and control: A systematic review

BACKGROUND

Post-migration follow-up of migrants identified to be at-risk of developing tuberculosis during the initial screening is effective, but programmes vary across countries. We aimed to review main strategies applied to design follow-up programmes and analyse the effect of key programme characteristics on reported coverage (i.e., proportion of migrants screened among those eligible for screening) or yields (i.e., proportion of active tuberculosis among those identified as eligible for follow-up screening).

METHODS AND FINDINGS

We performed a systematic review and meta-analysis of studies reporting yields of follow-up screening programmes. Studies were included if they reported the rate of tuberculosis disease detected in international migrants through active case finding strategies and applied a post-migration follow-up (defined as one or more additional rounds of screening after finalising the initial round). For this, we retrieved all studies identified by Chan and colleagues for their systematic review (in their search until January 12, 2017) and included those reporting from active follow-up programmes. We then updated the search (from January 12, 2017 to September 30, 2022) using Medline and Embase via Ovid. Data were extracted on reported coverage, yields, and key programme characteristics, including eligible population, mode of screening, time intervals for screening, programme providers, and legal frameworks. Differences in follow-up programmes were tabulated and synthesised narratively. Meta-analyses in random effect models and exploratory analysis of subgroups showed high heterogeneity (I2 statistic > 95.0%). We hence refrained from pooling, and estimated yields and coverage with corresponding 95% confidence intervals (CIs), stratified by country, legal character (mandatory versus voluntary screening), and follow-up scheme (one-off versus repetitive screening) using forest plots for comparison and synthesis. Of 1,170 articles, 24 reports on screening programmes from 7 countries were included, with considerable variation in eligible populations, time intervals of screening, and diagnostic protocols. Coverage varied, but was higher than 60% in 15 studies, and tended to be lower in voluntary compared to compulsory programmes, and higher in studies from the United States of America, Israel, and Australia. Yield varied within and between countries and ranged between 53.05 (31.94 to 82.84) in a Dutch study and 5,927.05 (4,248.29 to 8,013.71) in a study from the United States. Of 15 estimates with narrow 95% CIs for yields, 12 were below 1,500 cases per 100,000 eligible migrants. Estimates of yields in one-off follow-up programmes tended to be higher and were surrounded by less uncertainty, compared to those in repetitive follow-up programmes. Yields in voluntary and mandatory programmes were comparable in magnitude and uncertainty. The study is limited by the heterogeneity in the design of the identified screening programmes as effectiveness, coverage and yields also depend on factors often underreported or not known, such as baseline incidence in the respective population, reactivation rate, educative and administrative processes, and consequences of not complying with obligatory measures.

CONCLUSION

Programme characteristics of post-migration follow-up screening for prevention and control of tuberculosis as well as coverage and yield vary considerably. Voluntary programmes appear to have similar yields compared with mandatory programmes and repetitive screening apparently did not lead to higher yields compared with one-off screening. Screening strategies should consider marginal costs for each additional round of screening.

Densitometric substantiation of the application regimes in a low-temperature electric welding of soft living tissues in phthisiosurgery

Objective. To determine the optimal regimes of application of a low-temperature electric welding of soft living tissues in formation of suture in pulmonary parenchyma, the pulmonary hilum preparation, and its lymph nodes ablation, basing on microbiological estimation of action of various regimes on the tuberculosis mycobacteria and densitometric indices of pulmonary parenchyma and to estimate its efficacy in far remote postoperative period. Materials and methods. The work is based on the results of postoperative investigations in 275 patients with the aim to determine the impact of a low-temperature electric welding of soft living tissues on pulmonary parenchyma and mediastinal lymph nodes. Results. There was established, that application of minimal automatic regime of a low-temperature electric welding of soft living tissues in phthisiosurgery guarantees effective elimination of microflora in 98.3% of patients. The revealed emphysematous processes and fibrous changes are occurring in parallel and essentially impacts the development of pulmonary-pleural complications. Conventional density of pulmonary parenchyma was noted in 57.5% of patients in the investigation group and in 49.7% patients of the control group. In both groups, the enhanced superdensity of pulmonary parenchyma in far remote postoperative period was not observed. Density of mediastinal lymph nodes was compared, and statistically significant difference between densitometric indices of mediastinal lymph nodes was absent. While application of a low-temperature electric welding of soft living tissues in minimal power regime of the complex there was noted essential characteristic as well: lesser rate of fibrous transformation of pulmonary parenchyma, than in the control group –  in 13.3 and 15.5%, accordingly. Conclusion. Application of a low-temperature electric welding of soft living tissues in phthisiosurgical interventions for the lymph nodes ablation have shown the presence of effective bactericidal regimes with preservation of lymphatic circulation, and low rigidity of pulmonary parenchyma in postoperative period. While a low-temperature electric welding of soft living tissues applied, the signs of lymphostasis, the lymphatic outflow disorders and pulmonary-pleural complications in postoperative period after phthisiosurgical interventions with the lymph node ablation procedure do not occur, as well as the risk of iatrogenic damages while performing dissection and excision of mediastinal lymph nodes.

The cascade of care in tuberculosis infection screening and management in newly arrived refugees in Aarhus, Denmark

BACKGROUND

Screening for tuberculosis (TB) disease and infection is often a part of health screening programs offered to refugees, but the yield of screening varies and losses along the steps from screening to treatment completion was reported.

METHODS

A retrospective cohort study was performed investigating a newly arrived refugee population offered a systematic refugee health assessment in Aarhus, Denmark. Data was collected on screening, referral, diagnosis and treatment for TB disease and infection.

RESULTS

Among both adults and children IGRA positivity was associated with origin in a high TB incidence country and increasing age. The number needed to screen (NNS) to find one case of TB infection was 7 among adult refugees and 19 among children, while NNS for TB disease was 266 and 164 respectively. The proportion of the eligible population with a valid result was 78.1% for adults and 71.3% for children, while 43.1% and 50% of adults and children with presumed TB infection completed preventive treatment.

DISCUSSION

Screening for TB disease and infection among refugees in Aarhus had a high yield in terms of diagnosis, however significant losses were seen during screening, follow-up and preventive treatment completion.