Active screening at entry for tuberculosis among new immigrants: a systematic review and meta-analysis

Evaluation of immigrant tuberculosis screening in industrialized countries

Improvements are needed in current screening, which is insufficient and ineffective.

In industrialized countries, tuberculosis (TB) cases are concentrated among immigrants and driven by reactivation of imported latent TB infection (LTBI). We examined mechanisms used to screen immigrants for TB and LTBI by sending an anonymous, 18-point questionnaire to 31 member countries of the Organisation for Economic Co-operation and Development. Twenty-nine (93.5%) of 31 responded; 25 (86.2%) screened immigrants for active TB. Fewer countries (16/29, 55.2%) screened for LTBI. Marked variations were observed in targeted populations for age (range <5 years of age to all age groups) and TB incidence in countries of origin of immigrants (>20 cases/100,000 population to >500 cases/100,000). LTBI screening was conducted in 11/16 countries by using the tuberculin skin test. Six countries used interferon-γ release assays, primarily to confirm positive tuberculin skin test results. Industrialized countries performed LTBI screening infrequently and policies varied widely. There is an urgent need to define the cost-effectiveness of LTBI screening strategies for immigrants.

Research questions and priorities for tuberculosis: a survey of published systematic reviews and meta-analyses

BACKGROUND

Systematic reviews are increasingly informing policies in tuberculosis (TB) care and control. They may also be a source of questions for future research. As part of the process of developing the International Roadmap for TB Research, we did a systematic review of published systematic reviews on TB, to identify research priorities that are most frequently suggested in reviews.

METHODOLOGY/PRINCIPAL FINDINGS

We searched EMBASE, MEDLINE, Web of Science, and the Cochrane Library for systematic reviews and meta-analyses on any aspect of TB published between 2005 and 2010. One reviewer extracted data and a second reviewer independently extracted data from a random subset of included studies. In total, 137 systematic reviews, with 141 research questions, were included in this review. We used the UK Health Research Classification System (HRCS) to help us classify the research questions and priorities. The three most common research topics were in the area of detection, screening and diagnosis of TB (32.6%), development and evaluation of treatments and therapeutic interventions (23.4%), and TB aetiology and risk factors (19.9%). The research priorities determined were mainly focused on the discovery and evaluation of bacteriological TB tests and drug-resistant TB tests and immunological tests. Other important topics of future research were genetic susceptibility linked to TB and disease determinants attributed to HIV/TB. Evaluation of drug treatments for TB, drug-resistant TB and HIV/TB were also frequently proposed research topics.

CONCLUSIONS

Systematic reviews are a good source of key research priorities. Findings from our survey have informed the development of the International Roadmap for TB Research by the TB Research Movement.

Community-based evaluation of immigrant tuberculosis screening using interferon γ release assays and tuberculin skin testing: observational study and economic analysis

BACKGROUND

UK tuberculosis (TB) notifications are rising due to disease in the immigrant population. National screening guidelines have been revised but cost-effectiveness analyses are hampered by the lack of data on the comparative performance of tuberculin skin tests (TSTs) and interferon γ release assays (IGRAs) in immigrants.

METHODS

Three-way evaluation of TSTs and two IGRAs (QuantiFERON Gold in-tube (QFN-GIT) and T-SPOT.TB) in immigrants aged ≥16 years to quantify test positivity, concordance and factors associated with positivity. Yields were computed at different incidence thresholds and the relative cost-effectiveness of screening was estimated using different latent TB infection (LTBI) screening modalities at varying incidence thresholds with or without port-of-arrival chest x-ray (CXR).

RESULTS

231 immigrants were included; median age 29 (IQR 24-37). TSTs were accepted by 80.9%, read in 93.5% and 30.3% were positive - QFN-GIT and T-SPOT.TB positive in 16.6% and 22.5% respectively. Positive TSTs, QFN-GIT and T-SPOT.TB were independently associated with increasing TB incidence in immigrants' countries of origin (p=0.007, 0.007, 0.037 respectively). Implementing current guidance (threshold 40/100 000 per year) would identify 98-100% of LTBIs (depending on test) but entail testing 97-99% of the cohort; screening at 150/100 000 per year would identify 49-71% of LTBIs but only entail screening half the cohort. The two most cost-effective screening strategies were no port-of-entry chest radiography and screen with single-step QFN-GIT at 250/100 000 per year (incremental cost-effectiveness ratio (ICER)) £21 565.3/case averted); and no port-of-entry CXR and screen with single-step QFN-GIT at 150/100 000 per year (averted additional 7.8 TB cases; ICER £31 867.1/case averted).

CONCLUSIONS

UK immigrant screening could cost-effectively and safely eliminate mandatory CXR on arrival by emphasising systematic screening for LTBI with single-step IGRA. Intermediate incidence thresholds balance the need to identify as many imported LTBIs as possible against limited service capacity.

European union standards for tuberculosis care

The European Centre for Disease Prevention and Control (ECDC) and the European Respiratory Society (ERS) jointly developed European Union Standards for Tuberculosis Care (ESTC) aimed at providing European Union (EU)-tailored standards for the diagnosis, treatment and prevention of tuberculosis (TB). The International Standards for TB Care (ISTC) were developed in the global context and are not always adapted to the EU setting and practices. The majority of EU countries have the resources and capacity to implement higher standards to further secure quality TB diagnosis, treatment and prevention. On this basis, the ESTC were developed as standards specifically tailored to the EU setting. A panel of 30 international experts, led by a writing group and the ERS and ECDC, identified and developed the 21 ESTC in the areas of diagnosis, treatment, HIV and comorbid conditions, and public health and prevention. The ISTCs formed the basis for the 21 standards, upon which additional EU adaptations and supplements were developed. These patient-centred standards are targeted to clinicians and public health workers, providing an easy-to-use resource, guiding through all required activities to ensure optimal diagnosis, treatment and prevention of TB. These will support EU health programmes to identify and develop optimal procedures for TB care, control and elimination.

Blind spots and adverse conditions of care: screening migrants for tuberculosis in France and Germany

Tuberculosis (TB) is an infectious disease that declined significantly throughout the 20(th) century. Large-scale TB screening of entire populations in France and Germany has thus been replaced by active screening of risk-groups, particularly migrants. The article engages with its problems and practices on three levels: by looking at the way information on migrants as an at-risk group is produced through disease surveillance data; by analysing how such at-risk group data influence local screening practices; and by showing which political and medical problems arise in the field. I overturn the discussion about screening and surveillance of migrants as a risk-group by showing that it is not the stigmatisation of migrants through disease risk that is most at stake, but the invisibility of the most vulnerable among them in disease surveillance data and the way restrictive national immigration policies interfere with and subvert local screening and treatment practices targeting them. The aim of my article is to promote a pragmatic sociology of screening, while paying attention to the practical complexities, political conditions and medical ambivalences of screening and follow-up care, especially when the migrant groups concerned are socially, politically and medically vulnerable.

Enhancing the management of cross-regional transfer of floating tuberculosis cases by active follow-up and communication

OBJECTIVES

To analyse the effects of an intervention on cross-regional transfer of tuberculosis (TB) patients among floating population.

METHODS

On 1 October 2008, the 1-year intervention started by strengthening patients' health education, supervising medical treatments at critical phases, assisting in the transference of TB patients and persisting communication with TB dispensaries outside Shenzhen city. Data were collected from the TB patients' registry book and the TB transference and follow-ups recording book. Primary outcomes were compared at the pre-intervention (From 1 October 2007 to 30 September 2008) and intervention periods.

RESULTS

A total of 1131 floating tuberculosis cases were registered (594 at the intervention period). Compared with those at the pre-intervention period, the rate of patients' informing doctors before leaving Shenzhen increased significantly (61.8% vs. 39.4%), the rate of successful transference mildly improved (60.0% vs. 50.0%), while the rate decreased dramatically for the re-registered patients at TB dispensaries outside Shenzhen (51.5% vs. 93.6%).

CONCLUSION

The intervention improves patients' adherence and enhances collaboration between TB dispensaries, establishes more practical mechanisms, which could be useful for TB control in China. However, more efforts should be directed towards improvement of TB control among floating population, especially advocating the economic perspective.

Health aspects of the pre-departure phase of migration

In the second article in a six-part PLoS Medicine series on Migration & Health, Brian Gushulak and Douglas MacPherson discuss the pre-departure phase of migration and the specific health risks and policy needs associated with this phase.

Tuberculosis incidence in prisons: a systematic review

BACKGROUND

Transmission of tuberculosis (TB) in prisons has been reported worldwide to be much higher than that reported for the corresponding general population.

METHODS AND FINDINGS

A systematic review has been performed to assess the risk of incident latent tuberculosis infection (LTBI) and TB disease in prisons, as compared to the incidence in the corresponding local general population, and to estimate the fraction of TB in the general population attributable (PAF%) to transmission within prisons. Primary peer-reviewed studies have been searched to assess the incidence of LTBI and/or TB within prisons published until June 2010; both inmates and prison staff were considered. Studies, which were independently screened by two reviewers, were eligible for inclusion if they reported the incidence of LTBI and TB disease in prisons. Available data were collected from 23 studies out of 582 potentially relevant unique citations. Five studies from the US and one from Brazil were available to assess the incidence of LTBI in prisons, while 19 studies were available to assess the incidence of TB. The median estimated annual incidence rate ratio (IRR) for LTBI and TB were 26.4 (interquartile range [IQR]: 13.0-61.8) and 23.0 (IQR: 11.7-36.1), respectively. The median estimated fraction (PAF%) of tuberculosis in the general population attributable to the exposure in prisons for TB was 8.5% (IQR: 1.9%-17.9%) and 6.3% (IQR: 2.7%-17.2%) in high- and middle/low-income countries, respectively.

CONCLUSIONS

The very high IRR and the substantial population attributable fraction show that much better TB control in prisons could potentially protect prisoners and staff from within-prison spread of TB and would significantly reduce the national burden of TB. Future studies should measure the impact of the conditions in prisons on TB transmission and assess the population attributable risk of prison-to-community spread. Please see later in the article for the Editors' Summary.