Demographics of tuberculosis in an emerging EU region in Southern Scandinavia

"It is more than the issue of taking tablets": the interplay between migration policies and TB control in Sweden

OBJECTIVES

Tuberculosis is re-emerging as a critical public health concern in Sweden among the immigrants. The aim of this study was to explore the experiences of the Somali community of TB care in the Stockholm area.

METHODS

Focus group discussions were conducted with 34 adult women and men by a Somali speaking moderator. Each group consisted of 6-9 participants-men and women separately. The audio taped discussions were transcribed, translated and read many times and in the process patterns and codes were identified and migration emerged as important theme in the context of TB control.

RESULTS

Fear of being deported emerged as barrier to sharing of complete health information with the doctor. The routine contact tracing and follow-up of infected cases in TB control was expressed as a source of concern since it was feared the health care providers could share the information with the immigration authorities. Interpreter use was expressed as barrier particularly if of same female gender.

CONCLUSION

It is important to be aware of how a country's immigration policies impact on TB control activities among immigrants The existing TB control measures, such as contact tracing, assume new meanings for immigrants. Further research is therefore needed to understand this emerging complexity in order to make TB control more effective.

Use of a T cell interferon gamma release assay in the investigation for suspected active tuberculosis in a low prevalence area

Background

In settings with low background prevalence of tuberculosis (TB) infection, interferon-γ release assays (IGRA) could be useful for diagnosing active TB. This study aims to evaluate the performance of QuantiFERON^®-TB Gold (QFT-G) in the investigation for suspected active TB, with particular attention to patients originating in high-incidence countries. Furthermore, factors associated with QFT-G results in patients with active TB were assessed.

Methods

From patients investigated for clinically suspected active TB, blood was obtained for QFT-G testing, in addition to routine investigations. Positive (PPV) and negative (NPV) predictive values for QFT-G were calculated, comparing patients with confirmed TB and those with other final diagnoses. QFT-G results in TB patients originating from countries with intermediate or high TB incidence were compared with QFT-G results from a control group of recently arrived asymptomatic immigrants from high-incidence countries. Factors associated with QFT-G outcome in patients with confirmed TB were assessed.

Results

Among 141 patients, 41/70 (58.6%) with confirmed TB had a positive QFT-G test, compared to 16/71 (22.6%) patients with other final diagnoses, resulting in overall PPV of 71.9% and NPV of 67.6%. For patients with pulmonary disease, PPV and NPV were 61.1% and 67.7%, respectively, and 90.5% and 66.7% for subjects with extrapulmonary manifestations. Comparing patients from high-incidence countries with controls yielded a PPV for active TB of 76.7%, and a NPV of 82.7%. Patients with confirmed TB and positive QFT-G results were characterized by a lower median peripheral white blood cell count (5.9 × 10⁹/L vs. 8.8 × 10⁹/L; P < 0.001) and a higher median body mass index (22.7 vs. 20.7; P = 0.043) as compared to QFT-G-negative TB patients.

Conclusion

The overall PPV and NPV of QFT-G for identifying active TB were unsatisfactory, especially for pulmonary disease. Thus, the usefulness of QFT-G for this purpose is questionable. However, a high PPV was observed for extrapulmonary TB and QFT-G might be considered in the diagnostic process in this situation. The PPV and NPV for identifying active TB among persons originating from regions with high-and intermediate TB incidence was similar to that observed in subjects originating in the low-incidence region.

BCG scar and tuberculin reactivity in children and adults

Bacille Calmette-Guérin (BCG) vaccination generally leads to scar formation and tuberculin skin test (TST) reactivity. This study aimed at analysing these 2 parameters and their correlation in a setting with a low prevalence of tuberculosis. Retrospectively, we analysed 314 children and 390 adults living in Sweden and known from records or individual recall to have undergone BCG vaccination. A BCG scar was present in 161 (51%) of the children and in 340 (87%) of the adults. Among children with a scar, 94 (58%) were TST-positive (>or=6 mm) compared to 23 (15%) of 154 children lacking a visible scar. Among adults with a scar, 258 (76%) were TST- positive compared to 23 (46%) of 50 with no scar. Out of 152 non-vaccinated adults, 142 (94.4%) were TST-negative. When 175 TST-negative health care students were BCG-vaccinated in a prospective part of the study, 174 (99%) were found to develop a scar. In essence, the study showed a positive correlation between scar presence and TST reactivity. Furthermore, BCG vaccination of adults in the present setting resulted in consistent scar formation, while scar prevalence in previously vaccinated children was low.