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Open Access Highly Accessed Research article

Factors associated with latent tuberculosis among asylum seekers in Switzerland: a cross-sectional study in Vaud County

Apostolos Sarivalasis1*, Jean-Pierre Zellweger2, Mohamed Faouzi3, Oscar Daher4, Charlotte Deslarzes5 and Patrick Bodenmann1

Author Affiliations

1 Department of Ambulatory Care and Community Medicine (PMU), Rue du Bugnon 44, 1011, Lausanne, Vaud, Switzerland

2 Swiss Lung Association, Vaud section (LPVD), Av de Provence 4, 1007, Lausanne, Vaud, Switzerland

3 Institute of Social and Preventive Medicine (IUMSP), Rue du Bugnon 44, 1011, Lausanne, Vaud, Switzerland

4 Health Center – Sainte-Croix Hospital (CSSC), Rue des Rosiers 29,1450 Ste-Croix, Vaud, Switzerland

5 Nurse, Health Center (CSI), Rue du Bugnon 44, 1011, Lausanne, Vaud, Switzerland

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BMC Infectious Diseases 2012, 12:285  doi:10.1186/1471-2334-12-285

Published: 2 November 2012

Abstract

Background

Screening and treatment of latent tuberculosis infection (LTBI) in asylum seekers (AS) may prevent future cases of tuberculosis. As the screening with Interferon Gamma Release Assay (IGRA) is costly, the objective of this study was to assess which factors were associated with LTBI and to define a score allowing the selection of AS with the highest risk of LTBI.

Methods

In across-sectional study, AS seekers recently arrived in Vaud County, after screening for tuberculosis at the border were offered screening for LTBI with T-SPOT.TB and questionnaire on potentially risk factors. The factors associated with LTBI were analyzed by univariate and multivariate regression.

Results

Among 393 adult AS, 98 (24.93%) had a positive IGRA response, five of them with active tuberculosis previously undetected. Six factors associated with LTBI were identified in multivariate analysis: origin, travel conditions, marital status, cough, age and prior TB exposure. Their combination leads to a robust LTBI predictive score.

Conclusions

The prevalence of LTBI and active tuberculosis in AS is high. A predictive score integrating six factors could identify the asylum seekers with the highest risk for LTBI.

Keywords:
Asylum seeker; Latent tuberculosis infection; Tuberculosis; Risk factors; Predictive score; Interferon gamma release assay