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.

1.
Baussano
I
,
Nunn
P
,
Williams
B
,
Pivetta
E
,
Bugiani
M
,
Scano
F
.
Tuberculosis among health care workers
.
Emerg Infect Dis
.
2011 Mar
;
17
(
3
):
488
94
. .
2.
Uden
L
,
Barber
E
,
Ford
N
,
Cooke
GS
.
Risk of tuberculosis infection and disease for health care workers: an updated meta-analysis
.
Open Forum Infect Dis
.
2017 Summer
;
4
(
3
):
ofx137
. .
3.
Furin
J
,
Sotgiu
G
.
Protecting those who serve: are we doing enough to prevent tuberculosis in healthcare workers?
Eur Respir J
.
2019 Apr
;
53
(
4
):
1900485
. .
4.
Youakim
S
.
The occupational risk of tuberculosis in a low-prevalence population
.
Occup Med
.
2016 Aug
;
66
(
6
):
466
70
. .
5.
Grenzel
ML
,
Grande
AJ
,
Paniago
AMM
,
Pompilio
MA
,
de Oliveira
SMVL
,
Trajman
A
.
Tuberculosis among correctional facility workers: a systematic review and meta-analysis
.
PLoS One
.
2018
;
13
(
11
):
e0207400
. .
6.
World Health Organization
.
Guidelines on the management of latent tuberculosis infection
.
WHO
;
2015
.
7.
Swiss Federal Council
.
Regulation on the prevention of accidents and occupational diseases
.
Berne
:
Swiss Federal Council
;
1983
.
8.
Swiss Federal Council
.
Regulation on the protection of workers from the risks related to micro-organisms
.
Berne
:
Swiss Federal Council
;
1999
.
9.
Jost
M
,
Merz
B
,
Ruegger
M
,
Zellweger
JP
,
Shang Meier
H
,
Cartier
B
, et al
Tuberkulose am Arbeitsplatz, Gefährdung und Prävention
.
Lucerne
;
2010
.
10.
Pai
M
,
Denkinger
CM
,
Kik
SV
,
Rangaka
MX
,
Zwerling
A
,
Oxlade
O
, et al
Gamma interferon release assays for detection of Mycobacterium tuberculosis infection
.
Clin Microbiol Rev
.
2014 Jan
;
27
(
1
):
3
20
. .
11.
Slater
ML
,
Welland
G
,
Pai
M
,
Parsonnet
J
,
Banaei
N
.
Challenges with QuantiFERON-TB gold assay for large-scale, routine screening of U.S. healthcare workers
.
Am J Respir Crit Care Med
.
2013 Oct 15
;
188
(
8
):
1005
10
. .
12.
Dorman
SE
,
Belknap
R
,
Graviss
EA
,
Reves
R
,
Schluger
N
,
Weinfurter
P
, et al
Interferon-γ release assays and tuberculin skin testing for diagnosis of latent tuberculosis infection in healthcare workers in the United States
.
Am J Respir Crit Care Med
.
2014 Jan 1
;
189
(
1
):
77
87
. .
13.
Sepkowitz
KA
.
Tuberculosis and the health care worker: a historical perspective
.
Ann Intern Med
.
1994
;
120
(
1
):
71
9
. .
14.
Durando
P
,
Sotgiu
G
,
Spigno
F
,
Piccinini
M
,
Mazzarello
G
,
Viscoli
C
, et al
Latent tuberculosis infection and associated risk factors among undergraduate healthcare students in Italy: a cross-sectional study
.
BMC Infect Dis
.
2013
;
13
:
443
. .
15.
Schablon
A
,
Beckmann
G
,
Harling
M
,
Diel
R
,
Nienhaus
A
.
Prevalence of latent tuberculosis infection among health care workers in a hospital for pulmonary diseases
.
J Occup Med Toxicol
.
2009 Jan 9
;
4
:
1
. .
16.
Nardell
EA
.
Indoor environmental control of tuberculosis and other airborne infections
.
Indoor Air
.
2016 Feb
;
26
(
1
):
79
87
. .
17.
Rudaz
L
,
Rime-Dubey
B
,
Zellweger
JP
.
Risk of tuberculous infection among health-care workers in two hospitals with different patient populations in Lausanne, Switzerland
.
Tubercle Lung Dis
.
1996
;
77
(
2
):
109
.
18.
Hinks
TS
,
Varsani
N
,
Godsiff
DT
,
Bull
TC
,
Nash
KL
,
McLuckie
L
, et al
High background rates of positive tuberculosis-specific interferon-gamma release assays in a low prevalence region of UK: a surveillance study
.
BMC Infect Dis
.
2012
;
12
:
339
.
19.
Mancuso
JD
,
Diffenderfer
JM
,
Ghassemieh
BJ
,
Horne
DJ
,
Kao
TC
.
The prevalence of latent tuberculosis infection in the United States
.
Am J Respir Crit Care Med
.
2016 Aug 15
;
194
(
4
):
501
9
. .
20.
Cohen
A
,
Mathiasen
VD
,
Schön
T
,
Wejse
C
.
The global prevalence of latent tuberculosis: a systematic review and meta-analysis
.
Eur Respir J
.
2019 Sep
;
54
(
3
). .
21.
Schablon
A
,
Harling
M
,
Diel
R
,
Ringshausen
FC
,
Torres Costa
J
,
Nienhaus
A
.
Serial testing with an interferon-γ release assay in German healthcare workers
.
GMS Krankenhhyg Interdiszip
.
2010
;
5
(
2
):
Doc05
. .
22.
Dobler
CC
,
Farah
WH
,
Alsawas
M
,
Mohammed
K
,
Breeher
LE
,
Murad
MH
, et al
Tuberculin skin test conversions and occupational exposure risk in US healthcare workers
.
Clin Infect Dis
.
2018 Feb 10
;
66
(
5
):
706
11
. .
23.
Schablon
A
,
Peters
C
,
Diel
R
,
Diner
G
,
Anske
U
,
Pankow
W
, et al
Serial IGRA testing of trainees in the healthcare sector in a country with low incidence for tuberculosis: a prospective cohort study
.
GMS Hyg Infect Control
.
2013
;
8
(
2
):
Doc17
. .
24.
Mullie
GA
,
Schwartzman
K
,
Zwerling
A
,
N‘Diaye
DS
.
Revisiting annual screening for latent tuberculosis infection in healthcare workers: a cost-effectiveness analysis
.
BMC Med
.
2017 May 17
;
15
(
1
):
104
. .
25.
Federal Office of Public Health and Swiss Lung Association
.
Tuberculosis in Switzerland. Guidance for healthcare professionals
.
Berne
:
Swiss Lung Association
;
2014
.
26.
Sosa
LE
,
Njie
GJ
,
Lobato
MN
,
Bamrah Morris
S
,
Buchta
W
,
Casey
ML
, et al
Tuberculosis screening, testing, and treatment of U.S. health care personnel: recommendations from the National Tuberculosis Controllers Association and CDC, 2019
.
Morb Mortal Wkly Rep
.
2019 May 17
;
68
(
19
):
439
43
. .
27.
Winje
BA
,
White
R
,
Syre
H
,
Skutlaberg
DH
,
Oftung
F
,
Mengshoel
AT
, et al
Stratification by interferon-gamma release assay level predicts risk of incident TB
.
Thorax
.
2018 Apr 5
;
73
.
28.
Acuna-Villaorduna
C
,
Jones-Lopez
EC
,
Fregona
G
,
Marques-Rodrigues
P
,
Gaeddert
M
,
Geadas
C
, et al
Intensity of exposure to pulmonary tuberculosis determines risk of tuberculosis infection and disease
.
Eur Respir J
.
2018 Jan
;
51
(
1
):
1701578
.
29.
Duarte
R
,
Lönnroth
K
,
Carvalho
C
,
Lima
F
,
Carvalho
ACC
,
Muñoz-Torrico
M
, et al
Tuberculosis, social determinants and co-morbidities (including HIV)
.
Pulmonology
.
2018 Mar–Apr
;
24
(
2
):
115
9
. .
30.
Nemes
E
,
Rozot
V
,
Geldenhuys
H
,
Bilek
N
,
Mabwe
S
,
Abrahams
D
, et al
Optimization and interpretation of serial QuantiFERON testing to measure acquisition of Mycobacterium tuberculosis infection
.
Am J Respir Crit Care Med
.
2017 Sep 1
;
196
(
5
):
638
48
. .
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