Latent tuberculous infection among foreign-born individuals applying to shelters in the metropolitan area of Milan.

Abstract

Screening for latent tuberculous infection (LTBI) of groups at high risk of active tuberculosis (TB) is a key component of the End TB Strategy. To conduct a retrospective descriptive analysis of LTBI rates among foreign-born individuals applying to shelters in the metropolitan area of Milan, Italy. All foreign-born individuals registering for accommodation centres in the city of Milan from November 2009 to April 2017 were screened for active TB and LTBI. Individuals aged <36 years with a tuberculin skin test (TST) induration of >10 mm were offered confirmatory testing with QuantiFERON®-TB Gold In-Tube (QFT-GIT). Of the 2666 TST-positive migrants aged <36 years who underwent LTBI confirmation testing, 1322 (49.6%) tested negative, 1339 (50.2%) were positive and five (0.2%) had indeterminate results. In the multivariate analysis, TB incidence in the country of origin and age were significantly associated with QFT-GIT positivity. Although estimated TB incidence in Eritrea, Morocco and Romania was 100/100 000 person-years (py), the probability of being QFT-GIT-positive in individuals from these countries were not statistically significantly different from individuals from countries with TB incidence > 250/100 000 person-years. Our data showed a high proportion of LTBI among individuals coming from intermediate TB burden countries.