Effectiveness of tuberculosis contact tracing among migrants and the foreign-born population

A literature review was performed to assess the effectiveness of tuberculosis (TB) contact tracing among migrants and the foreign-born population with emphasis on the European Union. Effectiveness of contact tracing was assessed using the following indicators: coverage, proportion of contacts with TB (TB yield), proportion of contacts with latent tuberculosis infection (LTBI yield) and number of investigated contacts per index case (contacts/index case ratio). The key findings from the literature review were: Among foreign-born contacts, a higher median LTBI yield was found compared with contacts born in the country, when exposed to the same foreign-born index cases. No clear differences were observed between TB and LTBI yield among contacts of foreign-born index cases compared with contacts of index cases from the general population (including the foreign-born) due to the large variation seen between the studies. The included non-European studies screened more contacts per foreign-born index case, used lower cut-off values to define a positive tuberculosis skin test and found higher LTBI yields among contacts. Although the high heterogeneity across the studies made the comparison challenging, several conclusions are made regarding contact tracing among migrants.