The identification and treatment of latent tuberculosis infection (LTBI) among immigrants from high-incidence regions who move to low-incidence countries is generally considered an ineffective strategy because only ≈14% of them comply with the multiple steps of the ‘cascade of care’ and complete treatment. In the Estrie region of Canada, a refugee clinic was opened in 2009. One of its goals is LTBI management. Between 2009-2020, 5131 refugees were evaluated. To determine the efficacy and benefit-cost ratio of this intervention, records of refugees seen in 2010-14 (n=1906) and 2018-19 (n=1638) were reviewed. Cases of tuberculosis (TB) among our foreign-born population occurring before (1997-2008) and after (2009-2020) setting up the clinic were identified. All costs associated with TB or LTBI were measured. Out of 441 patients offered LTBI treatment, 374 (85%) were compliant. Adding other losses, overall compliance was 69%. To prevent one case of TB, 95.1 individuals had to be screened and 11.9 treated, at a cost of $16,056. After discounting, each case of TB averted represented $32,631, for a benefit-cost ratio of 2.03. Among nationals of the 20 countries where refugees came from, incidence of TB decreased from 68.2 (1997-2008) to 26.3 per 100,000 person-years (2009-2020). Incidence among persons from high-incidence countries not targeted by the intervention did not change (12.4 vs 12.8 per 100,000) Among refugees settling in our region, 69% completed the LTBI cascade of care, leading to a 61% reduction in TB incidence. This intervention was cost-beneficial. Key factors for this satisfactory compliance included: close collaboration with community organizations, its integration within a comprehensive package of medical care for the whole family, its delivery shortly after arrival, shorter rifampicin-based treatment, and risk-based selection of patients to be treated. Management of LTBI among migrants should not be considered a lost cause.

Statistics Canada provided data concerning the country of birth of all individuals living in Estrie region from censuses or surveys performed in 1996, 2001, 2006, 2011 and 2016. Foreign-born individuals include immigrants, non-permanent residents (students, qualified workers) and respondents born abroad of Canadian parents. Intercensal estimates were calculated according to the rate of change between censuses for specific subpopulations. Immigration Canada provided data on the number and categories of immigrants, for each country, who settled in Estrie from 2009 to 2020. Cases of TB were idenfied through our hospital records and defined defined as patients having Mycobacterium tuberculosis detected by culture and/or polymerase chain reaction. The annual incidence of tuberculosis in the immigrants' home countries for each of the last 20 years was obtained from the World Bank.

A first sheet shows the data from all countries of origins, excepted the USA and Western Europe. Other sheets show the data for the 20 countries where our refugees came from, for all countries excepted those of refugees, and from all countries where incidence of TB is at least 50 per 100000 excepted those of refugees.