Is Universal Screening Necessary? Incidence of Tuberculosis among Tibetan Refugees Arriving in Calgary, Alberta

Abstract

Background. Canadian policy requires refugees with a history of tuberculosis (TB) or abnormal chest radiograph to be screened after arrival for TB. However, Tibetan refugees are indiscriminately screened, regardless of preimmigration assessment. We sought to determine the incidence of latent (LTBI) and active TB, as well as treatment-related outcomes and associations between preimmigration factors and TB infection among Tibetan refugees arriving in Calgary, Alberta. Design. Retrospective cohort study including Tibetan refugees arriving between 2014 and 2016. Associations between preimmigration factors and incidence of latent and active TB were determined using Chi-square tests. Results. Out of 180 subjects, 49 percent had LTBI. LTBI was more common in migrants 30 years of age or older (P = 0.009). Treatment initiation and completion rates were high at 90 percent and 76 percent, respectively. No associations between preimmigration factors and treatment completion were found. A case of active TB was detected and treated. Conclusion. Within this cohort, the case of active TB would have been detected through the usual postsurveillance process due to a history of TB and abnormal chest radiograph. Forty-nine percent had LTBI, compared to previously quoted rates of 97 percent. Tibetan refugees should be screened for TB in a similar manner to other refugees resettling in Canada.

Initiation and completion of treatment for latent tuberculosis infection in migrants globally: a systematic review and meta-analysis

“…The 39 included publications contained data on 31 598 migrants positive for LTBI. Studies were done in 13 countries, across three WHO regions (European region, region of the Americas, and Western Pacific region): Australia (n=4 studies), [31][32][33][34] Canada (n=3), [35][36][37] Germany (n=1), 38 Israel (n=1), 39 Japan (n=1), 40 the Netherlands (n=2), 41,42 Norway (n=2), 43,44 South Korea (n=1), 45 Spain (n=3), [46][47][48] Sweden (n=1), 49 Switzerland (n=1), 50 UK (n=4), [51][52][53][54] and USA (n=15). [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] In total, 25 studies with outcome data on 8764 migrants were used to calculate the proportion of individuals initiating treatment.…”

“…[55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] In total, 25 studies with outcome data on 8764 migrants were used to calculate the proportion of individuals initiating treatment. [33][34][35][36][37][38][39][41][42][43]48,[50][51][52][53][54][55][56][58][59][60]65,66,68,69 3A). Demographic and patient factors associated with noninitiation of treatment reported in the studies were being of sub-Saharan African origin 55 and being a refugee from sub-Saharan Africa, northern Africa, or the Middle East.…”

“…52 35 studies with outcome data on 25 629 migrants (of whom 15 516 completed treatment) were used to calculate the proportion of individuals completing treatment subsequent to initiation. [32][33][34][35][36][37][38][39][40][41][42]44,45,[47][48][49][50][51][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] The pooled estimate for the true proportion of LTBI treatment completion among migrants initiating treatment was 74% (95% CI 66- Analysing by treatment regimen, migrants treated with 4 months of rifampicin were significantly more likely to complete treatment (89% [95% CI 67-97]; p=0•020) than migrants prescribed 9 months of isoniazid (ref); no other treatment regimen showed significant differences (table; figure 3B).…”

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Active and latent tuberculosis in refugees and asylum seekers: a systematic review and meta-analysis

“…The mean age, reported by 33% of studies [4,10,31,35,39,51,52,57,62,68,77,78,83,84,88,93,94], ranged from 3.5 to 39 years, with the lowest prevalence in a study that included only children (mean age 3.5 years). Only 21% of studies reported the prevalence by gender.…”