Using surveillance data to simulate the impact of a hypothetical pre-entry tuberculosis screening programme in Japan

Background Despite a growing burden of foreign-born tuberculosis (TB) patients, Japan does not currently practise pre-entry tuberculosis (TB) screening among foreign-born entrants. Objective To evaluate the impact of a hypothetical pre-entry TB screening programme among new foreign-born entrants into Japan. Method Using publicly available sources, we estimated 1) the number of prevalent TB cases, defined as bacteriologically or clinically confirmed cases among new foreign-born entrants into Japan in 2015, and 2) the yield from a hypothetical pre-entry TB screening programme under three scenarios: Scenario A, in which screening would be required of all applicants intending to stay for 3 months; Scenario B, screening among applicants for visas for settlement purposes; and Scenario C, screening among student and technical intern visa applicants. Results The numbers of prevalent TB cases under Scenarios A, B and C were respectively 492, 54 and 248 out of a total of 328 791, 21 554 and 182 879 applicants, respectively 276, 29 and 137 of whom would be detected via the pre-entry screening programme, giving an yield of respectively 83.9, 134.5 and 74.9 per 100 000 screened under each scenario. Conclusion The yield was the highest under Scenario B; however, the impact was greatest under Scenario A, in that it detected the greatest number of patients and thus contributed the most in reducing the burden of foreign-born TB cases in Japan.