Latent tuberculosis among adult children of immigrant parents from countries with a high incidence of tuberculosis compared to adult children of parents from countries with a low incidence of tuberculosis

Background: Treatment for latent tuberculosis (TB) is traditionally based on the result of the tuberculin skin test (TST) which is often falsely positive. The Interferon gamma release assays (IGRA) are more specific but considerably more expensive. Several studies have implied that living with immigrants from countries with a high incidence of TB increases the risk for latent TB. Objectives: To compare the incidence of latent TB in young native Israelis born to immigrant parents from countries with a high incidence of TB to those for whom both parents were born in countries with a low incidence of TB. Methods: Young native Israelis with a pre-occupational TST test of 10 mm and above were tested for QuantiFERON-TB Gold. Comparisons were made between second generation immigrants from high incidence of tuberculosis countries to those of low incidence tuberculosis countries. Results: Of 102 patients, 71 were born to parents both of whom were from low risk countries, 14 to one parent from a high risk country and 17 to parents both of whom were from a high risk country. The risk for latent TB was significantly higher if both parents were born in a high risk country compared to both parents being from a low risk country (p=0.0334, Fisher exact test) or if one parent was born in a low risk country (p=0.0394). Conclusion: The risk for latent TB is significantly higher in second generation immigrants if both parents were born in a high risk country. IGRA should be considered before treatment to patients with a positive TST if at least one parent was born in a low risk country.