TB risk by time since US entry among non-US-born residents of Washington State, USA

BACKGROUND: Progress towards TB elimination in the United States will require improved detection and treatment of latent TB infection among non-U.S.-born residents who remain at disproportionate risk of TB disease. To inform targeted testing efforts, we evaluated risk of TB disease among non-U.S.-born residents of Washington State, USA, by region of origin and time from U.S. entry. METHODS: We conducted a retrospective cohort study among non-U.S.-born residents diagnosed with TB disease in Washington State from 2005 to 2014, for which country-specific population estimates were also available. The risk of TB disease among non-U.S.-born residents was estimated by time since U.S. entry, World Bank region of origin, and WHO TB incidence category. RESULTS: Risk of TB disease for non-U.S.-born residents was highest within the first year after U.S. entry. Among persons from countries with high TB incidence who had resided in the United States for more than 20 years, risk for TB remained elevated. CONCLUSION: Elevated risk of developing TB disease among individuals not born in the United States persisted long after U.S. entry, particularly among persons originating from certain regions and from high-burden countries. These findings contribute to evidence supporting a refinement of existing screening guidelines.