1377. Use of Interferon-Gamma Release Assays (IGRAs) Reduced Latent Tuberculosis Infection (LTBI) Diagnosis in Refugee and Immigrant Children

BACKGROUND: For foreign-born children from countries with high tuberculosis (TB) burden, positive tuberculin skin test (TST) results, associated with Bacillus Calmette Guerin (BCG) vaccination, paradoxically increase the risk for overdiagnosis and overtreatment of latent TB infection (LTBI) during immigration. The higher specificity of interferon-gamma release assays, such as QuantiFERON-TB (QFT), may help distinguish LTBI from positive TSTs due to BCG or non-TB Mycobacteria. However, data on QFT usage in pediatric populations, particularly refugee and immigrant children, are sparse. Our objective was to assess the impact of QFT on LTBI diagnosis and treatment in the vulnerable child refugee and immigrant population. METHODS: We initiated a retrospective study of children (≤15 years) seen in Santa Clara County Refugee/Immigrant Clinic for post-immigration TB re-evaluation in 2017. We collected information from the Electronic Disease Notification system and post-immigration clinic records, including laboratory studies, imaging, and clinical impression. The primary outcome was post-immigration LTBI diagnosis in patients with positive pre-immigration TB screening. Patients with prior active TB or LTBI treatment were excluded. RESULTS: 102/135 clinic encounters examined to date were post-immigration encounters. Median age was 9 years (range 14mo to 15y). Most (82.5%) were from Asia, primarily the Philippines (n = 48), Afghanistan (n = 10), Iran (n = 9), and Vietnam (n = 8). Sixty-six (64.7%) had documented BCG vaccination. Among 102 encounters, 71 (69.6%) were of children diagnosed pre-immigration with LTBI based on positive TST and normal chest radiograph. After post-immigration evaluation with retesting by QFT, 13/71 (18%) were diagnosed with LTBI (Table 1). There were no active TB cases among 102 patients, though long-term follow-up varied (mean 5.5 ± 6.5 months). CONCLUSION: QFT use for post-immigration LTBI re-evaluation reduced LTBI diagnosis by 82% in children as young as 2 years old. Preliminary data suggest the preferential use of QFT over TST in non-United States-born children, in accordance with new California Department of Public Health TB screening recommendations for children ≥2 years, could reduce unnecessary diagnosis and treatment of LTBI in refugee and immigrant children. [Image: see text] DISCLOSURES: All authors: No reported disclosures.