Prevalence and risk factors of latent tuberculosis among Korean healthcare workers using whole-blood interferon-γ release assay.

Because healthcare workers (HCWs) are at high risk for tuberculosis (TB) infection, it is essential to research the prevalence of latent TB infection (LTBI) and to implement health interventions including early treatment of LTBI and TB infection control measures. The purpose of the study was to determine the prevalence and risk factors for LTBI using interferon-γ release assay (IGRA) among HCWs in South Korea. The cross-sectional study was carried in the National Health Insurance Service Ilsan Hospital, which is a 740-bed general hospital, South Korea. HCWs who participated in this survey were required to complete a questionnaire and IGRA was performed. Of the 1,655 HCWs, 271 results were positive and the prevalence of LTBI was 16% (95% CI; 15-18%). In the multivariate analysis, age (OR; 2.201, 95% CI; 1.911-2.536, P < 0.001), male sex (OR; 1.523, 95% CI; 1.133-2.046, P = 0.005), contact active TB patients (OR; 1.461, 95% CI; 1.061-2.010, P = 0.02) and diabetes (OR; 2.837, 95% CI; 1.001-8.044, P = 0.05) were significant risk factors for LTBI. LTBI among HCWs in Korea, although prevalent, might not exceed the background level of the general population. Because contact with active TB patients has been identified as a risk factor for LTBI, more effective TB infection control measures are essential in healthcare facilities and congregate settings.