Prevalence of Latent Tuberculosis Infection among Medical Students in South Korea

BACKGROUND: We investigated the prevalence of latent tuberculosis infection (LTBI) among medical students in South Korea. METHODS: Students from one medical school, who were in second- or third-year classes before clerkship course, were enrolled for three consecutive years in the study. A standard questionnaire was given to each participant, and tuberculin skin test (TST), QuantiFERON-TB GOLD In-Tube (QFT-GIT) assay, and chest radiography were performed. RESULTS: A total of 153 participants were enrolled in the study. The mean age of the subjects was 21.9±0.9 years, 105 (68.6%) were male, and 132 (86.3%) had been vaccinated with Bacille Calmette-Guerin (BCG). Four students (2.6%) had a history of contact with tuberculosis (TB) patients during medical practice. No abnormal chest radiograph findings were found for any of the subjects. Of the 153 subjects, 23 (15.0%) tested positive for the TST, and 8 (5.2%) tested positive for the QFT-GIT. The agreement between the two tests was determined to be 0.34 using kappa coefficients. Of the four students who had a history of contact with TB patients, only one subject tested positive for both tests, and the other three students tested negative for both tests. CONCLUSION: A low prevalence of LTBI was found among medical students before clerkship course in South Korea.