[Results of the Tuberculosis Contact Investigation, 2023]

Tuberculosis (TB) is an airborne infectious disease caused by Mycobacterium tuberculosis, which is spread by infected patients. Upon infection, some individuals develop active TB, whereas others remain in a state of latent TB infection (LTBI), in which the bacterium resides without symptoms or transmission, potentially progressing to active TB. The prompt diagnosis and treatment of LTBI are crucial for effective TB management. When TB cases occur, rapid epidemiological investigations are conducted to identify contacts in households and congregate facilities, followed by testing for TB and LTBI. In 2023, 107,804 contacts were investigated across 17,663 households and 3,620 facilities, and 200 additional TB cases (185.5 per 100,000 contacts) were detected. Among household contacts, 99 additional TB cases (460.4 per 100,000 contacts) were detected, 3.9 times higher than the 101 cases (117.0 per 100,000 contacts) among congregate facility contacts and 15.0 times higher than the incidence in the general population (30.6 per 100,000 population). The LTBI rate was 26.1% (14,207) and was similar between household and facility contacts. increased with age, however, treatment initiation rates were low in older age groups. Targeting high-risk contacts for TB and LTBI testing and treatment aims to reduce TB incidence to ≤20 cases per 100,000 by 2027. The Korea Disease Control and Prevention Agency continues to promote screening and treatment among these contacts, emphasizing safety and individualized benefits, even in older age groups.