[Five-year Trends in the Results of Tuberculosis Contact Investigations in Congregate Settings, 2019-2023]

The tuberculosis (TB) incidence rate in the Republic of Korea is the second highest among Organisation for Economic Co-operation and Development countries, with a particularly high risk of secondary transmission in congregate settings. This study has analyzed TB cases and contact characteristics in congregate settings from 2019 to 2023 in order to propose management strategies based on the observed trends.

Epidemiological data from the Korea Tuberculosis Network System were analyzed for TB cases reported in congregate settings between 2019 and 2023. This study has examined major settings, such as schools and social welfare facilities, and has assessed the number of cases reported each year, characteristics of contacts, secondary cases, and latent TB infection (LTBI) trends.

The number of TB cases in congregate settings decreased from 8,045 in 2019 to 6,205 in 2023, with an average annual reduction of 6.3%. Cases in schools declined significantly by 58.2% (from 514 in 2019 to 215 in 2023), whereas those in social welfare facilities increased (from 925 in 2019 to 1,038 in 2023). This increase was linked to the growing proportion of elderly contacts in social welfare facilities.

Elderly contacts are at a higher risk of developing TB owing to their immunosuppression and comorbidities, making their management increasingly critical. Since 2023, the Korea Disease Control and Prevention Agency has strengthened LTBI screening for contacts aged 65 years and older and has recommended risk-adjusted interventions to enhance TB prevention among the elderly.