[Tuberculosis Contact Investigations among Household and Congregate Settings in 2024]

For effective tuberculosis (TB) control, early detection of active TB and treatment of latent TB infection (LTBI), especially among contacts of infected patients, are essential. This study aimed to analyze the 2024 contact investigation results to provide foundational data for TB elimination strategies.

This study analyzed household contact data from the Tuberculosis Investigation Form and congregate setting data from the Tuberculosis Notification Reporting Form registered in the National Tuberculosis Integrated Information System in 2024. The analysis included contacts, secondary TB cases, and LTBI. The distributions were examined by year, age, and the type of congregate facility.

In 2024, a total of 105,989 contacts were investigated in 16,220 households and 3,470 congregate facilities, resulting in the early detection of 250 additional TB cases (235.9/10⁵ contacts). The highest TB incidence rate was observed in contacts aged 70 years and older (316.0/10⁵ contacts). LTBI was diagnosed in 17,537 individuals (29.5%). The highest LTBI rate was also in contacts aged 70 and above (41.9%). Among those with LTBI, treatment was initiated in 7,385 individuals (45.4%), with treatment initiation rates decreasing with age.

The 2024 contact investigation confirmed that older contacts showed higher rates of TB incidence and LTBI but a lower treatment initiation rate. These trends were also observed in 2023. The Korea Disease Control and Prevention Agency promotes screening and treatment for high-risk groups, with LTBI treatment guided by risk-benefit assessments, strengthened education, and public awareness.