Abstract
Objectives
Tuberculosis (TB) is an airborne infectious disease that requires early detection and contact management to prevent community transmission. Timely diagnosis and treatment of latent tuberculosis infection (LTBI) can reduce the risk of progression to active TB. This study analyzed the results of TB contact investigations conducted in 2025 to evaluate the status of contact management and provide baseline evidence for future TB control policies.
Methods
Household and congregate setting contacts of patients with pulmonary TB registered in the Korea Tuberculosis Network System in 2025 were analyzed. The analysis included contacts, additional TB cases, and individuals diagnosed with LTBI, with findings stratified by age group and congregate setting type.
Results
A total of 100,124 contacts from 15,280 households and 3,617 congregate settings were investigated, resulting in the early detection of 233 additional TB cases (232.7/105 contacts). The rate of additional TB cases was highest among contacts aged ≥80 years (496.0/105 contacts). LTBI was diagnosed in 13,797 individuals (24.7%), and 6,933 of 12,524 eligible individuals (55.4%) initiated treatment. LTBI rates increased with age, whereas treatment initiation rates decreased with age.
Conclusions
Contacts aged ≥80 years had the highest rates of additional TB cases and LTBI but the lowest treatment initiation rate, highlighting the need for active screening and improved treatment uptake in older contacts. Although the LTBI treatment initiation rate improved compared with the previous year, a sustained management system to support treatment completion is required. The Korea Disease Control and Prevention Agency plans to strengthen age-tailored management for this age group, support LTBI treatment among contacts of patients with multidrug-resistant TB, and enhance follow-up among untreated individuals.
Keywords: Tuberculosis, Latent tuberculosis infection, Contact investigation, Household contacts, Congregate setting
Key messages
① What is known previously?
The incidence rate of tuberculosis (TB) among household and congregate setting contacts was approximately 16.2 and 4.6 times higher, respectively, than that in the general population.
② What new information is presented?
In 2025, 233 additional TB cases were identified among contacts (232.7 per 105 contacts), representing an incidence rate approximately 7 times higher than that in the general population. Latent tuberculosis infection (LTBI) was diagnosed in 13,797 (24.7%) patients, of whom 6,933 (55.4%) initiated treatment.
③ What are implications?
Completion of LTBI treatment can help reduce the risk of progression to active TB by 90%. Older contacts had higher TB and LTBI rates but lower treatment initiation rates, highlighting the need for strengthened treatment uptake and follow-up of untreated individuals. Additionally, supporting LTBI treatment for contacts of patients with multidrug-resistant TB can strengthen a prevention-focused management system.
Introduction
Tuberculosis (TB) is a Class 2 infectious disease under the “Infectious Disease Control and Prevention Act” and is a respiratory infectious disease transmitted by the Mycobacterium tuberculosis complex expelled into the air through droplets generated by coughing, sneezing, etc. Even if infected with the M. tuberculosis complex, most people remain in a state of latent tuberculosis infection (LTBI), with no clinical symptoms and no transmission to others, and only about 5–10% are known to progress to active TB [1].
According to the World Health Organization, approximately 10.7 million TB patients and 1.23 million deaths from TB were reported worldwide in 2024, and the Republic of Korea (ROK) had the second-highest TB incidence rate and the third-highest TB-related mortality rate among member countries of the Organisation for Economic Co-operation and Development [2]. In 2025, the TB incidence rate in the ROK was 33.5 per 100,000 population [3], and the TB incidence rate among contacts of TB patients was 232.7 per 100,000 contacts, which was approximately seven times higher than that of the general population.
A TB contact investigation is conducted to interrupt community transmission through the early detection of additional TB cases and to prevent the development of active TB through LTBI treatment. It is classified into household contact investigations and congregate setting contact investigations. The scope of a contact investigation is determined for contacts at high risk of infection or developing active TB, based on a comprehensive consideration of the infectivity of the TB patient, the duration of contact, the characteristics of the contact setting, and the characteristics of the contacts [1,4].
Contact investigation is being implemented as one of the key initiatives of the Third National Strategic Plan for TB Control in the ROK (2023–2027). This report analyzes characteristics by age group and congregate setting based on the results of the 2025 TB contact investigation and aims to provide baseline data for the development of future TB control policies.
Methods
1. Subject of Analysis
The test results of contacts of TB patients who were notified and reported to the Korea Tuberculosis Network System (KTB net) from January 1 to December 31, 2025, as recorded in the Korea Tuberculosis Network System as of February 1, 2026, were analyzed.
The chest X-ray and LTBI test results of 17,464 household contacts of 15,280 respiratory TB patients and 82,660 congregate setting contacts in 3,617 congregate settings were analyzed.
2. Tests and Diagnostic Criteria
A household contact investigation is conducted in the following cases: first, for family members and cohabitants who lived in the same household or had regular contact with a respiratory TB patient (disease codes: A15.00–A16.91, A19.0–A19.9) from 3 months before the initiation of TB treatment until 2 weeks after treatment initiation, and second, when a case of extrapulmonary TB occurs in a child aged ≤8 years.
A congregate setting contact investigation is conducted under the following circumstances: first, when a TB patient’s respiratory specimen test result is confirmed to be positive; second, when the index patient’s respiratory specimen test result is negative but a cavity is identified on chest X-ray; third, when two or more active TB cases occur within 6 months in a congregate setting (within the epidemiologically transmissible range), regardless of infectivity; and fourth, when TB occurs in a child under 5 years of age, including extrapulmonary TB.
Contacts are selected based on a comprehensive consideration of the duration of contact with the index patient, the characteristics of the contact setting, and the contact’s risk of TB infection, with priority given to those who had contact for 8 hours or more per day or a cumulative total of 40 hours or more during the estimated infection period. Selected contacts undergo TB testing and LTBI testing (tuberculin skin test and interferon-gamma release assay), and all contacts undergo follow-up chest X-ray 3 months after the initial test. For contacts diagnosed with LTBI, treatment to prevent the development of active TB is provided at the treating physician’s discretion after considering the index patient’s drug susceptibility test results, the age of the person to be treated, risk factors for hepatotoxicity, treatment adherence, and chest X-ray findings [1,4].
3. Analytical Methods
The analysis was performed using Microsoft Excel 2021 (Microsoft) to analyze contacts by age group and congregate setting, additional TB cases identified through contact investigation, individuals with LTBI, and the status of LTBI treatment.
Results
1. Results of the 2025 Tuberculosis Contact Investigation
In 2025, an investigation of 100,124 household and congregate setting contacts of TB patients was conducted. By age group, contacts aged 19–64 years accounted for the largest proportion at 54.4% (54,489), followed by those aged ≥80, 65–79, 5–18, and 0–4 years at 19.3% (19,356), 19.2% (19,270), 6.5% (6,465), and 0.5% (544), respectively (Table 1). Among all contacts, 98,980 received TB testing, for a TB testing rate of 98.9%. Additional TB cases were identified among household contacts (100 cases; 572.6 per 100,000 contacts) and congregate setting contacts (133 cases; 160.9 per 100,000 contacts), for a total of 233 additional TB cases (232.7 per 100,000 contacts). The incidence rate of additional TB cases per 100,000 contacts was the highest among those aged ≥80 years, at 496.0.
Table 1. Contact investigation results (2025).
| Total | Household | Congregate setting | ||
|---|---|---|---|---|
| No. of pulmonary TB cases | - | 15,280 | - | |
| No. of contacts investigated | - | - | 3,617 | |
| No. of contacts | 100,124 | 17,464 | 82,660 | |
| TB test | TB tested | 98,980 (98.9) | 16,990 (97.3) | 81,990 (99.2) |
| TB case (cases/105 contacts) | 233 (232.7) | 100 (572.6) | 133 (160.9) | |
| LTBI test | No. of eligible cases for testinga) | 58,062 | 16,013 | 42,049 |
| LTBI testedb) | 55,827 (96.2) | 15,722 (98.2) | 40,105 (95.4) | |
| LTBI casesc) | 13,797 (24.7) | 4,296 (27.3) | 9,501 (23.7) | |
| No. of eligible cases for treatmentd) | 12,524 | 4,020 | 8,504 | |
| Performed treatmente) | 6,933 (55.4) | 2,809 (69.9) | 4,124 (48.5) | |
| Treatment result | ||||
| Treatment completef) | 4,133 (59.6) | 1,722 (61.3) | 2,411 (58.5) | |
| Treatment discontinuedg) | 701 (10.1) | 257 (9.1) | 444 (10.8) | |
| Treatment ongoingh) | 2,099 (30.3) | 830 (29.5) | 1,269 (30.8) | |
Unit: case (%), case (cases/105). TB=tuberculosis; –=not available; LTBI=latent tuberculosis infection; MDR=multidrug-resistant. a)Close contacts who were exposed to a patient with TB for 8 or more continuous hours in a day or for a cumulative total of 40 hours or more during the infectious period, excluding those with a history of TB or LTBI. b)Individuals who underwent LTBI testing. c)Individuals who tested positive among those who underwent LTBI testing. d)Individuals who tested positive for LTBI with no history of TB or LTBI treatment. e)Among LTBI treatment candidates, those who have a recorded treatment start date, excluding those who had abnormal pre-treatment test results and did not start treatment, and those who were contacts of patients with MDR-TB. f)Individuals among LTBI treatment initiators whose treatment was “completed.” g)Individuals among LTBI treatment initiators whose treatment “discontinued” due to reasons such as progression to active TB, adverse reactions, or death. h)Individuals among LTBI treatment initiators who are still undergoing treatment as of the data extraction date (February 1, 2026).
Excluding contacts with a history of TB or LTBI, 58,062 individuals were eligible for LTBI testing, of whom 55,827 underwent testing, resulting in an LTBI screening rate of 96.2%. A total of 13,797 individuals were diagnosed with LTBI through testing, yielding an LTBI rate of 24.7%. The age-specific LTBI rate tended to increase with age, except among children aged 0–4 years (Table 2).
Table 2. Contact investigation results by age (2025).
| Age (yr) |
No. of contacts | TB test | LTBI test | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| TB tested | TB case (cases/105 contacts) |
No. of eligible cases for testinga) |
LTBI testedb) | LTBI casec) | Performed treatmentd) | Treatment result | |||||
| Treatment completee) | Treatment discontinuedf) | Treatment ongoingg) | |||||||||
| Total | 100,124 | 98,980 | 233 (232.7) |
55,827 | 13,797 (24.7) |
12,524 | 6,933 (55.4) |
4,133 (59.6) |
701 (10.1) |
2,099 (30.3) |
|
| 0–4 | 544 | 537 | 1 (183.8) |
472 | 105 (22.2) |
102 | 100 (98.0) |
52 (52.0) |
0 (0.0) |
48 (48.0) |
|
| 5–18 | 6,465 | 6,418 | 12 (185.6) |
4,312 | 255 (5.9) |
236 | 204 (86.4) |
122 (59.8) |
6 (2.9) |
76 (37.3) |
|
| 19–64 | 54,489 | 53,738 | 84 (154.2) |
30,723 | 6,318 (20.6) |
5,550 | 4,523 (81.5) |
2,784 (61.6) |
428 (9.5) |
1,311 (29.0) |
|
| 65–79 | 19,270 | 19,086 | 40 (207.6) |
10,342 | 3,845 (37.2) |
3,538 | 1,716 (48.5) |
986 (57.5) |
195 (11.4) |
535 (31.2) |
|
| ≥80 | 19,356 | 19,201 | 96 (496.0) |
9,978 | 3,274 (32.8) |
3,098 | 390 (12.6) |
189 (48.5) |
72 (18.5) |
129 (33.1) |
|
| Household | 17,464 | 16,990 | 100 (572.6) |
15,722 | 4,296 (27.3) |
4,020 | 2,809 (69.9) |
1,722 (61.3) |
257 (9.1) |
830 (29.5) |
|
| 0–4 | 257 | 251 | 1 (389.1) |
251 | 71 (28.3) |
68 | 68 (100.0) |
37 (54.4) |
0 (0.0) |
31 (45.6) |
|
| 5–18 | 1,553 | 1,522 | 10 (643.9) |
1,495 | 154 (10.3) |
144 | 127 (88.2) |
72 (56.7) |
2 (1.6) |
53 (41.7) |
|
| 19–64 | 9,980 | 9,695 | 47 (470.9) |
8,997 | 2,195 (24.4) |
2,042 | 1,683 (82.4) |
1,060 (63.0) |
149 (8.9) |
474 (28.2) |
|
| 65–79 | 4,224 | 4,128 | 20 (473.5) |
3,741 | 1,442 (38.5) |
1,350 | 808 (59.9) |
481 (59.5) |
87 (10.8) |
240 (29.7) |
|
| ≥80 | 1,450 | 1,394 | 22 (1,517.2) |
1,238 | 434 (35.1) |
416 | 123 (29.6) |
72 (58.5) |
19 (15.4) |
32 (26.0) |
|
| Congregate settings | 82,660 | 81,990 | 133 (160.9) |
40,105 | 9,501 (23.7) |
8,504 | 4,124 (48.5) |
2,411 (58.5) |
444 (10.8) |
1,269 (30.8) |
|
| 0–4 | 287 | 286 | 0 (0.0) |
221 | 34 (15.4) |
34 | 32 (94.1) |
15 (46.9) |
0 (0.0) |
17 (53.1) |
|
| 5–18 | 4,912 | 4,896 | 2 (40.7) |
2,817 | 101 (3.6) |
92 | 77 (83.7) |
50 (64.9) |
4 (5.2) |
23 (29.9) |
|
| 19–64 | 44,509 | 44,043 | 37 (83.1) |
21,726 | 4,123 (19.0) |
3,508 | 2,840 (81.0) |
1,724 (60.7) |
279 (9.8) |
837 (29.5) |
|
| 65–79 | 15,046 | 14,958 | 20 (132.9) |
6,601 | 2,403 (36.4) |
2,188 | 908 (41.5) |
505 (55.6) |
108 (11.9) |
295 (32.5) |
|
| ≥80 | 17,906 | 17,807 | 74 (413.3) |
8,740 | 2,840 (32.5) |
2,682 | 267 (10.0) |
117 (43.8) |
53 (19.9) |
97 (36.3) |
|
Unit: case (%), case (cases/105). TB=tuberculosis; LTBI=latent tuberculosis infection; MDR=multidrug-resistant. a)Close contacts who were exposed to a patient with TB for 8 or more continuous hours in a day or for a cumulative total of 40 hours or more during the infectious period, excluding those with a history of TB or LTBI. b)Individuals who underwent LTBI testing. c)Individuals who tested positive among those who underwent LTBI testing. d)Among LTBI treatment candidates, those who have a recorded treatment start date, excluding those who had abnormal pre-treatment test results and did not start treatment, and those who were contacts of patients with MDR-TB. e)Individuals among LTBI treatment initiators whose treatment was “completed.” f)Individuals among LTBI treatment initiators whose treatment “discontinued” due to reasons such as progression to active TB, adverse reactions, or death. g)Individuals among LTBI treatment initiators who are still undergoing treatment as of the data extraction date (February 1, 2026).
Among individuals with LTBI, 12,524 were eligible for treatment after excluding contacts of patients with multidrug-resistant or extensively drug-resistant TB, persons with a history of TB or LTBI, and persons with abnormal pre-treatment test results (liver function, platelet count, and kidney function). Of these, 6,933 individuals (55.4%) initiated treatment. This number represented an 8.0%p increase compared with the previous year (7,718 persons, 47.4%) and tended to decrease with increasing age. As of the data extraction date (February 1, 2026), the LTBI treatment completion rate was 59.6%; 10.1% discontinued treatment due to developing TB, adverse effects, or death, and 30.3% were still on treatment (Table 1).
2. Results of the 2025 Household Contact Investigation
In 2025, the number of household contacts was 17,464, representing a 7.6% decrease from the previous year (18,893). This finding reflected the decline in TB patients in the ROK and the increasing proportion of single-person households. By age group, those aged 19–64 years accounted for the largest proportion at 57.1% (9,980), followed by those aged 65–79 and 5–18 years at 24.2% (4,224) and 8.9% (1,553), respectively. Through TB testing, 100 additional TB cases were identified, and the incidence rate of additional TB cases was 572.6 per 100,000 household contacts, 17.1 times higher than that in the general population (33.5 per 100,000). The incidence rate of additional TB cases was the highest among contacts aged ≥80 years, at 1,517.2 per 100,000 contacts. The LTBI rate was 27.3% (4,296). By age group, the LTBI rate was the highest and the lowest among those aged 65–79 (38.5%, 1,442) and 5–18 years (10.3%, 154), respectively. The LTBI treatment initiation rate was 69.9% (2,809); it was the lowest and highest among those aged ≥80 (29.6%, 123) and 0–4 years (100.0%, 68), respectively (Table 2).
3. Results of the 2025 Congregate Setting Contact Investigation
In 2025, a total of 3,617 congregate setting contact investigations were conducted in accordance with the criteria for conducting such investigations, representing a 4.2% increase from the previous year (3,470). By type of congregate setting, workplaces accounted for the largest proportion at 38.2% (1,381 investigations), followed by social welfare facilities at 34.2% (1,238 investigations) and healthcare institutions at 16.0% (579 investigations) (Figure 1). The incidence rate of additional TB cases per 100,000 contacts was 204.2, 193.4, and 118.5 in social welfare facilities, healthcare institutions, and other facilities, respectively, while no additional TB cases were identified in military or police facilities.
Figure 1. Number of tuberculosis contact investigations conducted in congregate settings (2021–2025).
The number of congregate setting contacts was 82,660, representing a 5.1% (4,436) decrease from the previous year (87,096). By age group, contacts aged 19–64 years accounted for the largest proportion at 44,509 (53.8%), followed by those aged ≥80 and 65–79 years at 17,906 (21.7%) and 15,046 (18.2%), respectively. There were 133 additional TB cases (160.9 per 100,000 contacts). The TB incidence rate per 100,000 contacts was the highest among contacts aged ≥80 years, at 413.3, and no additional TB cases were identified among contacts aged 0–4 years.
The LTBI rate among congregate setting contacts was 23.7% (9,501), and the treatment initiation rate was 48.5% (4,124). By age group, the LTBI rate was the highest among those aged 65–79 years at 36.4% (2,403), whereas the treatment initiation rate was the lowest among those aged ≥80 years at 10.0% (267) (Table 2).
By type of congregate setting, the LTBI rate among contacts in social welfare facilities was 29.7% (5,626); however, the treatment initiation rate was the lowest at 35.8% (1,844), and the treatment discontinuation rate was the highest at 12.7% (234). In addition, the LTBI treatment initiation rate was lower in healthcare institutions with a high proportion of older patients (48.2%, 498) and in social welfare facilities (35.8%, 1,844) than in other congregate settings (Table 3).
Table 3. Contact investigation results of patients with infectious TB in congregate settings (2025).
| Total | Educational facilities | Clinics/hospitals | Military/police units | Correctional facilities | Social welfare facilities | Work places | Others | ||
|---|---|---|---|---|---|---|---|---|---|
| No. of investigations | 3,617 | 199 | 579 | 24 | 34 | 1,238 | 1,381 | 162 | |
| No. of contacts | 82,660 | 12,226 | 12,929 | 588 | 486 | 38,679 | 15,221 | 2,531 | |
| TB test | TB tested | 81,990 (99.2) |
11,905 (97.4) |
12,850 (99.4) |
586 (99.7) |
482 (99.2) |
38,509 (99.6) |
15,158 (99.6) |
2,500 (98.8) |
| TB case (cases/105 contacts) |
133 (160.9) |
13 (106.3) |
25 (193.4) |
0 (0.0) |
1 (205.8) |
79 (204.2) |
12 (78.8) |
3 (118.5) |
|
| LTBI test | No. of eligible cases for testinga) | 42,049 | 6,017 | 5,657 | 350 | 308 | 19,813 | 8,814 | 1,090 |
| LTBI testedb) | 40,105 (95.4) |
5,702 (94.8) |
5,335 (94.3) |
333 (95.1) |
293 (95.1) |
18,919 (95.5) |
8,468 (96.1) |
1,055 (96.8) |
|
| LTBI casec) | 9,501 (23.7) |
354 (6.2) |
1,240 (23.2) |
21 (6.3) |
101 (34.5) |
5,626 (29.7) |
1,997 (23.6) |
162 (15.4) |
|
| No. of eligible cases for treatmentd) | 8,504 | 317 | 1,033 | 18 | 81 | 5,154 | 1,759 | 142 | |
| Performed treatmente) | 4,124 (48.5) |
237 (74.8) |
498 (48.2) |
16 (88.9) |
43 (53.1) |
1,844 (35.8) |
1,385 (78.7) |
101 (71.1) |
|
| Treatment result | |||||||||
| Treatment completef) | 2,411 (58.5) |
145 (61.2) |
272 (54.6) |
11 (68.8) |
26 (60.5) |
1,038 (56.3) |
869 (62.7) |
50 (49.5) |
|
| Treatment discontinuedg) | 444 (10.8) |
16 (6.8) |
48 (9.6) |
2 (12.5) |
3 (7.0) |
234 (12.7) |
135 (9.7) |
6 (5.9) |
|
| Treatment ongoingh) | 1,269 (30.8) |
76 (32.1) |
178 (35.7) |
3 (18.8) |
14 (32.6) |
572 (31.0) |
381 (27.5) |
45 (44.6) |
|
Unit: case (%), case (cases/105). TB=tuberculosis; LTBI=latent tuberculosis infection; MDR=multidrug-resistant. a)Close contacts who have been exposed to a patient with TB for 8 or more continuous hours in a day or for a cumulative total of 40 hours or more during the infectious period, excluding those with a history of TB or LTBI. b)Individuals who underwent LTBI testing. c)Individuals who tested positive among those who underwent LTBI testing. d)Individuals who tested positive for LTBI with no history of TB or LTBI treatment. e)Among LTBI treatment candidates, those who have a recorded treatment start date, excluding those who had abnormal pre-treatment test results and did not start treatment, and those who were contacts of patients with MDR-TB. f)Individuals among LTBI treatment initiators whose treatment was “completed.” g)Individuals among LTBI treatment initiators whose treatment “discontinued” due to reasons such as progression to active TB, adverse reactions, or death. h)Individuals among LTBI treatment initiators who are still undergoing treatment as of the data extraction date (February 1, 2026).
Discussion
According to the results of the 2025 TB contact investigation, 233 additional TB cases (232.7 per 100,000 contacts) were detected through early case finding, and the LTBI rate was 24.7% (Figure 2). In particular, the number of additional TB cases among contacts aged ≥80 years (96) increased by 54.8% compared with the previous year (62), and the TB incidence rate (496.0 per 100,000 contacts) was also the highest. In addition, as the age of contacts increased, the LTBI rate increased, whereas the treatment initiation rate showed a decreasing trend. This finding may be attributed to the combined effects of decreased immune function, concomitant chronic diseases, and possible reactivation of past infection in older adults [5], suggesting the need for more proactive screening and treatment for elderly contacts.
Figure 2. Overall TB contact investigation results (2021–2025).
TB=tuberculosis; LTBI=latent tuberculosis infection.
Although the number of household contacts has continued to decrease due to factors such as the decline in respiratory TB patients in the ROK and the increase in single-person households, the incidence of additional TB cases among household contacts remained approximately 3.6 times higher than that among congregate setting contacts and approximately 17.1 times higher than that in the general population. This finding was consistent with a previous study [6] and suggests that prolonged, close exposure within households plays an important role in increasing the risk of TB transmission. Among congregate setting contacts, the number of TB cases and contact investigations increased due to an increase in investigations at long-term care facilities associated with a higher proportion of older patients, whereas the overall number of contacts appears to have decreased due to a decline in TB cases in middle and high schools.
The LTBI rate did not differ substantially between household contacts (27.3%) and congregate setting contacts (23.7%); however, the treatment initiation rates differed, at 69.9% and 48.5%, respectively. This finding may be attributed to factors such as greater awareness of the risk of within-household TB transmission among household contacts, resulting in higher treatment initiation, whereas congregate setting contacts tend to perceive the risk of transmission as low because of lower contact intensity. Beginning in 2025, to encourage treatment among congregate setting contacts, the Ministry of the Interior and Safety expanded the assessment population for the local government joint evaluation indicator, “LTBI treatment management rate among contacts of TB patients,” from household contacts to include congregate setting contacts. Consequently, the LTBI treatment initiation rate among all contacts increased by 8.0%p compared with the previous year (47.4%).
LTBI treatment is one of the key strategies for preventing active TB, and completion of LTBI treatment is known to exert a preventive effect of up to 90% compared with no treatment [7,8]. In particular, because a previous study [9] confirmed the preventive effect of LTBI treatment even in older adults, it is important to comprehensively consider the risks and benefits of treatment rather than limiting treatment solely on the basis of advanced age. Accordingly, the Korean guidelines for tuberculosis (5th edition) strengthened its recommendation to actively consider LTBI treatment for contacts aged ≥65 years. Furthermore, given that treatment discontinuation is more often attributable to failure of follow-up management and treatment non-adherence than to adverse drug effects [10], a continuous management system is needed to support patients from treatment initiation through treatment completion.
The Korea Disease Control and Prevention Agency (KDCA) supports treatment management by linking LTBI treatment prescription records with the National Health Insurance Service and is working to strengthen contact management by expanding support for chest computed tomography (CT) screening costs (from July 1, 2025) for the early detection of TB among household contacts at high risk of developing TB. In addition, levofloxacin treatment for LTBI among contacts of patients with multidrug-resistant TB will be incorporated into the 2026 National Tuberculosis Control Guidelines, and National Health Insurance reimbursement will apply from January 1, 2026, establishing a foundation for preventing the development of multidrug-resistant TB, which is difficult to treat and imposes a substantial social burden.
However, this study is limited in that it was conducted using data registered in KTB net as of the data extraction date; therefore, it could not include cases that were not registered or cases for which information was entered after the data extraction date. In addition, the exposure settings and underlying conditions of individual contacts could not be taken into account. Because this study was based on an analysis of data from a single time point, it could not evaluate long-term treatment persistence or trends in the development of TB. Therefore, future follow-up studies based on the establishment of a cohort of contacts with LTBI are needed.
The KDCA will review expanding support for screening costs needed for the early detection of TB cases and will strengthen treatment management for individuals with LTBI as well as follow-up observation of individuals with untreated LTBI.
Acknowledgments
We thank to Tuberculosis Epidemiological Response Teams (TERTs) in Regional Center for Disease Control and Prevention, TERTs in local government by province and district.
Declarations
Ethics Statement: Not applicable.
Funding Source: None.
Conflict of Interest: The authors have no conflicts of interest to declare.
Author Contributions: Conceptualization: SMH. Data curation: SMH. Formal analysis: SMH. Investigation: SMH, JAS, SJC, JEK. Supervision: SEL. Visualization: SMH. Writing – original draft: SMH. Writing – review & editing: JAS, SJC, JEK, SEL.
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