Risk of TB development 7 times higher than general public upon family contact

The Korea Disease Control and Prevention Agency (KDCA) published the '2025 Tuberculosis Epidemiological Survey Results' on the 20th. Among those who came into contact with tuberculosis patients, the number of additional TB patients found was 232.7 per 100,000 people, approximately 7 times the TB incidence rate of the total domestic population (33.5 per 100,000).

Domestic TB incidence and mortality rates remain among the highest for member countries of the Organization for Economic Cooperation and Development (OECD). As of 2024, among 38 OECD countries, Korea ranks 2nd in TB incidence and 3rd in mortality.

Last year, out of 17,070 domestic TB patients, 10,669 were aged 65 or older, accounting for 62.5%. Among contacts, the elderly were found to be at the greatest risk of developing TB. The number of additional TB patients found among those aged 80 or older was 96, a 54.8% increase from the previous year (62). The incidence rate for this age group was 496.0 per 100,000, the highest among all age groups. For ages 65-79, it was 207.6, 5-18 was 185.6, and 19-64 was 154.2.

Family contact was particularly dangerous. The incidence rate of additional TB patients among family contacts was 1,517 per 100,000, about 3.6 times higher than those in group facilities and 17.1 times higher than the general population. KDCA researchers analyzed that the characteristic of families living closely together in the same space for long periods increases the risk of TB transmission.

However, the treatment initiation rate for latent TB was lowest among the elderly, who face the greatest contact risk. Latent TB refers to a state where a person is infected with TB bacteria but has no symptoms or contagiousness. Last year, out of 12,524 subjects for latent TB treatment, 6,933 people started treatment, accounting for 55.4%. By age group, 86.4% for ages 5-18, 81.5% for 19-64, and 48.5% for 65-79 started treatment, but for those over 80, it was only 12.6%.

Reluctance to seek treatment among the elderly is backed by concerns about side effects. The elderly often have chronic conditions or take multiple medications simultaneously, increasing the risk of having to discontinue treatment due to drug side effects. In fact, a study analyzing 11,913 domestic latent TB treatment recipients found that the risk of treatment discontinuation due to side effects was 9.09 times higher for patients over 76 compared to those aged 5 or younger. Representative side effects included abnormal skin reactions and liver dysfunction.

There is no vaccine yet to effectively prevent pulmonary tuberculosis in adults. The only currently licensed TB vaccine (BCG) is effective in preventing severe TB in infants and young children but has limited effectiveness in preventing pulmonary TB in adolescents and adults.

The KDCA announced plans to encourage screening and treatment participation among elderly contacts and strengthen follow-up monitoring for those with untreated latent TB.