About 17 percent of employees working at local medical institutions were confirmed with latent tuberculosis infection, a cohort study showed. Only 30 percent of them were receiving treatment.

Latent TB infection is not contagious, but a person with it has inactive TB bacteria inside the body.

Kim Ju-sang, a professor at pulmonology department at Catholic University Korea Incheon St. Mary’s Hospital, released the result of the analysis on the latent TB screening project and cohort composition plan, commissioned by the Korea Centers for Disease Control and Prevention (KCDC).

Kim analyzed data of 857,765 people who underwent interferon-gamma release assay (IGRA) tests as part of the latent TB screening and treatments for workers at collective facilities in 2017.

The result showed that 14.8 percent of them were infected with latent TB. By sex, 11.4 percent of males and 16 percent of females had latent TB infection.

By age, the older they were, the higher the incidence of the disease was. Whereas teenagers had 2.1 percent incidence, the rate went up to 5.4 percent among those in their 20s, 12.4 percent in 30s, 23 percent in 40s, 35.7 percent in 50s, 43.2 percent in 60s, and 44.4 percent in those aged 70 and more.

By facility, 22 percent of workers at public health centers tested positive in latent TB infection. The number went up to 27.5 percent among those at social welfare facilities but down to 18.3 percent among employees at educational institutions. Among employees at medical institutions, 17.3 percent tested positive.

Among people who had latent TB infection, only 31.7 percent started to receive treatment. At public health centers, the number was higher at 41.4 percent, and at private hospitals, 58.6 percent.

About 77 percent of latent TB patients who started treatment have completed the treatment. The possibility to start treatment was higher at medical institutions and postpartum care centers.

After observing people who tested positive in latent TB infection for 14 months on average, Kim found out that the risk of developing TB was seven times higher in patients untreated than those who have completed treatment.

Reasons for incomplete treatment included side effects (40.8 percent), noncompliance (23.5 percent), and lost contact (14.6 percent).

Physicians mostly prescribed 3HR (76.9 percent) for latent TB, followed by 4R with 10.7 percent, and 9H with 8.7 percent. The three therapies’ cure rate marked 78.4 percent, 76.2 percent, and 46.9 percent, respectively.

About 6.8 percent of patients who were treated experienced side effects. The most common one was hepatotoxicity (33.3 percent). Allergy came next with 26.8 percent and gastrointestinal side effect, 22.9 percent.

“The World Health Organization (WHO) emphasizes the prevention of TB infection by latent TB screening and treatment. This study first confirmed that the local project for latent TB screening was effective to prevent TB,” Kim said.

KCDC Director Jeong Eun-kyeong said that TB could be prevented by detecting and treating latent TB.

“For Korea to quickly shake off its image of having the world’s highest TB incidence, intra-governmental cooperation is essential to improve screening and treatment,” she said.

kss@docdocdoc.co.kr

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