A total of 250 medical personnel in South Korea either had confirmed tuberculosis or acquired inactive TB via exposure to patients in 2015, a report showed Monday.

The report was based on an epidemiological survey on 2,765 hospital personnel in 153 medical institutions which had at least one TB patient, the Korea Centers for Disease Control and Prevention said. The report showed that eight were confirmed TB cases and the remaining 242 were inactive TB cases.

Inactive TB means that bacteria are present in the body but are dormant. The body‘s immune system can suppress TB for years.

Between 60 and 90 percent of inactive TB patients can prevent a TB outbreak if treated well.

By jobs, 123 nurses had inactive TB, with doctors affected reaching 22. The report showed numbers for assistant nurses standing at 16 and other medical staff hitting 68.

TB is a bacteria-related disease that mainly attacks the lungs and is one of the most infectious diseases in the world, along with HIV and malaria.

South Korea had the highest incidence rate of TB among the world’s most developed economies belonging to the 34-member Organization for Economic Cooperation and Development in 2015. A separate OECD report showed that 80 out of every 100,000 South Koreans were infected with the disease in 2015, trailed by Portugal with 23. (Yonhap)