Risk of Occupational Tuberculosis in National Tuberculosis Programme Laboratories in Korea

Setting: Mycobacteriology laboratories in the National Tuberculosis Control Programme in Korea.

Objectives: To determine tuberculosis (TB) risk by type of work among laboratory workers compared to non-laboratory workers.

Design: Retrospective study of TB incidence among technicians involved in acid-fast bacilli smear microscopy or culture and/or drug susceptibility testing (DST) compared with that among managerial/clerical workers.

Results: Two cases developed among 77 non-laboratory workers, two among 88 smear microscopy technicians, and 11 among 76 culture/DST technicians during the observation period. Compared to non-laboratory workers, the relative risk of TB was 1.4 (95% CI 0.2-10.0) among microscopy technicians and 7.8 (95% CI 1.7-34.9) among culture/DST technicians. TB developed among 7/15 DST technicians compared to only 2/59 culture/non-DST technicians. Compared to non-laboratory workers, the relative risk for DST technicians was 21.5 (95% CI 4.5-102.5).

Conclusion: DST led to the highest relative risk among all types of mycobacteriology work, while performing smear microscopy alone did not pose an elevated risk compared to clerical work.