An outbreak of tuberculosis in a bacillus Calmette-guérin-vaccinated military population

The purpose of this study was to investigate an outbreak of tuberculosis (TB) in a bacillus Calmette-Guérin-vaccinated military population and propose an appropriate method of control. We divided 593 subjects into "close contacts" and "non-close contacts" of an index case and examined all subjects by chest X-radiography (CXR). For "close contacts," we performed several tests for patients with abnormal CXRs. "Non-close contacts" had no pulmonary infiltration and no evidence of TB. We administered tuberculin skin tests (TST) to 21 "close contacts" who had pulmonary infiltrations. Seven patients had a TST > or =18 mm, two of whom had active pulmonary TB. We administered antituberculous agents to all seven patients for 6 months. Fourteen subjects with TSTs <18 mm had no evidence of TB during the 18-month follow-up period. Among the other 178 "close contact" subjects with no infiltrations evident on the initial CXR, one patient developed TB pleuritis. We conclude that it is important to use early treatment for "close contacts" of a TB index case by performing the TST and testing for pulmonary infiltration on CXRs.