Tuberculosis: What is the yield of associate investigations in non-BCG-immunized children with positive tuberculin skin tests?

SETTING: Urban county health department in Tarrant County, Texas, USA. OBJECTIVE: To determine the yield of associate investigations in non-bacille Calmette-Guérin (BCG) immunized children with positive tuberculin skin tests (TSTs). DESIGN: We compared the results of associate investigations of the contacts of 38 TST-positive, non-BCG-immunized pre-school children with the results of contact investigations of 290 culture-confirmed persons with tuberculosis (TB). RESULTS: Associate investigations were more likely than contact investigations to identify persons with culture-confirmed TB and positive TSTs. Contacts identified through associate investigation of non-BCG-immunized pre-school children were 9.4 (95%CI 4.2-22.5) times more likely to have culture-confirmed TB and 2.3 (95%CI 2.0-2.7) times more likely to have positive TSTs than contacts of persons with culture-confirmed TB. CONCLUSION: While conducting associate investigations is labor intensive, these data indicate that associate investigation of pre-school non-BCG-immunized children should be assigned priority in TB control activities, at least equal to the importance of investigating the contacts of culture-proven TB.