Setting: Singapore, a city-state with a tuberculosis (TB) incidence rate of 47 per 100000 population in 2000.
Objectives: 1) To report our experience with contact investigation and latent TB infection (LTBI) treatment in high-risk contacts with unknown human immunodeficiency virus (HIV) status in correctional facilities (CFs) (prisons/drug rehabilitation centres); and 2) to compare the yield of contact screening in this setting with that in the community (household/family) setting.
Methods: The tuberculin skin test (TST) readings of 704 CF contacts screened from 1999 to 2001 were compared with those of 2729 household/family contacts who underwent screening in 2000.
Results: Respectively eight (1.1%) and 20 (0.7%) active TB cases were detected among the CF and community contacts. A significantly higher proportion of CF contacts had first (non-conversion) TST readings > or =15 mm (39% vs. 22%, OR 2.3; 95%CI 1.9-2.7; P < 0.001), and 10-14 mm (26% vs. 18%, OR 1.6; 95%CI 1.3-2.0; P < 0.001) and TST conversion (43% vs. 20%, OR 2.9; 95%CI 1.7-4.9; P < 0.001). LTBI treatment was started in 65% of the CF contacts screened; 87% completed treatment.
Conclusion: We found a high LTBI rate among CF contacts, presenting an opportunity for intervention.