Table 1.
Demographic and Mycobacterium tuberculosis exposure characteristics of home household contacts (HHC) who were TST+ at baseline (TST+), remained persistently TST– (PTST–), or TST converted by 3 months (TSTC)
| TSTC N = 42 | PTST− N = 19 | TST+ N = 42 | P value | |
|---|---|---|---|---|
| Demographic factors | ||||
| Age in years, mean (SD) | 26 (14) | 28 (16) | 28 (8) | 0.64 |
| Male gender, n (%) | 11 (26) | 6 (32) | 16 (38) | 0.50 |
| Baseline TST size in mm, mean (SD) | 2.8 (3.7) | 0.6 (2.1) | 16.8 (3.7) | < 0.0001† |
| Presence of BCG scar, n (%) | 24 (57) | 7 (37) | 24 (57) | 0.47 |
| Index case factors | ||||
| AFB smear grade ≥ 1+, n (%) | 39 (92) | 16 (84) | 40 (95) | 0.30 |
| Extent of disease on chest radiograph, n (%) | ||||
| Normal/minimal | 7 (17) | 4 (22) | 11 (26) | 0.61 |
| Moderately advanced | 17 (41) | 5 (28) | 11 (26) | |
| Far advanced | 17 (41) | 9 (50) | 20 (48) | |
| Cough duration in days, median [range] | 84 [14–730] | 90 [21–210] | 90 [21–690] | 0.42 |
| Household exposure factors | ||||
| Biological relationship to index, n (%) | ||||
| Close (sibling, parent, child) | 19 (45) | 11 (58) | 17 (40) | 0.35 |
| Distant (cousin, avuncular) | 10 (24) | 4 (21) | 6 (14) | |
| Unrelated (spouse or other) | 13 (31) | 4 (21) | 19 (45) | |
| Share bed with index, n (%) | 7 (17) | 2 (10) | 11 (26) | 0.30 |
| Care for index, n (%) | 35 (83) | 12 (63) | 31 (74) | 0.22 |
| Share meals with index, n (%) | 38 (90) | 16 (84) | 40 (97) | 0.18 |
| With index > 7–12 hours/day, n (%) | 36 (86) | 14 (74) | 36 (88) | 0.25 |
| With index > 3 days/week, n (%) | 40 (95) | 15 (79) | 37 (90) | 0.14 |
*
TST+ = tuberculin skin test positive; PTST– = persistently TST negative; TSTC = TST converters; BCG = bacille Calmette-Guérin; AFB = acid-fast bacilli.
†
Significant pairwise comparisons TST+ > TSTC and TST+ > PTST–.