Table 1. Demographic, microbiologic and Mtb exposure characteristics of study participants.
| Cases (n = 23) | TST+ (n = 64) | TSTC (n = 26) | PTST− (n = 39) | p–value | |
| Age, median (range) | 31 (27–35) | 29 (20–38) | 29 (23–49) | 28 (20–45) | ns |
| Male gender, n (%) | 16 (70) | 32 (50) | 13 (50) | 16 (41) | ns |
| Presence of a BCG scar, n (%) | 9/20 (45) | 35/63 (56) | 16/26 (62) | 19/39 (49) | ns |
| Baseline TST size, median (min., max, IQR) | 0 (0,16,0) | 14 (10,28,9) | 0 (0,5,0) | 0 (0,5,0) | p<0.001 |
| 6 month TST size, median (min., max; IQR) | na | na | 18 (10,25,6) | 0 (0,5,0) | p<0.001 |
| Sleeping Proximity to Index Case | |||||
| Same bedroom, n (%) | 17 (27) | 3 (11) | 3 (8) | ||
| Different bedroom, n (%) | 29 (45) | 15 (58) | 16 (41) | ||
| Different house, n (%) | 18 (28) | 8 (31) | 20 (51) | p = 0.041* | |
| Smear Grade of Index Case | |||||
| Grade 1, n (%) | 2 (9) | 9 (14) | 1 (4) | 8 (21) | |
| Grade 2, n (%) | 9 (39) | 27 (42) | 12 (46) | 15 (38) | |
| Grade 3, n (%) | 12 (52) | 28 (44) | 13 (50) | 16 (41) | ns |
| Spoligotype of Index Case where known | n = 21 | n = 58 | n = 24 | n = 34 | |
| M. tuberculosis, n (%) | 11 (52) | 35 (60) | 19 (79) | 27 (79) | |
| M. africanum, n (%) | 10 (48) | 23 (40) | 5 (21) | 7 (21) | ns |
| Days to Positivity of Index Case Cultures | |||||
| Days, median (IQR) | 9 (17) | 12 (17) | 6.5 (10) | 6 (18) | ns |
* Fisher's exact test: p = 0.017 for proximity between TST+ and PTST−. ns = not significant; TST+ = TST positive; TSTC = TST converters; PTST− = persistently TST negative; na = not assessed; IQR = interquartile range.