Clinical characteristics and measures of Mycobacterium tuberculosis infection in adults and children in recent household contact with a tuberculosis index case
| All subjects(n = 82) | Children(n = 29) | Adults(n = 53) | |
| Mean (SD) age (years)† | 22.8 (18.1) | 2.9 (2.6) | 33.8 (12.8) |
| % with documented BCG vaccination | 75.6 (62/82) | 100 (29/29) | 62.2 (33/53) |
| TST (%)† | |||
| Positive*† | 69.2 (54/78) | 53.6 (15/28) | 78.0 (39/50) |
| Not read | 4.9 (4/82) | 3.5 (1/29) | 5.7 (3/53) |
| T-SPOT.TB (%) | |||
| Positive† | 75.0 (60/80) | 92.6 (25/27) | 66.0 (35/53) |
| Indeterminate | 1.2 (1/81) | 3.6 (1/28) | 0 (0/53) |
| QTF (%) | |||
| Positive | 40.9 (29/71) | 44.4 (8/18) | 39.6 (21/53) |
| Indeterminate | 4.1 (3/74) | 14.3 (3/21) | 0 (0/53) |
| Mean (SD) M tuberculosis contact score† | 6.4 (5.6) | 10.2 (3.5) | 4.3 (5.4) |
| Proportion with high M tuberculosis contact score (⩾4)‡† | 59.8 (49/82) | 93.1 (27/29) | 41.5 (22/53) |
Data shown as % (n) unless otherwise stated.
BCG, Bacille Calmette-Guérin (BCG vaccination documented, documented on the clinic card or the presence of a BCG scar); QTF, Quantiferon-Gold; TST, tuberculin skin test (TST ⩾10 mm classified as positive).
†Significant difference between adults and children (indeterminate results for interferon γ release assay excluded); *p⩽0.0001 for mean contact score between adults and children (two-sided t test).
‡High M tuberculosis contact score defined as a score ⩾4; low score as <4.
T-SPOT.TB was preferentially completed in children when <10 ml blood available.
Failed phlebotomy was defined as 10 ml blood not obtained in children: 3.4% (1/29) for T-SPOT.TB and 27.6% (8/29) for QTF.
Significant difference (McNemar χ2 test; p<0.05) between the proportions of subjects with positive test results in the following groups: TST vs T-SPOT.TB in children: p = 0.007; TST vs QTF in all subjects: p<0.001; TST vs QTF in adults: p<0.001; T-SPOT.TB vs QTF in all subjects: p<0.001; T-SPOT.TB vs QTF in adults: p<0.001; T-SPOT.TB vs QTF in children: p<0.020.