Table 6. Incidence of active tuberculosis in household contacts and IFNγ production levels at baseline.
IFNγ production* | N | Cases | Percentage of TB cases | Incidence Proportion | Person-years | Incidence Rate (#/1000 person-years) |
Negative | 666 | 7 | 21.2 | 1.05 | 1686.9 | 4.1 |
Low | 338 | 6 | 18.2 | 1.78 | 857.9 | 7.0 |
Medium | 688 | 12 | 36.4 | 1.74 | 1798.1 | 6.7 |
High | 281 | 8 | 24.2 | 2.85 | 703.5 | 11.4 |
Total Positive † | 1307 | 26 | 78.8 | 1.99 | 3359.6 | 7.7 |
*Negative: <22pg/mL, Low: 22–99 pg/mL Medium: 100–999 pg/mL, High: ≥1000 pg/mL.
†Total positive: (Negative + Low + Medium + High).