Table 2. Exposure characteristics[6] associated with persistently negative latent Mycobacterium tuberculosis infection among household contacts of culture-confirmed pulmonary TB cases in India.
| Characteristics of HHCs | Overall | LTBIa | pLTBI-b | Relative Risk (95% CI) |
|---|---|---|---|---|
| (N = 799) | (N = 732) | (N = 67) | ||
| Spouse of the index or mother of the child | ||||
| No | 527 (66%) | 474 (65%) | 53 (79%) | Ref |
| Yes | 267 (34%) | 253 (35%) | 14 (21%) | 1.05 (0.58–1.89) |
| Primary caregiver | ||||
| No | 473 (82%) | 450 (82%) | 23 (88%) | Ref |
| Yes | 104 (18%) | 101 (18%) | 3 (12%) | 1.07 (0.32–3.59) |
| Share the same bed | ||||
| No | 625 (80%) | 569 (79%) | 56 (84%) | Ref |
| Yes | 158 (20%) | 147 (21%) | 11 (16%) | 1.23 (0.65–2.37) |
| Sleep in the same room | ||||
| No | 428 (55%) | 392 (55%) | 36 (54%) | Ref |
| Yes | 355 (45%) | 324 (45%) | 31 (46%) | 1.05 (0.65–1.70) |
| Index case coughing | ||||
| No | 17 (2%) | 16 (2%) | 1 (1%) | Ref |
| Yes | 781 (98%) | 715 (98%) | 66 (99%) | 0.96 (0.13–6.93) |
| Index case Smear positivity | ||||
| No | 254 (32%) | 226 (31%) | 28 (42%) | Ref |
| Yes | 545 (68%) | 506 (69%) | 39 (58%) | 0.75 (0.46–1.23) |
| Living in the same household | ||||
| No | 24 (3%) | 23 (3%) | 1 (1%) | Ref |
| Yes | 774 (97%) | 708 (97%) | 66 (99%) | 1.86 (0.28–13.39) |
| Daily meet with index case | ||||
| No | 25 (3%) | 23 (3%) | 2 (3%) | Ref |
| Yes | 773 (97%) | 708 (96%) | 65 (97%) | 1.13 (0.28–4.60) |
| >1 adult TB index case in the household | ||||
| No | 47 (28%) | 41 (27%) | 6 (38%) | Ref |
| Yes | 121 (72%) | 111 (73%) | 10 (62%) | 0.75 (0.27–2.05) |
Abbreviations: HHC, household contact; TB, tuberculosis; LTBI, latent tuberculosis infection; pLTBI-, persistently negative latent tuberculosis infection.
a Defined as new QuantiFERON TB Gold Test-in-tube positivity (>0.35IU/mL), new tuberculin skin test positive reaction (≥5mm induration) and/or active TB disease at follow up.
b Defined as negative tuberculin skin test (<5mm) and negative QuantiFERON TB Gold Test-in-tube (<0.35IU/mL) at both baseline and up to 12 months following exposure to the adult index TB case.