Table 2. Incidence rates of tuberculosis and incidence rate ratios among child contacts, by individual antigen ELISpot results at recruitment.

	ESAT-6		CFP-10		Rv3873		Rv3878		Rv3879c		PPD		SKSDa
Test result	positive	negative	positive	negative	positive	negative	positive	negative	positive	negative	positive	negative	positive	negative
Total results, n	272	574	296	550	210	636	169	677	206	640	619	227	547	299
Incident TB cases, n	8	6	8	6	7	7	6	8	5	9	11	3	10	4
Person years at risk	384	740	411	714	294	831	225	899	290	834	826	298	710	414
Unadjusted analysis
Incidence rate per 1000 person years (95% CI)	20.8 (9.0, 41.0)	8.1(3.0, 17.6)	19.4 (8.4, 38.3)	8.4(3.1, 18.2)	23.8 (9.6, 49.1)	8.4(3.4, 17.4)	26.6 (9.8, 58.0)	8.9(3.8, 17.5)	17.2 (5.6 40.1)	10.8 (4.9, 20.5)	13.3 (6.6, 23.8)	10.0 (2.1, 29.3)	14.1 (6.8, 25.9)	9.7(2.6, 24.7)
Incidence rate ratio (95% CI)	2.57 (0.89, 7.40)		2.32 (0.80, 6.68)		2.83 (0.99, 8.07)		3.00 (1.04, 8.63)		1.60 (0.53, 4.76)		1.32 (0.37, 4.74)		1.46 (0.46, 4.65)
P value	0.08		0.12		0.05		0.04		0.4		0.67		0.52
Adjusted analysis b
Incidence rate ratio (95% CI)	2.97 (1.01, 8.73)		2.92 (0.99, 8.59)		3.06 (1.05, 8.95)		3.32 (1.14, 9.71)		1.69 (0.55, 5.17)		2.06 (0.55, 7.68)		3.26 (0.91, 11.70)
P value	0.049		0.052		0.04		0.03		0.36		0.28		0.91

^aStreptokinase streptodornase (SKSD), a non-tuberculosis control antigen.

^bAdjusted for age, sex, isoniazid preventive therapy given to contacts exposed to drug sensitive tuberculosis and BCG vaccination.