TABLE 2.

Prevalence of latent tuberculosis (TB) infection in the contacts of TB patients in low−middle- and high-income countries

	Included studies	Contacts with latent TB infection	Contacts screened	Proportion%	95% CI	τ2	I2
Low−middle income
All ages
All#	76	35788	60557	51.5	47.1−55.8	0.58	98.9
Index patient smear positive	51	19003	33875	52.9	48.9−56.8	0.32	97.7
Index patient with HIV	12	1138	2376	45.7	38.7−52.9	0.22	90.9
Index patient XDR/MDR-TB	6	431	684	61.3	39.1−79.6	1.21	95.2
Household contacts	73	23577	49512	45.4	40.7−50.2	0.69	98.4
All close contacts	73	23577	49643	45.3	40.6−50.1	0.69	98.4
Contacts with HIV infection	8	123	247	53.5	40.6−66.0	0.36	71.4
≤5 yrs	33	5102	12389	35.5	30.3−41.1	0.42	96.6
5−14 yrs	21	6587	11123	53.1	42.0−63.9	1.05	98.6
≥15 yrs	10	11980	14057	65.3	35.5−86.5	3.80	99.6
High income
All ages
All¶	92	79511	284505	28.1	24.2−32.4	0.99	99.5
Index patient smear positive	34	25910	78784	34.8	27.6−42.7	0.96	99.1
Index patient with HIV	1	131	363	36.0	31.2−41.0	0.00
Index patient XDR/MDR-TB	2	287	554	52.6	49.5−55.7	0.00
Household contacts	33	20960	67175	30.0	21.3−40.5	1.80	99.6
All close contacts	29	20213	68738	28.0	18.9−39.4	1.96	99.6
Casual contacts only	7	5779	27383	18.7	11.8−28.5	0.52	99.4
Contacts with HIV infection	3	28	151	25.0	11.4−46.4	0.53	86.6
≤5 yrs	17	2093	6900	16.3	9.2−27.0	1.73	99.2
5−14 yrs	10	1407	4871	18.4	11.8−27.5	0.64	98.4
≥15 yrs	8	6221	12633	41.9	30.5−54.2	0.50	99.4

Data are presented as n, unless otherwise stated. XDR: extensively drug resistant; MDR: multidrug resistant. World Bank Income Gross National Income per capita: low income (≤$1,005 per yr); lower-middle income ($1,006 to $3,975 per yr); upper-middle income ($3,976 to $12,275 per yr); high income (≥12,276 per yr) [22]. ^#: [9, 32, 34, 36–39, 41–43, 48, 49, 52, 55, 57–60, 62–67, 69, 71, 73, 74, 77–79, 81, 83–89, 91, 93–95, 97–101, 185–187, 194–196, 199–201 203–215]; ^¶: [10, 28, 30, 31, 102, 103, 105, 107, 109–111, 115, 116, 119, 121–125, 128–138, 142–145, 147–157, 159–184, 188, 189, 193, 202, 216–233].