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	1,407	4,871	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].