Table 3– Prevalence of microbiologically proven tuberculosis (TB) in the contacts of TB patients in low–middle- and high-income countries

	Included studies	Contacts with active TB	Contacts screened	Proportion %	95% CI	τ²	I²
Low–middle income
All ages
All^#	38	8633	841721	1.2	0.9–1.8	1.00	95.9
Index patient smear positive	17	150	10241	1.2	0.8–1.8	0.47	87.4
Index patient with HIV	4	35	1317	1.9	0.8–4.5	0.53	89.7
Index patient XDR/MDR-TB	2	2	1056	0.2	0.0–0.8	0.00	82.7
Household contacts	36	8336	811231	1.4	1.0–2.1	1.16	97.9
All close contacts	37	8426	824541	1.4	1.0–2.1	1.14	97.8
Casual contacts only	1	12	1492	0.7	0.4–1.3	0.00
High income
All ages
All^¶	21	264	45897	0.4	0.2–0.7	1.56	96.1
Index patient smear positive	6	108	5970	0.7	0.3–1.9	1.08	97.6
Index patient XDR/MDR-TB	2	0	554	0.0		0.00	99.9
Household contacts	6	116	5459	1.4	0.8–2.5	0.33	92.6
All close contacts	14	187	30269	0.4	0.2–0.9	1.35	96.9
Casual contacts only	1	0	275	0.0		1.87

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, 33, 34, 38, 42–46, 54, 56–58, 60, 62, 63, 66–68, 70–73, 75, 76, 79, 82, 84, 85, 88, 90, 91, 95, 97, 99–101, 234]; ^¶: [30, 31, 111–113, 116, 119, 120, 122, 134, 135, 137, 138, 148–150, 154, 165, 166, 170, 177].