Table 1– Prevalence of active tuberculosis (TB) among contacts 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^#	71	24799	878724	3.1	2.2–4.4	2.18	99.4
Index patient smear positive	44	1415	43960	3.3	2.2–5.1	2.04	98.5
Index patient with HIV	6	90	1526	5.4	2.2–12.4	1.14	95.5
Index patient XDR/MDR-TB	6	149	5584	3.4	0.8–12.6	2.88	95.7
Household contacts	68	22390	858422	3.1	2.1–4.5	2.35	98.8
All close contacts	70	22458	860638	3.1	2.2–4.4	2.22	98.8
Casual contacts only	1	34	1492	2.2	1.6–3.0	0.00
Contacts with HIV infection	8	96	391	21.6	8.8–44.1	2.04	92.3
≤5 yrs	21	754	5112	10.0	5.0–18.9	2.35	97.8
5–14 yrs	9	155	1643	8.4	2.8–22.6	2.51	92.5
≥15 yrs	11	127	3614	3.2	2.0–5.3	0.53	87.1
High income
All ages
All^¶	87	5058	308048	1.4	1.1–1.8	1.48	98.7
Index patient smear positive	27	1704	72936	3.3	2.2–4.8	1.08	98.3
Index patient XDR/MDR-TB	2	0	554	0.0		0.00	99.9
Household contacts	29	2047	56221	3.0	2.0–4.4	1.09	98.2
All close contacts	45	3053	127699	1.9	1.3–2.7	1.42	98.7
Casual contacts only	9	73	15607	0.4	0.2–0.6	0.30	79.9
Contacts with HIV infection	2	15	133	11.4	7.0–18.0	0.00	9.0
≤5 yrs	10	212	4057	4.7	3.4–6.4	0.18	79.0
5–14 yrs	9	253	5665	2.9	1.7–5.1	0.56	95.5
≥15 yrs	9	507	17867	2.3	1.1–4.8	1.19	99.0

Data are presented as n, unless otherwise stated. XDR: extensively drug resistant; MDR: multidrug resistant. Countries were classified according to 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, 32–101]; ^¶: [10, 30, 31, 102–184]. Refer to supplementary material for outcomes of individual included studies.