Declining incidence rate of tuberculosis among close contacts in five years post-exposure: a systematic review and meta-analysis

Table 3 Meta-analysis of active tuberculosis incidence among close contacts during follow-up

Subgroups	Follow-up period	No. of included studies^a	Summarized incidence^b (95% CI)	Heterogeneity
Subgroups	Follow-up period	No. of included studies^a	Summarized incidence^b (95% CI)	I²	P for Q test
Total	1 year	12	2.15% (1.51%-2.80%)	93.72%	< 0.0001
	2 years	21	1.21% (0.93%-1.49%)	92.40%	< 0.0001
	5 years	7	1.11% (0.64%-1.58%)	97.73%	< 0.0001
Index cases were smear +	2 years	6	1.55% (1.08%-2.02%)	87.13%	< 0.0001
Baseline MTB infection testing + ^c	2 years	12	3.80% (2.74%-4.87%)	81.86%	< 0.0001
Baseline MTB infection testing–	2 years	9	0.82% (0.47%-1.18%)	79.65%	< 0.0001
From high TB burden countries^d	2 years	7	1.63% (1.04%-2.21%)	86.46%	< 0.0001
From other countries^d	2 years	14	1.03% (0.71%-1.35%)	93.46%	< 0.0001

Abbreviation: CI Confidence interval, MTB Mycobacterium tuberculosis
^aOnly people who did not receive preventive chemotherapy were included in this analysis
^bMost articles reported the incident tuberculosis (TB) as confirmed cases without coprevalent disease which was defined as confirmed or unconfirmed TB identified at baseline or within 3 months post-exposure
^cMost studies’ baseline MTB infection testing + was defined as a tuberculin skin-test (TST) induration response of ≥ 10 mm in adults or ≥ 5 mm in children. One study [26] defined as QuantiFERON Gold In-Tube Test and one [27] defined as T-SPOT.TB
^dHigh TB burden countries were defined by World Health Organization global TB report 2022 (Geneva: World Health Organization, 2022) [3]

ISSN: 1471-2334