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

Table 4 Meta-analysis of active tuberculosis prevalence and Mycobacterium tuberculosis infection prevalence at baseline among close contacts

Subgroups	No. of included studies^a	Summarized prevalence of active TB^b (95% CI)	Heterogeneity
Subgroups	No. of included studies^a	Summarized prevalence of active TB^b (95% CI)	I²	P for Q test
Total	18	2.68% (2.02%-3.35%)	95.67%	< 0.0001
From high TB burden countries^e	4	5.55% (2.98%-8.11%)	85.90%	< 0.0001
From other countries^e	14	2.16% (1.49%-2.82%)	95.89%	< 0.0001
Subgroups	No. of included studies^c	Summarized prevalence of MTB infection (95% CI)	Heterogeneity
Subgroups	No. of included studies^c	Summarized prevalence of MTB infection (95% CI)	I²	P for Q test
Total	20	46.30% (37.18%-55.41%)^d	99.58%	< 0.0001
Testing by TST	18	48.37% (38.58%-58.16%)	99.61%	< 0.0001
Testing by IGRA	6	41.24% (21.06%-61.42%)	99.67%	< 0.0001
Index cases were smear +	5	53.94% (41.76%-66.12%)	98.90%	< 0.0001
From high TB burden countries^e	6	52.80% (38.62%-66.98%)	98.99%	< 0.0001
From other countries^e	14	43.51% (32.32%-54.71%)	99.65%	< 0.0001

Abbreviation CI Confidence interval, IGRA Interferon gamma release assay, MTB Mycobacterium tuberculosis, TB Tuberculosis, TST Tuberculin skin test
^aOf the included 31 studies, 18 of them investigating the baseline active tuberculosis (TB) prevalence were included in summarized active TB prevalence analysis
^bMost articles’ active TB prevalence at baseline among close contacts included coprevalent disease which was defined as confirmed or unconfirmed TB identified at baseline or within 3 months post-exposure
^cOf the included 31 studies, 20 of them investigating the baseline Mycobacterium tuberculosis infection (MTB) infection prevalence were included in Summarized MTB infection prevalence analysis. Most studies’ MTB infection was defined as a tuberculin skin-test induration response of ≥ 10 mm in adults or ≥ 5 mm in children. Several articles defined as both TST and IGRA
^dMTB infection was defined as TST ≥ 10 mm in adults or ≥ 5 mm in children other than only IGRA were used [26, 27]
^eHigh TB burden countries were defined by World Health Organization global TB report 2022 (Geneva: World Health Organization, 2022) [3]

ISSN: 1471-2334