Pathways of TB Transmission in Children—A Systematic Review of Molecular Epidemiological Studies

Abstract

The widespread paradigm that younger children usually do not transmit M. tuberculosis complex (Mtbc) to their contacts has not yet been proven by genotypically confirmed transmissions. Therefore, we undertook a systematic review of molecular-epidemiological studies to investigate documented source and secondary TB (tuberculosis) cases among children. We searched the literature published before August 2022 using PubMed, Cochrane, and Google Scholar databases. PRISMA statement was used for systematic review. Of 312 records retrieved, 39 studies including children aged below 15 years offered epidemiological links between cluster members. In the 39 studies from 16 countries, 225 children were reported as cluster members of whom the overwhelming majority were infected by adults. Only 3 children—of those were 2 children aged below 10—were reported to be the definite source cases of 11 other children and 1 adult with genotypically matched Mtbc isolates. To date, molecular-epidemiological studies involving children with verified transmission links are scarce. As far as the heterogeneity of the studies we identified allows, we could conclude that the results confirm the paradigm that children aged below 10 hardly ever transmit Mtbc to others. The true extent of TB transmission through children may, however, be underestimated by those selected studies.

Pediatric Tuberculosis: A Review of Evidence-Based Best Practices for Clinicians and Health Care Providers

“…Infection prevention and control (IPC) in health care services and other settings at high risk for transmission is a pillar of global TB prevention efforts. Children with TB are often considered unlikely to transmit TB (due to paucibacillary disease and a relative lack of cough) [ 6 , 79 ], but children can and do transmit TB [ 6 ]. Further, both children and adults are at risk for TB transmission in health care facilities and households without adequate infection control measures in place.…”

Empfehlungen für die Umgebungsuntersuchungen bei Tuberkulose – Update 2023

“…Kinder unter 10 Jahren kommen als Ansteckungsquelle nur ausnahmsweise in Frage [12][13][14][15] (siehe 2.3.). Es wird daher empfohlen, alle Personen ab einem Alter von 10 Jahren, die in den letzten 2-6 Monaten (ggf.…”

“…Ein einziger Hustenstoß erzeugt etwa die gleiche Aerosolmenge wie 5 Minuten lauten Sprechens [11]. Kinder unter 10 Jahren kommen als Infektionsquelle in aller Regel nicht in Betracht, da sie seltener eine mikroskopisch positive Tuberkulose aufweisen, wenig oder gar nicht husten oder aber ihnen ein für die Erregerverbreitung erforderlicher, ausgeprägter Hustenstoß fehlt [12][13][14][15].…”

Empfehlungen für die Umgebungsuntersuchungen bei Tuberkulose – Update 2023

“…Ein einziger Hustenstoß erzeugt etwa die gleiche Aerosolmenge wie 5 Minuten lauten Sprechens [11]. Kinder unter 10 Jahren kommen als Infektionsquelle in aller Regel nicht in Betracht, da sie seltener eine mikroskopisch positive Tuberkulose aufweisen, wenig oder gar nicht husten oder aber ihnen ein für die Erregerverbreitung erforderlicher, ausgeprägter Hustenstoß fehlt [12][13][14][15]. Dieses Dokument wurde zum persönlichen Gebrauch heruntergeladen.…”