Epidemiology, clinical features and outcomes of incident tuberculosis in children in Canada in 2013–2016: results of a national surveillance study

Abstract

PurposeChildhood tuberculosis disease is difficult to diagnose and manage and is an under-recognised cause of morbidity and mortality. Reported data from Canada do not focus on childhood tuberculosis or capture key epidemiologic, clinical and microbiologic details. The purpose of this study was to assess demographics, presentation and clinical features of childhood tuberculosis in Canada.MethodsWe conducted prospective surveillance from 2013 to 2016 of over 2700 paediatricians plus vertical tuberculosis programmes for incident tuberculosis disease in children younger than 15 years in Canada using the Canadian Paediatric Surveillance Program (CPSP).ResultsIn total, 200 cases are included in this study. Tuberculosis was intrathoracic in 183 patients of whom 86% had exclusively intrathoracic involvement. Central nervous system tuberculosis occurred in 16 cases (8%). Fifty-one per cent of cases were hospitalised and 11 (5.5%) admitted to an intensive care unit. Adverse drug reactions were reported in 9% of cases. The source case, most often a first-degree relative, was known in 73% of cases. Fifty-eight per cent of reported cases were Canadian-born Indigenous children. Estimated study rates of reported cases (per 100 000 children per year) were 1.2 overall, 8.6 for all Indigenous children and 54.3 for Inuit children.ConclusionChildhood tuberculosis may cause significant morbidity and resource utilisation. Key geographies and groups have very high incidence rates. Elimination of childhood tuberculosis in Canada will require well-resourced community-based efforts that focus on these highest risk groups.

Strengthening Tuberculosis Services for Children and Adolescents in Low Endemic Settings

“…Unlike the declines seen in the United States, rates of childhood TB in Canada have remained stable over the past 7 years for which there are published data [6]. While childhood TB is largely a disease of the child who is either born or with parents born in a TB-endemic country in the US, and 66% of TB in all ages in Canada occurs in individuals not born in Canada, more than half of childhood TB in Canada occurs among Canadian Indigenous children, reflecting the very high rates and ongoing transmission in those communities [7]. The overall annual rate of childhood TB in Canada between 2013 and 2016 was 1.6/100,000 for all children, 10.2/100,000 for all Indigenous children (i.e., First Nations and Inuit and Metis children), and 100.8/100,000 among Inuit children [7].…”

“…The overall annual rate of childhood TB in Canada between 2013 and 2016 was 1.6/100,000 for all children, 10.2/100,000 for all Indigenous children (i.e., First Nations and Inuit and Metis children), and 100.8/100,000 among Inuit children [7]. In a national study, over 70% of childhood cases had a known contact, usually within the home [7]. Based on hospital and TB program data, childhood TB in the metropolitan immigrant-receiving areas is largely a disease of foreign-born children or the children of foreign-born parents [8].…”

“…The pattern of extrapulmonary disease may differ between countries. For example, in the United States, most central nervous system TB has occurred in children younger than 2 years of age [34], whereas in Canada, older children and adolescents are more often affected [7]. Distinguishing those with pulmonary TB from patients with more common conditions may be difficult: in a recent study, the duration of symptoms was found to differentiate symptomatic adolescents attending a pediatric emergency department with infectious TB from those with pneumonia [35], but given the rarity of TB, routine algorithms to detect TB were considered difficult to implement.…”

“…Retrospective and observational studies have supplied some useful information, especially about the implementation of recommended regimens. Canadian [7] and regional collaborations, such as the Pediatric Tuberculosis European Trials Group [47], have produced representative studies with adequate sample sizes that deal with the unique problems of these settings; it is imperative that these and similar efforts be supported and funded. The strengths of low-burden settings that may uniquely contribute to TB research include more complete and longer follow-up, the ability to closely monitor for drug toxicity and to accurately determine the causes of morbidity and death.…”

Transcriptome-Based Molecular Networks Uncovered Interplay Between Druggable Genes of CD8+ T Cells and Changes in Immune Cell Landscape in Patients With Pulmonary Tuberculosis

“…Granulomas also suppress the host immune responses, as dendritic cells and macrophages were unable to present antigen to lymphocytes (4). It is noteworthy to mention that mycobacteria can induce distinct host responses from asymptomatic conditions to severe pulmonary illness (5). However, underlying immune cell types and their association with the differentially expressed genes in TB and how they contribute to severe infection are not yet fully explored.…”