Towards the elimination of paediatric tuberculosis in high-income, immigrant-receiving countries: a 25-year conventional and molecular epidemiological case study

Tuberculosis among children visiting friends & relatives

BACKGROUND

Most paediatric tuberculosis (TB) cases in low-TB-incidence countries involve children born to migrant families. This may be partially explained by trips to their countries of origin for visiting friends and relatives (VFR). We aimed to estimate the risk of latent TB infection (LTBI) and TB in children VFR.

METHODS

We conducted a prospective multicentric observational study in Catalonia (Spain) from June 2017 to December 2019. We enrolled children aged < 15 years with a negative tuberculin skin test (TST) at baseline and at least one parent from a high-TB-incidence country, and who had travelled to their parent's birth country for ≥21 days. TST and QuantiFERON-TB Gold Plus (QFT-Plus) were performed within 8-12 weeks post-return. LTBI was defined as a TST ≥5 mm and/or a positive QFT-Plus.

RESULTS

Five hundred children completed the study, equivalent to 78.2 person-years of follow-up (PYFU). Thirteen children (2.6%) were diagnosed with LTBI (16.6/per100 PYFU, 95%CI = 8.8-28.5), including two cases (0.4%) of TB (2.5/per100 PYFU, 95%CI = 0.3-9.3). LTBI incidence rates remained high after excluding BCG-vaccinated children (9.7/per100 PYFU, 95%CI = 3.9-20.0). Household tobacco smoke exposure was associated with LTBI (aOR = 3.9, 95%CI = 1.1-13.3).

CONCLUSIONS

The risk of LTBI in children VFR in high-TB-incidence countries may equal, or perhaps even exceed, the infection risk of the native population. The primary associated risk factor was the presence of smokers in the household. Furthermore, the incidence rate of active TB largely surpassed that of the countries visited. Children VFR in high-TB-incidence countries should be targeted for diagnostic and preventive interventions.

Immigrant child health in Canada: a scoping review

INTRODUCTION

Understanding the health of immigrant children from birth to 18 years of age is important given the significance of the early childhood years and complexity of factors that may influence the health status of immigrant populations. Thus, the purpose of this review was to understand the extent and nature of the literature on the health of immigrant children in Canada.

METHODS

We conducted a scoping review of the literature. The review was focused on studies of first-generation and second-generation immigrant children aged 0-18 years. We completed standardised data extraction of immigration status, immigration route, age of children, data source, health or clinical focus, country of origin and major findings.

RESULTS

In total, 250 published papers representing data from 237 studies met the inclusion criteria for this study. A total of 178 articles used quantitative methodologies (mostly survey and cross-sectional study designs), 54 used qualitative methodologies and 18 used mixed methodologies. The articles considered in this review included 147 (59%) focusing on physical health, 76 (30%) focusing on mental health and 37 (15%) focusing on the social aspects of health for refugee and first-generation and second-generation immigrant children across the provinces and territories of Canada.

CONCLUSIONS

Several literature gaps exist with respect to child immigrant health in Canada. For instance, there are no exclusive studies on immigrant boys and limited studies on children of international students.

How much do smear-negative patients really contribute to tuberculosis transmissions? Re-examining an old question with new tools

BACKGROUND

Sputum smear microscopy is a common surrogate for tuberculosis infectiousness. Previous estimates that smear-negative patients contribute 13-20% of transmissions and are, on average, 20 to 25% as infectious as smear-positive cases are understood to be high. Herein, we use an ideal real-world setting, a comprehensive dataset, and new high-resolution techniques to more accurately estimate the true transmission risk of smear-negative cases.

METHODS

We treated all adult culture-positive pulmonary TB patients diagnosed in the province of Alberta, Canada from 2003 to 2016 as potential transmitters. The primary data sources were the Alberta TB Registry and the Provincial Laboratory for Public Health. We measured, as primary outcomes, the proportion of transmissions attributable to smear-negative sources and the relative transmission rate. First, we replicated previous studies by using molecular (DNA) fingerprint clustering. Then, using a prospectively collected registry of TB contacts, we defined transmission events as active TB amongst identified contacts who either had a 100% DNA fingerprint match to the source case or a clinical diagnosis. We supplemented our analysis with genome sequencing on temporally and geographically linked DNA fingerprint clusters of cases not identified as contacts.

FINDINGS

There were 1176 cases, 563 smear-negative and 613 smear-positive, and 23,131 contacts. Replicating previous studies, the proportion of transmissions attributable to smear-negative source cases was 16% (95% CI, 12-19%) and the relative transmission rate was 0.19 (95% CI, 0.14-0.26). With our combined approach, the proportion of transmission was 8% (95% CI, 3-14%) and the relative transmission rate became 0.10 (95% CI, 0.05-0.19).

INTERPRETATION

When we examined the same outcomes as in previous studies but refined transmission ascertainment with the addition of conventional epidemiology and genomics, we found that smear-negative cases were ∼50% less infectious than previously thought.

FUNDING

Alberta Innovates Health Solutions.

Socioeconomic inequalities in 29 childhood diseases: evidence from a 1,500,000 children population retrospective study

BACKGROUND

Socioeconomic position (SEP) powerfully affects health status in the childhood population. However, the knowledge of which diseases are more affected by SEP and whose outcomes could be improved by having a more equitable society remains uncertain on a population basis.

METHODS

We measured socioeconomic and gender inequalities in the pre-COVID-19 era for 29 diseases in the entire childhood population in Catalonia to identify which diseases are most impacted by inequalities. This population-based study included 1,449,816 children under 15 years old from 2014 to 2017 (48.52% girls) and each of their registered diagnoses within the Catalonia National Health System. We calculated frequency measures by SEP and their sex ratios for each disease. We estimated four regression-based inequality measures: slope index of inequality, relative index of inequality (RII), absolute population-attributable fraction, and population-attributable fraction.

RESULTS

Twenty-five of the 29 diseases examined showed SEP inequalities. The diseases with the greatest inequalities in both sexes were tuberculosis, obesity, adjustment and anxiety disorders, essential hypertension, poisoning, short gestation, low birth weight, foetal growth retardation and intrauterine hypoxia and birth asphyxia and trauma (RII ≥ 2.0); only food allergy showed the opposite pattern (RII < 1.0). Overall, 80,188 (7.80%) of the disease events in boys and 74,921 (8.88%) in girls would be avoided if all children had the same disease rate as those in the medium-high SEP group, with tuberculosis, intrauterine hypoxia and birth asphyxia and trauma, obesity, and short gestation, low birth weight, foetal growth retardation being those that could be reduced the most in relative terms, and dermatitis, injuries, acute bronquitis, and being overweight those that could be reduced the most in absolute terms. Girls present higher RII than boys for respiratory allergy, asthma, dermatitis, being overweight, and obesity (p < 0.05). In contrast, boys showed higher RII compared to girls only in congenital anomalies (p < 0.05).

CONCLUSIONS

Socioeconomic and gender inequalities are widely present in childhood health. This indicates that SEP plays a common role in their development although it varies in magnitude according to each disease. It is also a phenomenon that comprises all SEP groups in society. Action needs to be taken to ensure a fairer start in life in terms of health.

Towards elimination of childhood and adolescent tuberculosis in the Netherlands: an epidemiological time-series analysis of national surveillance data

BACKGROUND

Tuberculosis (TB) in children and adolescents is a sentinel event for ongoing transmission. In the Netherlands, epidemiological characteristics of childhood and adolescent TB have not been fully evaluated. Therefore, we aimed to assess TB epidemiology within this population to provide guidance for TB elimination.

METHODS

A retrospective time-series analysis using national surveillance data from 1993-2018 was performed in children (aged <15 years) and adolescents (aged 15-19 years) with TB. Poisson regression models offset with log-population size were used to estimate notification rates and rate ratios. Trends in notification rates were estimated using average annual percentage changes (AAPC) based on the segmented linear regression analysis.

RESULTS

Among 3899 children and adolescents with TB notified during 1993-2018, 2418 (62%) were foreign-born (725 (41.3%) out of 1755 children and 1693 (78.9%) out of 2144 adolescents). The overall notification rate in children was 2.3 per 100 000 person-years, declining steadily during the study period (AAPC -10.9%, 95% CI -12.6--9.1). In adolescents, the overall notification rate was 8.4 per 100 000 person-years, strongly increasing during 1993-2001 and 2012-2018. Compared to Dutch-born children and adolescents, substantially higher notification rates were observed among African-born children and adolescents (116.8 and 316.6 per 100 000 person-years, respectively). Additionally, an increasing trend was observed in African-born adolescents (AAPC 18.5%, 95% CI 11.9-25.5). Among the foreign-born population, those from countries in the horn of Africa contributed most to the TB caseload.

CONCLUSION

TB notification rate among children was low and constantly declining across different demographic groups. However, heterogeneities were shown in adolescents, with an increasing trend in the foreign-born, particularly those from Africa.

Epidemiology of tuberculosis among children and adolescents in the USA, 2007-17: an analysis of national surveillance data

BACKGROUND

Understanding tuberculosis epidemiology among children and adolescents informs treatment and prevention efforts, and efforts to eliminate disparities in tuberculosis incidence and mortality. We sought to describe the epidemiology of children and adolescents with tuberculosis disease in the USA, including tuberculosis incidence rates by parental country of birth and for US territories and freely associated states, which have not been previously described.

METHODS

We analysed data for children aged younger than 15 years and adolescents aged 15-17 years with tuberculosis disease reported to the National Tuberculosis Surveillance System during 2007-17, and calculated tuberculosis incidence rates using population estimates from the US Census Bureau.

FINDINGS

During 2010-17, 6072 tuberculosis cases occurred among children and adolescents; of these, 5175 (85%) of 6072 occurred in the 50 US states or the District of Columbia and 897 (15%) of 6072 in US-affiliated islands. In US states, 3520 (68%) of 5175 cases occurred among US-born people overall, including 2977 (76%) of 3896 children and 543 (42%) of 1279 adolescents. The incidence rate among children and adolescents was 1·0 per 100 000 person-years during 2007-17 and declined 47·8% (95% CI -51·4 to -44·1) during this period. We observed disproportionately high tuberculosis rates among children and adolescents of all non-white racial or ethnic groups, people living in US-affiliated islands, and children born in or with parents from tuberculosis-endemic countries.

INTERPRETATION

Overall, tuberculosis incidence among children and adolescents in the USA is low and steadily declining, but additional efforts are needed to eliminate disparities in incidence and mortality.

FUNDING

US Centers for Disease Control and Prevention.

Tuberculosis among northern Manitoba First Nations, 2008-2012: program performance on- and off-reserve

OBJECTIVES

The objectives of this study were to: (1) report tuberculosis (TB) program performance for northern First Nations in the province of Manitoba; (2) present methods for TB program performance measurement using routinely collected surveillance data; and (3) advance dialogue on performance measurement of Canadian TB programs.

METHODS

Data on a retrospective cohort of people diagnosed with TB in Manitoba between January 1, 2008 and December 31, 2010, and their contacts, were extracted from the Manitoba TB Registry. Performance measures based on US-CDC were analyzed. Adjusted probability ratios (aPR) and 95% confidence intervals (CIs) were reported with comparisons between on-/off-reserve First Nations, adjusted for age, sex, and treatment history.

RESULTS

A cohort of n = 149 people diagnosed with TB and n = 3560 contacts were identified. Comparisons off-/on-reserve: Treatment completion (aPR = 1.03; 95% CI 0.995-1.07); early detection (aPR = 0.87; 95% CI 0.57-1.33); HIV testing and reporting (aPR = 0.42; 95% CI 0.21-0.83); pediatric TB (age < 15 years) (aPR = 1.20; 95% CI 0.47-3.06); retreatment for TB (aPR = 0.93; 95% CI 0.89-0.97); contact elicitation (aPR = 0.94; 95% CI 0.84-1.05); contact assessment (aPR = 0.69; 95% CI 0.50-0.94). Pediatric (ages < 15 years) TB incidence in northern Manitoba was 37.1 per 100,000/year.

CONCLUSION

TB program performance varies depending on residence in a reserve or non-reserve community. Action is urgently needed to address TB program performance in terms of contact investigation and HIV testing/reporting for First Nations off-reserve and to address high rates of pediatric TB in northern Manitoba. First Nations collaboration and models of care should be considered both on- and off-reserve to improve TB program performance.