Recommendations for the screening of paediatric latent tuberculosis infection in indigenous communities: a systematic review of screening strategies among high-risk groups in low-incidence countries

Diagnosis of tuberculosis infection in children with a novel skin test and the traditional tuberculin skin test: An observational study

BACKGROUND

A novel skin test-called Diaskintest (DT)-containing specific M. tuberculosis antigens is in clinical use in the Russian Federation (RF). This test may improve diagnosis of tuberculosis (TB) infection. The use and performance of the DT was described and compared to the tuberculin skin test (TST).

METHODS

Data on children <18 years referred to a TB reference centre (Jan/2018- Dec/2019) with ≥1 DT and TST result available were analysed. An immune correlate of TB infection was defined as a positive TST (≥10 mm induration) or a positive DT (any induration).

RESULTS

Of 2710 included cases, the median age was 9.0 (IQR 5.7-13.1) years and 97.5% were BCG immunised. Overall, 1976 (79.9%) were TB uninfected, 724 (26.7%) had an immune correlate of TB infection and 10 (0.4%) TB disease. Reasons for referral were: positive or increasing skin test results in routine screening (992, 36.6%), screening before admission to a health care institution (501, 18.5%) and TB contact (457, 16.9%). DT was positive in 11.7% (308/2625) and TST in 63.1% (467/740) (Kappa 0.08, 95% CI:0.013-0.14). A positive DT was associated with older age (OR 1.16 (95% CI: 1.13-1.19) per year). Among TB contacts DT positivity was associated with contagiousness: highest proportion of positivity of 12.0% was observed when the index case was smear positive.

CONCLUSION

In a setting with universal BCG vaccination and regular screening with TST, DT was used to rule out TB infection as TST was commonly positive. We found an association of DT positivity and contagiousness of the index case in children contacts. These observations may suggest improved specificity and sensitivity of DT compared to TST.

Pooled sputum testing by Xpert® MTB/RIF Ultra for active tuberculosis case finding among high-risk groups in a low-incidence area: a prospective study

BACKGROUND

Early detection and treatment of tuberculosis (TB) are of great importance to stop its spread. However, optimising the active case findingstrategy is critical to improving its feasibility in regions where TB is epidemic.

METHOD

The different pooled ratios between TB-positive and TB-negative sputum specimens were evaluated and a pooling ratio of 5:1 was used for the active case finding screening by Xpert MTB/RIF Ultra among high-risk groups in Beijing.

RESULTS

The sensitivity of pooling ratio at 5:1 was 97.5% (39/40). Between October 2022 and March 2023, among 17,681 participants, 1729 metthe active case finding criteria and were screened by 350 5:1 sputum pools by Xpert MTB/RIF Ultra. Four pools (1.1%) tested positive and were further confirmed as definite active TB cases. In our study population with high TB incidence (231/100,000), the cost for detection of individual patients was reduced by 77.4% at a 5:1 pooling ratio.

CONCLUSIONS

pooled sputum testing at a suitable ratio using Xpert MTB/RIF Ultra provides a rapid, efficient, and cost-effective method for active TB case finding among high-risk groups in a low-incidence area.

Research Questions and Priorities for Pediatric Tuberculosis: A Survey of Published Systematic Reviews and Meta-Analyses

Background. Advancing a research agenda designed to meet the specific needs of children is critical to ending pediatric TB epidemic. Systematic reviews are increasingly informing policies in pediatric tuberculosis (TB) care and control. However, there is a paucity of information on pediatric TB research priorities. Methodology. We searched MEDLINE, EMBASE, Web of Science, and the Cochrane Library for systematic reviews and meta-analyses on any aspect related to pediatric TB published between 2015 and 2021. We used the UK Health Research Classification System (HRCS) to help us classify the research questions and priorities. Findings. In total, 29 systematic reviews, with 84 research questions, were included in this review. The four most common research topics in the area of detection were 43.33% screening and diagnosis of TB, 23.33% evaluation of treatments and therapeutic interventions, 13.34% TB etiology and risk factors, and 13.34% prevention of disease and conditions and promotion of well-being. The research priorities focused mainly on evaluating TB diagnosis by improving yield through enhanced in specimen collection or preparation and evaluating of bacteriological TB diagnostic tests. Other topics of future research were developing a treatment for TB in children, assessing the use of IPT in reducing TB-associated morbidity, evaluating the prioritization of an IPT-friendly healthcare environment, and providing additional guidance for the use of isoniazid in the prevention of TB in HIV-infected children. Conclusion. There is a need for more systematic reviews on pediatric TB. The review identified several key priorities for future pediatric TB research mainly in the domain of (1) “Detection, screening and diagnosis,” “Development of Treatments and Therapeutic Interventions,” and “Prevention of Disease and Conditions, and Promotion of Well-Being.” These domains are very relevant in the research component of the roadmap towards ending TB in children. It also will serve as an additional action in the WHO End TB strategy.

Tuberculosis in Adolescents and Young Adults: Emerging Data on TB Transmission and Prevention among Vulnerable Young People

Adolescents and young adults (AYA, ages 10-24 years) comprise a uniquely important but understudied population in global efforts to end tuberculosis (TB), the leading infectious cause of death by a single agent worldwide prior to the COVID-19 pandemic. While TB prevention and care strategies often overlook AYA by grouping them with either children or adults, AYA have particular physiologic, developmental, and social characteristics that require dedicated approaches. This review describes current evidence on the prevention and control of TB among AYA, including approaches to TB screening, dynamics of TB transmission among AYA, and management challenges within the context of unique developmental needs. Challenges are considered for vulnerable groups of AYA such as migrants and refugees; AYA experiencing homelessness, incarceration, or substance use; and AYA living with HIV. We outline areas for needed research and implementation strategies to address TB among AYA globally.

High food insecurity in Latinx families and associated COVID-19 infection in the Greater Bay Area, California

BACKGROUND

Food insecurity impacts nearly one-in-four Latinx households in the United States and has been exacerbated by the novel coronavirus or COVID-19 pandemic.

METHODS

We examined the impact of COVID-19 on household and child food security in three preexisting, longitudinal, Latinx urban cohorts in the San Francisco Bay Area (N = 375 households, 1875 individuals). Households were initially recruited during pregnancy and postpartum at Zuckerberg San Francisco General Hospital (ZSFG) and UCSF Benioff prior to the COVID-19 pandemic. For this COVID-19 sub-study, participants responded to a 15-min telephonic interview. Participants answered 18 questions from the US Food Security Food Module (US HFSSM) and questions on types of food consumption, housing and employment status, and history of COVID-19 infection as per community or hospital-based testing. Food security and insecurity levels were compared with prior year metrics.

RESULTS

We found low levels of household food security in Latinx families (by cohort: 29.2%; 34.2%; 60.0%) and child food security (56.9%, 54.1%, 78.0%) with differences between cohorts explained by self-reported levels of education and employment status. Food security levels were much lower than those reported previously in two cohorts where data had been recorded from prior years. Reported history of COVID-19 infection in households was 4.8% (95% Confidence Interval (CI); 1.5-14.3%); 7.2% (95%CI, 3.6-13.9%) and 3.5% (95%CI, 1.7-7.2%) by cohort and was associated with food insecurity in the two larger cohorts (p = 0.03; p = 0.01 respectively).

CONCLUSIONS

Latinx families in the Bay Area with children are experiencing a sharp rise in food insecurity levels during the COVID-19 epidemic. Food insecurity, similar to other indices of poverty, is associated with increased risk for COVID-19 infection. Comprehensive interventions are needed to address food insecurity in Latinx populations and further studies are needed to better assess independent associations between household food insecurity, poor nutritional health and risk of COVID-19 infection.

A systematic review of BCG vaccination policies among high-risk groups in low TB-burden countries: implications for vaccination strategy in Canadian indigenous communities

BACKGROUND

Bacille Calmette-Guérin (BCG) vaccination against tuberculosis (TB) is widespread in high-TB-burden countries, however, BCG vaccination policies in low-burden countries vary. Considering the uncertainties surrounding BCG efficacy and the lower likelihood of TB exposure in low-incidence countries, most have discontinued mass vaccination, choosing instead a targeted vaccination strategy among high-risk groups. Given the increased risk of TB infection in Canadian Indigenous communities compared to the general Canadian population, these communities are a pertinent example of high-incidence groups in an otherwise low-burden country, warranting particular consideration regarding BCG vaccination strategy. This systematic review aims to synthesise and critically appraise the literature on BCG vaccination strategies in high-risk groups in low-incidence settings to provide policy considerations relevant to the Canadian Indigenous context.

METHODS

A literature search of the Medline and Embase databases was conducted, returning studies pertaining to BCG vaccine efficacy, TB incidence under specific vaccination policies, BCG-associated adverse events, and vaccination policy guidelines in low-burden countries. Study screening was tracked using the Covidence systematic review software (Veritas Health Innovation, Melbourne, Australia), and data pertaining to the above points of interest were extracted.

RESULTS

The final review included 49 studies, spanning 15 countries. Although almost all of these countries had implemented a form of mass or routine vaccination previously, 11 have since moved to targeted vaccination of selected risk groups, in most cases due to the low risk of infection among the general population and thus the high number of vaccinations needed to prevent one case in the context of low-incidence settings. Regarding identifying risk groups for targeted screening, community-based (rather than individual risk-factor-based) vaccination has been found to be beneficial in high-incidence communities within low-incidence countries, suggesting this approach may be beneficial in the Canadian Indigenous setting.

CONCLUSIONS

Community-based vaccination of high-incidence communities may be beneficial in the Canadian Indigenous context, however, where BCG vaccination is implemented, delivery strategies and potential barriers to achieving adequate coverage in this setting should be considered. Where an existing vaccination program is discontinued, it is crucial that an effective TB surveillance system is in place, and that case-finding, screening, and diagnostic efforts are strengthened in order to ensure adequate TB control. This is particularly relevant in Canadian Indigenous and other remote or under-served communities, where barriers to surveillance, screening, and diagnosis persist.

Evaluating a 24-year tuberculosis screening in first-grade elementary schoolers in a low-burden area

AIM

Early diagnosis of tuberculosis infection can significantly contribute to the control of the disease. The aim of the present study was to describe the tuberculin skin test (TST) trends over a 24-year period (1990-2013) and explore the value of universal tuberculosis screening in a low-burden area.

METHODS

All first graders that underwent TST during the 24-year study period (1990-2013) on the island of Crete, Greece, were retrospectively included in the study.

RESULTS

A total of 82 402 children (92.3% of Greek nationality; 51.0% male) underwent TST, of whom 335 (0.41%, 95% CI 0.37-0.46) were found to have positive TST while 0.27% of the study population had a TST between 5 and 9 mm. The tuberculin index declined significantly between 1990-1994 and 2010-2013 (0.67 vs 0.26; RR 2.73, 95% CI 1.82-4.09; p < 0.0001). Positive TST result was significantly higher in the immigrant than the native group (0.66% vs 0.24%; RR 3.76 95%, CI 2.89-4.84; p < 0.0001). In the last study years, 386 children (488 native; 153 immigrant) should be tested for one to be found TST positive.

CONCLUSION

Our findings question the massive tuberculin testing in low-burden areas and point to selective screening of high-risk groups.