Objective:

To quantify tuberculosis (TB) burden, evaluate screening uptake and treatment initiation, and examine time from screening to treatment among migrant and asylum-seeking children and adolescents attending a targeted screening service in Scotland.

Approach:

• Study Design: A retrospective observational study using routinely collected clinical data.
• Setting: A UK health service in which TB screening was routinely offered to migrant children and adolescents.
• Participants: Children and adolescents assessed for TB screening during the study period; diagnostic outcomes were available for those screened.
• Data Collection: Clinical records provided demographic characteristics, screening outcomes, treatment initiation, and time from screening to treatment initiation.
• Outcomes: Primary outcomes were the prevalence of latent TB infection (LTBI) and active TB. Secondary outcomes included screening uptake, treatment initiation, and time to treatment initiation.
• Statistical Analysis: Descriptive statistics summarized cohort characteristics and prevalence. Associations with LTBI positivity were explored using Fisher exact, Mann–Whitney U, and, where appropriate, Firth penalized logistic regression analyses. Because few TB-positive outcomes occurred, analyses were exploratory and univariable.

Key Findings:

• Of 131 individuals assessed, 117 (89.3%) underwent TB screening.
• LTBI was identified in 13 of 117 screened participants (11.1%), and active pulmonary or disseminated TB was identified in 2 (1.7%).
• Overall, 15 of 117 screened participants (12.8%) had latent or active TB.
• Twelve of the 15 TB-positive participants originated from WHO high-incidence countries; 3 originated from medium- or low-incidence countries.
• Treatment was initiated in 14 of 15 identified cases (93.3%). The remaining participant was undergoing further investigation at data collection and subsequently began treatment.
• Median time from screening to treatment initiation was 35 days. Five of 13 LTBI cases (38.5%) began treatment within 28 days, whereas 3 (23.1%) experienced intervals exceeding 90 days.
• No assessed variable was significantly associated with LTBI positivity after correction for multiple comparisons.

Interpretation:

Targeted screening achieved high uptake and identified a substantial burden of latent and active TB within this migrant and asylum-seeking population in a low-incidence setting. High treatment initiation indicated strong engagement with care, although treatment timing varied. Identifying cases among participants from medium- or low-incidence countries suggests that country-of-origin incidence thresholds alone may not capture all relevant TB risk, particularly when migration-related exposures are considered. These findings are exploratory and should not be interpreted as establishing causal risk factors or the effectiveness of a screening intervention.

Limitations:

• The relatively small sample and limited number of TB-positive cases restricted statistical power, prevented causal inference, and limited analyses to exploratory univariable comparisons.
• The study was conducted within a single screening service, which may limit generalizability to other populations, settings, and healthcare systems.
• Fourteen individuals declined screening or were not screened for operational reasons, leaving their TB status unknown and potentially underestimating prevalence.
• BCG scar documentation was missing for 72 of 131 participants.
• Routinely collected records lacked detailed information on migration routes, travel duration, transit conditions, camp residence, and previous TB exposure.
• Country-level WHO incidence classifications may not reflect regional, community, or individual variation in exposure risk.

Conclusion:

Migrant and asylum-seeking children and adolescents attending this targeted service had a substantial burden of latent and active TB. Screening uptake and treatment initiation were high, although treatment intervals varied and some cases occurred among participants from countries not classified as high incidence. Larger multisite studies are needed to confirm these findings, evaluate targeted screening across settings, and clarify how migration-related exposures influence TB risk and care pathways.