Tuberculosis exposure in a German childcare setting: contact investigation findings and considerations for preventive screening

Purpose Tuberculosis (TB) exposure in early childhood settings presents major public health challenges because of the vulnerability of young children and the complexity of contact investigations. We report findings from a large TB contact investigation following delayed diagnosis and prolonged infectiousness of a young adult in a childcare training setting. Methods Screening yields were calculated and public health workload prospectively documented. Additionally, the predictive performance of hypothetical screening pathways was explored in an illustrative low-prevalence scenario using Bayes’ theorem with literature-based estimates of sensitivity and specificity for chest X-ray (CXR) and interferon-gamma release assay (IGRA). Parameter uncertainty was assessed using Monte Carlo simulation. Results The index case, a young adult from a TB high-incidence country training as an early childhood educator, reported symptoms for about seven months prior to diagnosis. Across multiple settings, 183 contacts were identified, including 116 children (71 aged < 5 years). One child < 5 years of age was treated for active pulmonary TB. Among eligible children, 45/87 (52%) received prophylactic therapy. The overall investigation yield was 3.28% (95% CI, 1.21–7.00). Among adults, latent TB yield was 7.46% (95% CI, 2.47–16.56). Public health management required nearly 800 working hours. The illustrative model demonstrated limited predictive performance of hypothetical screening pathways in low-prevalence settings. Conclusions TB exposure in childcare settings requires substantial public health resource utilization and cannot be reliably prevented through screening alone. Effective TB control depends on timely diagnosis, rapid contact investigation, and coordinated public health action.