Supplementary Material for: Tuberculosis case detection and guideline adherence among child contacts in Switzerland: a retrospective observational study.

Background: Children exposed to a tuberculosis (TB) index case are at high risk of TB infection and disease. The aim of this study was to describe the proportion of child contacts who developed TB infection or disease after exposure, to assess the diagnostic pathways and adherence to current guidelines. Method: Retrospective observational study including children ≤ 16 years of age who had contact to a TB index case between January 2019 and July 2021. Analysis was stratified by age groups 0 to 4, 5 to 11 and 12 to 16 years. Results: Of 401 TB-exposed children, data were available for 380 (95%). Of those, 7 (2%) were diagnosed with TB disease and 35 (8%) with TB infection. We identified several deviations in the procedures compared to Swiss guidelines: In the children aged 0 to 4 years, only 82% were examined with an immunodiagnostic test or a chest radiography within two weeks after last contact. Recommended prophylactic treatment was prescribed in 66% of the children only. In the children aged 5 to 11 years, 64% were tested with an immunodiagnostic test in a first examination and 75% in a second examination, two weeks and two months after last contact, respectively. Conclusions: Contact investigations of children exposed to a TB index case identified a significant proportion of children with TB infection and disease in a low TB incidence setting. We observed significant deviations from the guidelines in the contact investigations suggesting the need for improved implementation.