Mycobacterium tuberculosis transmission among child and adolescent contacts of people with pulmonary tuberculosis in Brazil: a multi-center prospective cohort study.
Luciana Sobral, María B Arriaga, Alexandra B Souza, Beatriz Barreto-Duarte, Beatriz S Garcia-Rosa, Catarina D Fernandes, Artur T L Queiroz, Michael S Rocha, et al. (24 authors)
BMC infectious diseases · 2025-12
Abstract
BACKGROUND: Children who are contacts of individuals with active pulmonary tuberculosis (PTB) are at risk of acquiringinfection (TBI). We evaluated the determinants of TBI in child and adolescent contacts.
METHODS: Pediatric (≤ 18 years old) close contacts of PTB patients enrolled in a multi-center Brazilian observational cohort were followed up to 6 months. Clinical evaluation, radiographic examination, and interferon gamma release assay (IGRA) were performed. Positive IGRA result at baseline or month 6 (IGRA-conversion) was considered an indicator of TBI. Multivariable mixed-effects logistic regressions were performed to identify factors associated with TBI.
RESULTS: Among 562 close contacts enrolled, 171 (30.4%) had a positive IGRA at baseline, and 37 (9.5%) converted at month 6. Positive AFB, persistent cough and cavity on chest X-ray of TB index were independently associated with a positive IGRA result at baseline. IGRA-conversion was independently associated with older age among contacts and chest X-ray cavitations in the index cases. Contacts ≥ 15.9 years old had 3.4 (95%CI: 1.49–7.78, = 0.004) adjusted odds ratio of IGRA-conversion than those < 15.9 years old.
CONCLUSION: Among pediatric close TB contacts, the prevalence of IGRA positivity increased with age. Older children have substantially higher susceptibility to TBI upon exposure.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-025-12268-5.