Incidence and predictors of TB infection among children and adolescents in the SONET study

BACKGROUND Data are needed to guide TB prevention and case finding for children and adolescents. In this study, we hypothesised that risk factors for incident TB infection would change with age as young people spend more time outside the household, and the relative contribution of the household would therefore be low. METHODS We employed a longitudinal TB immunoreactivity survey in rural southwestern Uganda (ages 1-17 years). Our objectives were to 1) characterise overall and age-specific incidence and predictors of TB infection among children and adolescents and 2) estimate proportion of incident TB infections attributable to a household case. QuantiFERON (QFT) tests were used to test for TB infection, at baseline and at follow-up among participants who were QFT-negative at baseline. RESULTS Between June 2023 and September 2024, 3,145/4,707 (66.8%) eligible participants had a follow-up QFT. Estimated cumulative 1-year incidence of TB infection was 2.1% (95% confidence interval: 1.8%-4.1%), increasing with age. Household factors (alcohol use and outmigration) were predictive for children and community factors (participant-mobility and boarding school attendance) for adolescents. Household TB contact was predictive across age groups, but the relative contribution was low. CONCLUSION Our data reinforce the need for non-household, age-specific active case-finding programmes among young people. .