Longitudinal symptom transitions predict incident tuberculosis risk in serial active case finding

Tuberculosis (TB) screening often relies on cross-sectional symptom assessment. To determine the added value of longitudinal symptom monitoring, we conducted a prospective cohort study among 2,282 incarcerated men in Brazil. Every four months, participants were assessed for symptoms and incident TB (Xpert or culture positive). Compared to remaining asymptomatic, developing symptoms was associated with higher TB risk (aRR 2.31; 95% CI 1.55-3.43), strongest among those with prior radiographic abnormalities (aRR 2.49; 95% CI 1.56-3.97), while remaining symptomatic was not associated (aRR 1.27; 95% CI 0.72-2.24). Longitudinal symptom monitoring may enhance TB screening in high-risk settings, particularly in complement with radiography.