Latent Infection Freshmen Tracking for Tuberculosis

The goal of this study is to learn whether taking short-course preventive treatment in high school and college freshmen with strong positive tuberculosis (TB) skin tests can safely and effectively protect them from developing active TB over a 3-to-4-years period. Main question: Does taking short-course preventive treatment reduce the risk of active TB in freshmen who have strong positive TB skin tests? All freshmen across 26 schools in Meishan City, Sichuan Province, China were screened for TB. Among them, the students with strong positive skin tests (indicating latent TB infection) and no active disease entered the study. Students voluntarily chose to either take a 3-month short-course preventive treatment under campus medical supervision or receive routine health observation without medication. Researchers tracked all participants for 3 to 4 years to monitor who developed active TB and evaluate the treatment's safety and effectiveness.

Inclusion Criteria: * Matriculating freshmen aged 14-24 years enrolled across 26 participating educational institutions * Completion of baseline tuberculosis screening, including systematic symptom screening, digital chest radiography, and tuberculin skin test (TST) * Target cohort requirement: TST strong reactivity (induration ≥15 mm or severe local reactions such as blisters, necrosis, or lymphangitis) with active TB ruled out at baseline * Control cohort requirement: TST induration \