Abstract: Objective To analyze the epidemiological characteristics of index cases of pulmonary tuberculosis (TB) and their close contacts in schools in Xindu District, Chengdu, and to provide reference for improving school TB prevention and control strategies. Method Based on the individual case questionnaires of school TB index cases and on-site epidemiological investigation reports of close contacts in Xindu District, Chengdu from 2019 to 2024, the trend χ² test was used to analyze the annual change trend of the reported incidence rate of school TB; the descriptive epidemiological analysis method was adopted to explore the three-dimensional distribution characteristics (time, space, and population) of the cases; multivariate Logistic regression analysis was conducted to identify the influencing factors for the occurrence of strong positivity in the tuberculin skin test (TST) among close contacts. Result A total of 198 school TB cases were reported in Xindu District, Chengdu from 2019 to 2024, with an annual average reported incidence rate of 11.97 per 100 000, showing a continuous downward trend (χ²=14.674, P<0.05). Secondary vocational and technical schools had the highest annual average reported incidence rate (58.44/100 000), while colleges and universities had the largest number of cumulative reported cases (86 cases, accounting for 43.43%). The time of case report is mainly concentrated in March, April, September and November every year. Xindu Sub-district is a persistently high-incidence area for reported index cases. A total of 7,448 close contacts were identified during 2019-2024. Multivariate Logistic regression analysis showed that the risk factors for TST strong positivity in close contacts included: the index case being a student (OR=3.261, 95%CI: 2.112-5.006), the school type being junior high school (OR=4.178, 95%CI: 2.061-8.472), senior high school (OR=4.781, 95%CI: 2.338-9.776), secondary vocational and technical school (OR=3.094, 95%CI: 1.470-6.512), or college/university (OR=3.887, 95%CI: 1.980-7.629), as well as the index case having a positive etiological test result (OR=2.550, 95%CI: 1.605-4.051) or no etiological test result (OR=2.907, 95%CI: 1.693-4.993). Conclusion From 2019 to 2024, the reported incidence rate of pulmonary tuberculosis in schools in Xindu District, Chengdu showed an overall decreasing trend year by year. Risk factors for strong positive TST results among close contacts included the index case being a student, the school type (junior high school, senior high school, vocational and technical secondary school, or institution of higher education), and the index case being etiologically positive or having no etiological test results. It is recommended to implement classified school management and implement preventive treatment for high-risk groups to achieve precise prevention and control of pulmonary tuberculosis in schools.

Key words: Pulmonary tuberculosis, Schools/Xindu District, Index cases, Close contacts, Tuberculin Skin Test, Screening