Tuberculin skin test results among student close contacts with pulmonary tuberculosis

Objective: To investigate the status of tuberculin skin test (TST) results and the influencing factors among student close contacts with pulmonary tuberculosis, so as to provide the evidence for developing prevention and control strategies for pulmonary tuberculosis among students. Methods: The students aged 15 years and above who had close contact with pulmonary tuberculosis cases in Yuecheng District, Shaoxing City, Zhejiang Province, from October 2016 to December 2023 were recruited and investigated using questionnaires and TST to collect demographic information, contact history, and TST results. The influencing factors for TST positivity among student close contacts with pulmonary tuberculosis were analyzed using a multivariable logistic regression model. Results: A total of 5 507 student close contacts were investigated, including 2 982 males and 2 525 females, with a male-to-female ratio of 1.18∶1. The mean age was (19.10±1.71) years. Among them, 397 (7.21%) were technical secondary school students, 766 (13.91%) were senior high school students, 2 556 (46.41%) were junior college students, and 1 788 (32.47%) were college students or above. A total of 958 students tested positive for TST, with a positivity rate of 17.40%. The rates of general positivity, moderate positivity, and strong positivity were 10.53%, 4.98% and 1.89%, respectively. Multivariable logistic regression analysis showed that senior high school students (OR=1.473, 95%CI: 1.009-2.152) and junior college students (OR=1.467, 95%CI: 1.074-2.005), as well as those with an exposure-to-screening interval of ≥46 days (46-<61 days, OR=2.043, 95%CI: 1.478-2.826; ≥61 days, OR=1.291, 95%CI: 1.018-1.637) had a higher risk of TST positivity. Female student close contacts had a lower risk of TST positivity (OR=0.753, 95%CI: 0.649-0.873). Conclusion: The TST positivity rate was relatively high, and gender, school type, and exposure-to-screening interval were influencing factors for TST positivity among student close contacts with pulmonary tuberculosis.