Abstract:

Objective: To investigate the characteristics of tuberculin skin test (TST) reaction of freshmen enrolled in universities and high schools in Beijing from 2020 to 2022, and to provide basis for school tuberculosis prevention and control and epidemic situation. Methods: Based on the “Beijing New Student Tuberculosis Screening System” and the University New Student PPD Screening Registration Form report, the database of tuberculosis screening for new students enrolled in universities and high schools in Beijing was established, and 292486 new students enrolled in high schools and universities who had completed TST testing and retesting from 2020 to 2022 were selected as the survey objects. Among them, 159915 were newly admitted university students who underwent monitoring from 2020 to 2021, and 132571 were newly admitted high school students from 2021-2022. All the survey subjects underwent TST and completed retesting. Results: Of the subjects, 15.57% (45545/292486) had an average diameter of TST hard nodules ≥5 mm, 7.38% (21582/292486) had an average diameter of hard nodules ≥10 mm, and 2.94% (8599/292486) had an average diameter of hard nodules ≥15 mm. Among college freshmen, the positive rate in female students (9.27%, 6678/72038) was significantly higher than that in male students (8.93%, 7836/87708) based on the average diameter of hard nodules ≥10 mm, with a statistically significant difference (χ²=5.403, P=0.020). The positive rates of students from the western, central, and eastern regions were 10.95% (3757/34297), 10.15% (3642/35897), and 7.69% (6659/86580), respectively, with statistically significant differences (χ²=399.682, P<0.001). Taking the average diameter of hard nodules ≥5 mm as the positive standard, the positive rate of male students (17.56%, 15403/87708) was significantly higher than that of female students (17.03%, 12269/72038; χ²=7.769, P=0.005). Among high school freshmen, the positive rate of female students (5.62%, 3539/63018) was significantly higher than that of male students (5.06%, 3517/69553) based on the average diameter of hard nodules≥10 mm, with a statistically significant difference (χ²=20.523, P<0.001). The positive rate of patients with suspected symptoms of pulmonary tuberculosis was significantly higher than those without suspected symptoms of pulmonary tuberculosis (10.63% (17/160) vs. 5.32% (7039/132408), χ²=8.938, P=0.003). The positive rate of patients with close contact history of pulmonary tuberculosis (11.48%, 14/122) was higher than those without close contact history (4.76%, 5733/120501), and the difference was statistically significant (χ²=12.122, P<0.001). The positive rate of new students in urban six districts (5.70%, 4373/76713) was higher than that in non-urban six districts (4.80%, 2683/55858), and the difference was statistically significant (χ²=51.635, P<0.001). The overall tuberculosis detection rate among college freshmen was 33.96/100000 (129/379810), significantly higher than that of high school freshmen (15.09/100000 (20/132571)), with a statistically significant difference (χ²=12.047, P=0.001). Conclusion: The positive rate of TST and the detection rate of pulmonary tuberculosis of freshmen in Beijing’s university are higher than those of freshmen in senior high school. The infection rate of mycobacterium tuberculosis in female students, western student origin, students with suspected symptoms of pulmonary tuberculosis, and close contacts of pulmonary tuberculosis patients is relatively high, which suggests that the screening of pulmonary tuberculosis of freshmen in Beijing should be strengthened to improve the prevention and control of tuberculosis in schools.

Key words: Tuberculosis, pulmonary, Skin tests, Students