Abstract:

Objective: To analyze tuberculosis (TB) infection and influencing factors in household close contacts of active pulmonary TB patients who studies in local schools (HCCSs). Methods: All HCCSs registered in Baoying County and Zhangjiagang City in Jiangsu Province, Yidu City in Hubei Province, Pengshui County in Chongqing City, and Zhaoyang District of Zhaotong City in Yunnan Province from January 1 to December 31 in 2021 were included into this investigation. Tuberculin skin test (TST) was carried out and demographic characteristics were collected for every participant, and demographic and diagnostic information of their index cases were also collected from Chinese Tuberculosis Information Management System (TBIMS), by which factors associated with TB infection among HCCSs were analyzed. Results: Totally 686 HCCSs were included for 477 active pulmonary TB patients. Overall acceptance rate of TST for these HCCSs was 92.27% (633/686).The differences of TST acceptance rates between counties/districts were statistically significant (χ²=57.781, P<0.001), with the highest rate in Baoying County (100.00%, 35/35). The overall TB infection rate and strong positive rate of TST among HCCSs were 14.85% (94/633; 95%CI: 11.85%-17.85%) and 5.06% (32/633), respectively, with statistically significant differences between counties/districts (χ²=35.800, P<0.001;Fisher exact probability method,P=0.029). The results of univariate analysis showed that HCCS aged 15 years old and above ((23.47% (23/98); 95%CI:13.88%-33.06%)), studying in high schools and colleges ((26.09% (18/69); 95%CI:14.04%-38.14%)), living in Yidu City ((33.33% (28/84); 95%CI:20.99%-45.68%)), and contacting with TB patients with diagnosis delay ((18.37% (52/283); 95%CI:13.38%-23.37%)) had a higher prevalence rate of TB infection. In multifactorial logistic regression, diagnosis delay of index cases was founded to be associated with TB infection of HCCSs. After adjusting confounding factors, HCCSs contacted with TB patients with diagnosis delay had a higher TB infection risk than those contacted with TB patients without diagnosis delay, with OR (95%CI) being 1.586 (1.016-2.476). Conclusion: High TB infection rate exists in HCCSs, especially those contacted with active pulmonary TB patients with diagnosis delay. Our study showed timely screening and following intervention is necessary for HCCSs.

Key words: Tuberculosis, pulmonary, Student, Contact tracing, Tuberculin skin test, Factor analysis,statistical