Analysis of the Tuberculosis Latent Infection Status and Influencing Factors in Close Contacts of Patients with Bacteriologically Confirmed Pulmonary Tuberculosis

Objective: To investigate latent tuberculosis infection（LTBI）and associated risk factors among close contacts of positive pulmonary tuberculosis patients in JIngAn District，Shanghai.Provide a basis and reference for preventive intervention strategies and policies among close contacts in the future. Methods: The study subjects were pulmonary tuberculosis patients with bacteriological positive and their close contacts registered to test for Mycobacterium tuberculosis infection by intern gamma release assay(IGRA) in Jing'an District, Shanghai from October 2022 to October 2023. The influence factors of LTBI were analyzed by x² test and binary logistic regression model. Results: A total of 112 close contacts were included, of which 30 (26.79%) were male and 82 (73.21%) were female; the age range was 1 to 86 years, with a median (Quartile) of 47.50 (32.25 61.00) years. LTBI infection rate was 21.43% (24/112), and the incidence of pulmonary tuberculosis was 2.68% (3/112). Univariate analysis results show that the sputum smear results of the index cases, whether the close contacts are immediate family members, whether they live together and whether protective measures are taken affect the incidence of tuberculosis latent infection in close contacts of patients with bacteriological positive pulmonary tuberculosis, and the difference statistically significant (P < 0.05). The risk of latent infection in close contacts of the index case with a positive sputum smear is 6.5 times higher than those with a negativeutum smear (OR=6.498, 9%CI: 1.82～23.25, P=0.004). Conclusion: The infection rate of LTBI in close contacts of pulmonary tuberculosis patients with pathogenic bacteria positive in Shanghai Jing'an District was relatively high especially for close contacts of pulmonary tuberculosis patients with positive sputum smear, the risk of LTBI infection was more prominent, and it was necessary to improve the tracking management of tuberculosis infection detection and follow-up reexamination.