Objective To investigate the status and influencing factors of latent tuberculosis infection (LTBI) among close contacts of patients with bacteriologically confirmed pulmonary tuberculosis in Jing’an District, Shanghai, and to provide scientific evidence for the development of tuberculosis infection testing and preventive intervention strategies for close contacts of bacteriologically positive patients.

Methods From October 2022 to October 2023, patients with bacteriological confirmed pulmonary tuberculosis registered in Jing’an District, Shanghai, and their close contacts were enrolled as the research subjects. The close contacts were screened for tuberculosis infection using the interferon-γ release assay (IGRA). The chi-square test and binary logistic regression model were used to analyze factors influencing LTBI.

Results A total of 112 close contacts were included, of whom 30 (26.79%) were male and 82 (73.21%) were female. The age ranged from 1 to 86 years, with a median (25th, 75th percentiles) of 47.50 (32.25, 61.00) years. The infection rate of LTBI was 21.43% (24/112), and the incidence of active pulmonary tuberculosis was 2.68% (3/112). Univariate analyses showed that a positive sputum smear of the index case, being a direct relative of the index case, co-living, and not wearing a mask were significantly associated with LTBI (all P<0.05). Multivariate logistic regression analyses showed that the risk of latent infection in close contacts of the index case with a positive sputum smear was 6.50 times higher than in those with a negative sputum smear (95%CI: 1.82‒23.25, P=0.004).

Conclusion The infection rate of LTBI in close contacts of patients with bacteriologically confirmed pulmonary tuberculosis in Jing’an District, Shanghai, is relatively high, and close contacts of sputum smear-positive patients face an even higher risk of infection. Therefore, tuberculosis infection screening and follow-up management should be strengthened for this population.