本文筛查和随访结核密切接触者的潜伏感染情况和发病情况，并分析了相关的影响因素。首先，回顾性分析了2012年3月—2019年8月在无锡市第五人民医院结核科住院的活动性肺结核患者的临床资料，并随访了其中进行过γ干扰素释放试验(interferon-γ release assay, IGRA)的密切接触者。7年共完整随访到39例活动性肺结核患者及其74例密切接触者，74例密切接触者中27例IGRA阳性(36.5%)，47例IGRA阴性(63.5%)，且IGRA阳性密切接触者中无一例进展为活动性结核。单因素分析结果提示，IGRA阳性密接组和IGRA阴性密接组在吸烟 (3/27 vs 0/47，P＝0.045)、与结核患者接触时间 >5 h/d (22/27 vs 23/47，P＝0.007)、同屋居住 (23/27 vs 20/47，P＝0.001) 3方面的差异具有统计学意义。进一步比较发现，较于IGRA阴性密接组，IGRA阳性密接组接触的活动性肺结核患者痰涂片结核菌的负荷量更高(P＝0.019)。多因素分析结果则显示，肺结核患者痰涂片结核菌量能够显著影响密切接触者的IGRA结果，痰结核菌量高的活动性肺结核密切接触者更容易出现IGRA阳性。

This paper screened and followed up close contacts of active pulmonary tuberculosis to understand the latent infection and morbidity of close contacts and analyze related factors. It retrospectively analyzed the clinical data of patients with active pulmonary tuberculosis hospitalized in the tuberculosis ward of Wuxi No.5 People’s Hospital from March 2012 to August 2019, and analyzed and followed up the close contacts who had conducted the interferon-γ release assay (IGRA). A total of 39 active pulmonary tuberculosis patients under initial treatment and 74 close contacts were included in the analysis. Of all the 74 close contacts, 27 contacts were IGRA positive (36.5%) and 47 contacts were IGRA negative (63.5%). None of the 27 IGRA-positive close contacts progressed to active tuberculosis, but the differences between the two groups in terms of smoking (3/27 vs 0/47, P＝0.045), contact time with tuberculosis patients >5 h/d (22/27 vs 23 /47, P＝0.007), living in the same house (23/27 vs 20/47, P＝0.001) were statistically significant. Active tuberculosis patients corresponding to IGRA-positive close contacts and those corresponding to IGRA-negative close contacts were further compared, respectively, which found that the active TB patients corresponding to the IGRA positive group had more sputum smear tuberculosis bacteria load than that of the IGRA negative group (P＝0.019). Multivariate analysis showed that the amount of tuberculosis bacteria in sputum smear of tuberculosis patients was a significant factor influencing IGRA results of their close contacts. Close contacts of active pulmonary tuberculosis with higher sputum tuberculosis load are more likely to be IGRA positive.