[Analysis of the characteristics of HIV-1 molecular transmission network among people aged 50 years and above in Pengzhou city of Sichuan province].

Objective: To describe the characteristics of molecular transmission network of newly diagnosed HIV-1 infected patients, analyze their risk factors related to network access and provide a scientific basis for precise prevention of HIV infection. Methods: For 340 blood samples collected from confirmed HIV-1 infection cases aged ≥50 years in Pengzhou city of Sichuan province from April 2019 to August 2021, nested PCR amplification was used to amplify, clean up and splice clips the pol gene region. The phylogenetic tree was constructed by multi-sequence comparison to distinguish subtypes, and the pairwise genetic distance was calculated. When the genetic distance threshold was 0.90%, the number of clusters was the largest (41), and the molecular transmission network was constructed.The χ2 test and logistic regression analysis were performed.The software SPSS 19.0 was used for statistical analysis. Results: A total of 340 samples were successfully amplified (97.06%, 330/340) in 330 samples. 6 HIV-1 subtypes identified, including:CRF01_AE(56.67%,187/330), CRF07_BC(27.88%,92/330), B(11.21%,37/330), CRF08_BC(3.33%,11/330), CRF55_01B(0.61%,2/330) and C(0.30%,1/330).The network entry rate was 58.79% (194/330).The results of logistic regression analysis of the risk factors of HIV-1 molecular transmission network in the research subjects showed that compared with illiteracy, junior high school (OR=0.35, 95%CI:0.13-0.97) and high school/technical secondary school (OR=0.14, 95%CI: 0.02-0.97) had lower possibility of network entry. Compared with farmers, unknown occupations (OR=0.40,95%CI: 0.17-0.95) are less likely to enter the network .Compared with CRF01_AE, CRF07_BC (OR=0.20, 95%CI: 0.11-0.35) and CRF08_BC subtype (OR=0.09, 95%CI: 0.02-0.45) were less likely to enter the network. Conclusions: The sources of AIDS transmission among middle-aged and elderly people of rural areas are diversified in Pengzhou city of Sichuan province. AIDS intervention should focus on middle-aged and elderly farmers with low educational level, and strengthen detection and traceability investigation.目的： 分析HIV-1感染者分子传播网络特征及其传播的相关危险因素，为HIV-1精准预防提供依据。 方法： 对2019年4月至2021年8月四川省彭州市新报告≥50岁HIV感染者的340份血样，采用巢式PCR扩增法对pol基因区进行扩增、清理、拼接剪辑，多序列对比构建系统进化树区分亚型，计算成对基因距离，在基因距离阈值为0.90%时成簇数最多（41个），构建分子传播网络。分析HIV分子传播网络特征及入网危险因素，进行χ2检验及logistic回归分析。采用SPSS 19.0软件进行统计学分析。 结果： 340份样本中，扩增成功330份（97.06%，330/340）。确定6种HIV-1亚型，包括CRF01_AE（56.67%，187/330）、CRF07_BC（27.88%，92/330）、B（11.21%，37/330）、CRF08_BC（3.33%，11/330）、CRF55_01B（0.61%，2/330）和C（0.30%，1/330）。入网率为58.79%（194/330），研究对象HIV-1分子传播网络的入网危险因素logistic回归分析结果显示，相比于文盲，初中（OR=0.35，95%CI：0.13~0.97）与高中/中专文化程度（OR=0.14，95%CI：0.02~0.97）的入网可能性较低；相比于农民，职业不详（OR=0.40，95%CI：0.17~0.95）的入网可能性较低；相比于CRF01_AE亚型，CRF07_BC（OR=0.20，95%CI：0.11~0.35）和CRF08_BC亚型（OR=0.09，95%CI：0.02~0.45）的入网可能性较低。 结论： 四川省彭州市农村地区中老年群体中艾滋病传播来源多元化，艾滋病干预工作应重点定位于低文化程度的中老年农民，同时加强检测与溯源调查。.