Background: 

Understanding geographic patterns of HIV transmission is critical to designing effective interventions. We characterized geographic proximity by transmission risk and urban–rural characteristics among people with closely related HIV strains suggestive of potential transmission relationships.

Methods: 

We analyzed US National HIV Surveillance System data of people diagnosed between 2010 and 2016 with a reported HIV-1 partial polymerase nucleotide sequence. We used HIV TRAnsmission Cluster Engine (HIV-TRACE) to identify sequences linked at a genetic distance of ≤0.5%. For each linked person, we assessed median distances between counties of residence at diagnosis by transmission category and urban–rural classification, weighting observations to account for persons with multiple linked sequences.

Results: 

There were 24,743 persons with viral sequence linkages to at least one other person included in this analysis. Overall, half (50.9%) of persons with linked viral sequences resided in different counties, and the median distance from persons with linked viruses was 11 km/7 miles [interquartile range (IQR), 0–145 km/90 miles]. Median distances were highest for men who have sex with men (MSM: 14 km/9 miles; IQR, 0–179 km/111 miles) and MSM who inject drugs, and median distances increased with increasing rurality (large central metro: 0 km/miles; IQR, 0–83 km/52 miles; nonmetro: 103 km/64 miles; IQR, 40 km/25 miles–316 km/196 miles).

Conclusion: 

Transmission networks in the United States involving MSM, MSM who inject drugs, or persons living in small metro and nonmetro counties may be more geographically dispersed, highlighting the importance of coordinated health department efforts for comprehensive follow-up and linkage to care.

中文翻译：

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美国HIV传播网络的地理分布

背景： 

了解艾滋病毒传播的地理模式对于设计有效的干预措施至关重要。我们通过传播风险和具有密切关系的HIV菌株人群之间的城乡特征来描述地理上的邻近性，这表明潜在的传播关系。

方法： 

我们分析了2010年至2016年之间据报告的HIV-1部分聚合酶核苷酸序列诊断出的人群的美国国家HIV监测系统数据。我们使用HIV传输簇引擎（HIV-TRACE）来识别遗传距离≤0.5％的序列。对于每个有联系的人，我们通过传播类别和城乡分类评估了诊断时居住县之间的中位距离，并对观察结果进行加权，以说明具有多个有联系序列的人。

结果： 

该分析中有24,743个人与至少一个其他人具有病毒序列连锁。总体上，一半（50.9％）具有连锁病毒序列的人居住在不同的县，距带有连锁病毒的人的中位距离为11 km / 7英里[四分位间距（IQR），0-145公里/ 90英里]。与男性发生性关系的男性（MSM：14 km / 9英里； IQR，0-197 km / 111英里）和注射毒品的MSM的中位距离最高，并且中位距离随着农村人口的增加而增加（大型中央地铁：0 km /英里； IQR，0-83公里/ 52英里；非地铁：103 km / 64英里； IQR，40 km / 25英里-316 km / 196英里）。

结论： 

在美国，涉及MSM，注射毒品的MSM或居住在小城市和非都市县的人员的传播网络可能在地理上更加分散，突出了卫生部门协调努力以进行全面跟进和与护理联系的重要性。