Zhang Siyuan, Liu Liran, Meng Qingxiang, Zhang Yixuan, Yang He, Xu Gang
School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China.
School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China.
Trop Med Infect Dis. 2023 Jun 30;8(7):349. doi: 10.3390/tropicalmed8070349.
COVID-19 has undergone multiple mutations, with the Omicron variant proving to be highly contagious and rapidly spreading across many countries. The United States was severely hit by the Omicron variant. However, it was still unclear how Omicron transferred across the United States. Here, we collected daily COVID-19 cases and deaths in each county from 1 December 2021 to 28 February 2022 as the Omicron wave. We adopted space-time scan statistics, the Hoover index, and trajectories of the epicenter to quantify spatiotemporal patterns of the Omicron wave of COVID-19. The results showed that the highest and earliest cluster was located in the Northeast. The Hoover index for both cases and deaths exhibited phases of rapid decline, slow decline, and relative stability, indicating a rapid spread of the Omicron wave across the country. The Hoover index for deaths was consistently higher than that for cases. The epicenter of cases and deaths shifted from the west to the east, then southwest. Nevertheless, cases were more widespread than deaths, with a lag in mortality data. This study uncovers the spatiotemporal patterns of Omicron transmission in the United States, and its underlying mechanisms deserve further exploration.
新冠病毒已发生多次变异，事实证明，奥密克戎变异毒株具有高度传染性，并在许多国家迅速传播。美国受到奥密克戎变异毒株的严重冲击。然而，奥密克戎变异毒株在美国境内是如何传播的仍不清楚。在此，我们收集了2021年12月1日至2022年2月28日各县每日的新冠病例和死亡数据，作为奥密克戎毒株传播高峰期的数据。我们采用时空扫描统计法、胡佛指数以及疫情震中轨迹来量化新冠病毒奥密克戎毒株传播高峰期的时空模式。结果显示，最早出现的最高发聚集区位于美国东北部。病例和死亡人数的胡佛指数均呈现出快速下降、缓慢下降和相对稳定的阶段，这表明奥密克戎毒株传播高峰期在全国范围内迅速蔓延。死亡人数的胡佛指数始终高于病例数的胡佛指数。病例和死亡的震中从西部转移到东部，然后又转移到西南部。尽管如此，病例的分布范围比死亡人数更广，死亡数据存在滞后性。本研究揭示了奥密克戎毒株在美国传播的时空模式，其潜在机制值得进一步探索。
