Analysis of the Spatio-Temporal Characteristics and Transmission Path of COVID-19 Cluster Cases in Zhuhai
【Abstract in Chinese】 利用珠海市卫生健康局公开发布的98例新型冠状病毒肺炎病例流行病学调查数据，通过26个疫情聚集单元的时空特征分析和4类典型传播路径的案例剖析，深入探讨了珠海市新型冠状病毒肺炎聚集发生的时空规律和传播路径。结果表明：1）珠海的疫情发展与武汉的人口流动与管控密切相关，由于管控及时，目前仍以疫源区直接输入和家庭聚集扩散为主要传播方式，在有限范围内扩散。2）存在输入一代家庭聚集传播、输入一代非家庭聚集传播、输入二代家庭聚集传播、输入二代非家庭聚集传播4种不同的传播路径，且以第一种为主要方式，但非家庭聚集传播的路径复杂，应加强流行病学调查和防控。3）对输入性病例从输入到发病的滞后周期以及聚集单元最长发病时间间隔来看，有少部分病例或携带者可以突破14 d限制，应警惕目前普遍采用的14 d隔离措施可能存在的风险。
【Abstract】 On the eve of the Spring Festival in 2020, an epidemic of COVID-19 broke out in Wuhan and spread across the country in a short time through population movements, posing a huge threat to Zhuhai and other large cities with frequent population movements. Based on the epidemiological survey data of 98 cases of COVID-19 published by Zhuhai Municipal Health Bureau, the spatial and temporal characteristics of 26 epidemic clusters and the case analysis of 4 types of typical transmission routes were analyzed, the spatial and temporal patterns and transmission routes of pneumonia in Zhuhai City were discussed in this paper. The results showed that: 1) the epidemic situation in Zhuhai was related to the population flow and control in Wuhan. Due to the timely management and control, the epidemic situation was still spread in a limited range mainly by the direct import of the focus area and the gathering and spreading of families. 2) there are four different transmission paths, imported family cluster unit, imported non-family cluster unit, imported and local family cluster unit, imported and local non-family cluster unit, and the first one is the main one, however, the path of non-family cluster transmission is complex, so we should strengthen epidemiological investigation and prevention and control. 3) for imported cases, the LAG period from importation to onset and the longest time interval between onset of the cluster unit, a small number of cases or carriers can break the 14-day limit, caution should be exercised regarding the possible risks of the 14-day isolation measure currently in general use. Based on the findings of this study, the following recommendations are made for the prevention and control of COVID-19: 1) it is necessary to fully estimate the risk of epidemic situation that may be brought about by the "back-to-work tide" , strengthen the study of epidemiology, actively explore the spatio-temporal law of population flow and epidemic situation spread, and precisely prevent and control according to the scientific law, to stop the virus in its tracks. 2) it is necessary to persist in the prevention and control of the influx of people from Hubei and other high-risk epidemic areas. The 14-day quarantine currently in place throughout the country is effective for the vast majority of cases or carriers of the virus, however, according to the results of the study on the LAG period from input to onset and the longest time interval between onset of cluster, there are still a few cases or carriers who can break through the 14-day limit, it is suggested that the isolation time should be prolonged according to the study of the incubation period up to 24 days by Academician Zhong. 3) strengthen the combination of epidemiological investigation and geographic information technology, timely track the occurrence and spread of the epidemic, accurately excavate the activities of high-risk groups, trace back to the source, accurate prevention and control. In short, for a major public health crisis like the outbreak of COVID-19, its emergency management and control often involves many scientific fields, such as medical field, geographic information science, computer and information science, psychology and behavior science, timely and effective prevention and control measures need to rely on multi-disciplinary joint exploration.
【Key words】 COVID-19； Zhuhai； aggregation； spatio-temporal characteristics； transmission path；