Objective: To evaluate the exported risk of COVID-19 from Hubei Province and the imported risk in various provinces across China. Methods: Data of reported COVID-19 cases and Baidu Migration Indexin all provinces of the country as of February 14, 2020 were collected. The correlation analysis between cumulative number of reported cases and the migration index from Hubei was performed, and the imported risks from Hubei to different provinces across China were further evaluated. Results: A total of 49 970 confirmed cases were reported nationwide, of which 37 884 were in Hubei Province. The average daily migration index from Hubei to other provinces was 312.09, Wuhan and other cities in Hubei were 117.95 and 194.16, respectively. The cumulative COVID-19 cases of provinces was positively correlated with the migration index derived from Hubei Province, also in Wuhan and other cities in Hubei, with correlation coefficients of 0.84, 0.84, and 0.81. In linear model, population migration from Hubei Province, Wuhan and other cities in Hubei account for 71.2%, 70.1%, and 66.3% of the variation, respectively. The period of high exported risk from Hubei occurred before January 27, of which the risks before January 23 mainly came from Wuhan, and then mainly from other cities in Hubei. Hunan Province, Henan Province and Guangdong Province ranked the top three in terms of cumulative imported risk (the cumulative risk indices were 58.61, 54.75 and 49.62 respectively). Conclusion: The epidemic in each province was mainly caused by the importation of Hubei Province. Taking measures such as restricting the migration of population in Hubei Province and strengthening quarantine measures for immigrants from Hubei Province may greatly reduce the risk of continued spread of the epidemic.
目的： 评估湖北新型冠状病毒肺炎的疫情输出风险及其他各省从湖北输入疫情的风险。 方法： 获取截至2020年2月14日我国各省报告病例数（不含临床诊断病例；不含中国香港、澳门和台湾数据）和百度迁徙指数，对各省累计报告病例数和湖北迁出指数进行相关分析，评估湖北疫情输出风险和其他省疫情输入风险。 结果： 全国累计报告确诊病例49 970例，其中湖北37 884例。湖北平均每天迁出至其他省的指数为312.09，武汉和湖北其他市分别为117.95和194.16。各省累计报告病例数与湖北、武汉及湖北其他市迁出至各省的人口迁徙指数均成正相关，相关系数分别为0.84、0.84和0.81；湖北、武汉及湖北其他市人口迁出分别可解释线性模型71.2%、70.1%和66.3%的变异。湖北高输出风险时间集中在1月27日前，其中1月23日前的疫情输出风险主要来源于武汉，之后主要来源于湖北其他市。疫情输入风险排前3位的是湖南、河南和广东，累计风险指数分别为58.61，54.75和49.62。 结论： 我国各省疫情主要由湖北输入引起，湖北限制人口流出、各省加强对湖北省迁入人员的检疫，可以较大程度降低各省（除湖北）疫情持续传播风险。.
Keywords: COVID-19; Population migration; Risk assessment.