境外输入性病例对疫情防控的影响——基于SEIDR传染病模型

 为探究新型冠状病毒肺炎疫情因全球跨境流动带给中国境内疫情防控的影响，根据经典传染病动力学模型，提出考虑了境外输入性病例的SEIDR传染病模型。模型将入境人员分为未经海关入境人员和通过海关入境人员，设计了“境内有疫情，境外无输入”“境内无疫情，境外有输入”“境内有疫情，境外有输入”等3种情形。通过计算各类情形下感染人数峰值和持续的时间范围，比较不同类型的入境方式对境内疫情的影响和对境内医疗资源造成的压力。根据研究结果，建议根据疫情风险程度和资源条件采取检测措施；对未经海关入境的人员严格防控，对通过海关入境人员进行闭环管理；动态调整入境隔离措施和隔离期，在保证境内外疫情防控的提前下逐步恢复国际交流；整合医疗资源，提高配置效率，缓解境内资源占用压力。

An infectious disease model considering the impact of imported cases on internal spread of COVID-19

The coronavirus disease 2019(COVID-19) pandemic spreads across borders with the frequent global population movement. To explore the impact of the COVID-19 pandemic on China's domestic epidemic prevention and control, based on the classical infectious disease dynamics model this paper proposes an infectious disease model that considers oversea imported cases. The model can simulate three situations:national pandemic without imported cases, no domestic cases with only imported cases, and domestic cases with international travellers entering simultaneously. By calculating the peak case number and range of infection spread duration in these situations, as well as the amount of medical resources invested, the model has shown the different results of impact of entry type on the domestic pandemic and different pressures on medical resources. Finally, the paper suggests that testing measures should be taken according to the degree of pandemic risk and resource conditions, that strict prevention and control should be applied to the people not entering through customs, and closed-loop management to the people entering through customs, that entry quarantine measures and quarantine periods should be dynamically adjusted and international exchanges should be gradually resumed in the context of ensuring domestic and overseas epidemic prevention and control in advance, and that it is necessary to integrate medical resources, improve allocation efficiency, and relieve the pressure of resource occupation.