Liu Feng, Li Xin, Zhu Gaofeng
Key Laboratory of Remote Sensing of Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
National Tibetan Plateau Data Center, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China.
Sci Bull (Beijing). 2020 Aug 15;65(15):1297-1305. doi: 10.1016/j.scib.2020.04.043. Epub 2020 May 5.
Traditional compartmental models such as SIR (susceptible, infected, recovered) assume that the epidemic transmits in a homogeneous population, but the real contact patterns in epidemics are heterogeneous. Employing a more realistic model that considers heterogeneous contact is consequently necessary. Here, we use a contact network to reconstruct unprotected, protected contact, and airborne spread to simulate the two-stages outbreak of COVID-19 (coronavirus disease 2019) on the "Diamond Princess" cruise ship. We employ Bayesian inference and Metropolis-Hastings sampling to estimate the model parameters and quantify the uncertainties by the ensemble simulation technique. During the early epidemic with intensive social contacts, the results reveal that the average transmissibility was 0.026 and the basic reproductive number was 6.94, triple that in the WHO report, indicating that all people would be infected in one month. The and decreased to 0.0007 and 0.2 when quarantine was implemented. The reconstruction suggests that diluting the airborne virus concentration in closed settings is useful in addition to isolation, and high-risk susceptible should follow rigorous prevention measures in case exposed. This study can provide useful implications for control and prevention measures for the other cruise ships and closed settings.
传统的分区模型，如SIR（易感、感染、康复）模型，假定疫情在同质人群中传播，但疫情中的实际接触模式是异质的。因此，采用一个考虑异质接触的更现实模型是必要的。在此，我们使用一个接触网络来重构无保护接触、有保护接触以及空气传播，以模拟新冠病毒病（COVID-19）在“钻石公主”号游轮上的两阶段爆发。我们采用贝叶斯推断和梅特罗波利斯-黑斯廷斯抽样来估计模型参数，并通过系综模拟技术量化不确定性。在早期社交接触密集的疫情期间，结果显示平均传播率为0.026，基本再生数为6.94，是世界卫生组织报告中的三倍，这表明所有人将在一个月内被感染。实施隔离后，传播率和基本再生数降至0.0007和0.2。该重构表明，除了隔离之外，在封闭环境中稀释空气传播病毒浓度也很有用，高风险易感人群在暴露时应采取严格的预防措施。本研究可为其他游轮及封闭环境的防控措施提供有益启示。
