Mechanistic modeling of the coronavirus disease 2019 outbreak in the early phase in Wuhan

Abstract

The coronavirus disease 2019 (COVID-19) outbreak started in Wuhan, Hubei province, China in the end of 2019 and swiftly spread to the whole country and overseas, and became the first pandemic caused by a coronavirus in human history. By March, 2020, the outbreak in China has largely been under control with tremendous efforts and losses, while other regions, e.g., Europe and Middle East, are in extreme difficulty. The lesson learnt in Wuhan, Hubei shall be very valuable for battles in other regions. In this paper we propose a compartmental model to study the transmission dynamics of COVID-19. Our model incorporates different isolation strategies for mild and severe cases and is fitted to the cumulative number of confirmed cases in Wuhan from January 1 to 31, 2020, for COVID-19 epidemic to estimate some parameters. We find that the COVID-19 could have increased exponentially if strict measures were not properly implemented. We estimate the basic reproduction number to be 2.80, which could vary from 0.97 to 3.24 depending on human host susceptibility and transmissibility. Numerical simulations indicate that reducing transmission rate is the key factor for effective use simple word control of the outbreak. These results suggest that timely hospitalization/isolation of suspected and confirmed cases as well as quarantine of people who had close contact with infected cases in epidemic areas are vital to mitigate the spread of COVID-19. 2019年年底新型冠状病毒肺炎（COVID-19，简称新冠肺炎）在中国湖北省武汉市暴发并迅速蔓延至全国各地及海外，成为人类历史上首次由冠状病毒引起的全球大流行疫情.截止2020年3月18日，在做出巨大努力和付出沉重代价的前提下，中国的疫情已基本受到控制.在世界其他地区，例如欧洲和中东正处于极端困难中.湖北武汉的经验对于其他地区的抗疫工作有非常重要的参考价值.本文通过建立仓室模型来研究新冠肺炎的传播动力学，尤其探讨针对轻度和重度病例的不同隔离措施对疫情发展的影响，并且通过拟合2020年1月份武汉的累积确诊病例数来估计部分参数.结果表明，如果严格的措施不到位，新冠肺炎感染人数在短期内可能指数增长.基本再生数为2.80，受人口的易感性和传染性的影响其可在0.97至3.24之间变化.仿真结果表明，降低接触率是有效控制暴发的关键举措.在疫区对确诊和疑似病例进行及时隔离或住院，以及对密切接触者的隔离观察对减缓新冠肺炎的传播至关重要.