报告题目：Estimating asymptomatic, undetected and total cases for the COVID-19 outbreak in Wuhan: a mathematical modeling study
报告人：阮士贵教授（美国迈阿密大学） 霍希助理教授（美国迈阿密大学） 陈静助理教授（美国诺瓦东南大学）
报告摘要：The COVID-19 outbreak in Wuhan started in December 2019 and was under control by the end of March 2020 with a total of 50,006 confirmed cases (data were obtained from the websites of Wuhan Municipal Health Commission and Health Commission of Hubei Province). Early modeling studies have greatly helped policy makers in understanding the epidemiological characteristics of COVID-19, analyzing the effect of travel restrictions on the spread, predicting possible outcomes of the outbreak, and evaluating efficacy of various nonpharmaceutical interventions (NPIs). However, the dataset of 50,006 cases (including both clinically diagnosed and laboratory confirmed) has not been studied in the literature, neither by statistical analysis nor by mathematical modeling. Moreover, the estimate of asymptomatic cases, the impact of these asymptomatic cases on the transmission dynamics, and the possibility of undetected cases have not been considered thoroughly in the literature.
In a recent paper (BMC Infect. Dis. 2021) we developed a time-dependent compartmental model to describe the dynamics of disease transmission and case detection and reporting. The model coefficients were parameterized by using the reported data and following key events and escalated control strategies. Then we used the model to calibrate the complete outbreak data, estimate asymptomatic and undetected cases, and approximate the overall antibody prevalence level. We calculated the actual attack ratios under all possible levels of fractions and infectiousness of the asymptomatic cases. Based on the reported estimates that around 20% of infections were asymptomatic and their transmission ability was about 70% of symptomatic ones, we estimated that there were about 14,448 undetected and asymptomatic cases (95% CI [12,364; 23,254]), yielding a total of 64,454 cases (95% CI [62,370; 73,260]), and the overall antibody prevalence level in the population of Wuhan was 0.745% (95% CI [0.693%, 0.814%]). We also provided estimates of the overall antibody prevalence level for different asymptomatic: symptomatic ratios and transmissibilities of asymptomatic cases. Our results indicate that the population in Wuhan is far away from establishing herd immunity and provide insights for other affected countries and regions in designing control strategies and planning vaccination programs.
阮士贵，本科和硕士毕业于华中师范大学数学系，1992年获得加拿大阿尔伯特大学(University of Alberta)数学系博士学位，1992-1994年在加拿大菲尔兹数学所(Fields Institute)和麦克马斯特大学(McMaster University)做博士后，现为美国迈阿密大学(University of Miami)数学系终身教授。主要研究领域是动力系统和微分方程及其在生物和医学中的应用。
霍希，本科毕业于中国科技大学，2014年获美国范德堡大学(Vanderbilt University)数学学博士学位，2014-2017年在加拿大瑞尔森大学(Ryerson University)和约克大学(York University)做博士后, 现为美国迈阿密大学(University of Miami)数学系助理教授。研究方向为耐药性细菌感染和传染病数学建模、带年龄结构模型等。
陈静，本科毕业于南开大学，2015年获美国迈阿密大学(University of Miami)数学系博士学位，2014-2017年在迈阿密大学做博士后,现为美国诺瓦东南大学（Nova Southeastern University）数学系助理教授。研究方向为传染病数学建模和生物统计。