应学院邀请，兰州大学王宾国教授将在线作学术报告。
报告题目：A mathematical model reveals the influence of NPIs and vaccination on SARS-CoV-2 Omicron Variant
报告摘要：In this talk, an SVEIR SARS-CoV-2 Omicron variant model is proposed to provide some insights to coordinate non-pharmaceutical interventions(NPIs) and vaccination. Mathematically, we define the basic reproduction number $R_0$ and the effective reproduction number $R_e$ to measure the infection potential of Omicron variant and formulate an optimal disease control strategy.Our inversion results imply that the sick period of Omicron variant in United States is longer than that of Delta variant in India. The decrease of the infectious periodof the infection with infectiousness implies that the risk of hospitalization is reduced; but the increasing periodof the infection with non-infectiousness signifies that Omicron variant lengthens the period of nucleic acid test being negative. Optimistically, Omicron's death rate is only a quarter of Delta's. Moreover, we forecast that the cumulative cases will exceed 100 million in United States on 28 February, 2022 and the daily confirmed cases will reach a peak on 2 February, 2022. The results of parameters sensitivity analysis imply that NPIs are helpful to reduce the number of confirmed cases. Especially, NPIs are indispensable even if all the people were vaccinated when the efficiency of vaccine is relatively low. By simulating the relationships of the effective reproduction number $R_e$, the vaccination rate and the efficacy of vaccine, we find that it is impossible to achieve the herd immunity without NPIs while the efficiency of vaccine is lower than 88.7%. Therefore, the herd immunity area is defined by the evolution of relationships between the vaccination rate and the efficacy of vaccine. Finally, we present that the disease-induced mortality rate demonstrates the periodic oscillation and an almost periodic function is deduced to match the curve.
报告时间：2022年11月17日15:00
邀 请 人：强立忠博士
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报告人简介
王宾国，理学博士，兰州大学数学与统计学院教授，硕士导师。美国“数学评论”评论员。主要从事非自治情形下传染病模型动力学行为研究。相关结果发表在J. Dyn. Diff. Equ.，J. Diff. Equ.，J. Math.Biol., European Journal of Applied Mathematics，Zeitschrift fuer Angewandte Mathematik und Physik，Discrete and Continuous Dynamical Systems A，Discrete and Continuous Dynamical Systems B,Nonlinear Dynamics上。主持天元基金、国家自然科学基金青年基金、甘肃省青年基金、国家自然科学基金卓越青年基金子课题各一项。参与国家自然科学基金重点项目一项。
