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To date, more than 71 millions on infected with COVID-19 have been identified worldwide. It causes more 1.6 millions deaths and affects more than 200 countries and regions. Establishing a mathematical model for epidemic infectious diseases has played an important role in the formulation, evaluation, and prevention of control strategies. The event of Xinfadi COVID-19 epidemic provides a successful example for prevent and control strategies and clinical treatments. This paper introduces a symptomatic-asymptomatic-recoverer differential equation model (SARDE). It gives the conditions of the stability on the disease-free equilibrium of SARDE. It proposes the necessary conditions of disease spreading. It determines the parameters of SARDE based on the reported data of Xinfadi COVID-19 epidemic and simulations. Numerical simulations of SARDE describe well the outcomes of current symptomatic individuals, current asymptomatic but infected individuals, recovered symptomatic infected individuals, and recovered asymptomatic but infected individuals. The numerical simulations suggest that both symptomatic and asymptomatic individuals cause lesser asymptomatic spread than symptomatic spread; blocking rate of 97% cannot prevent the spread of Xinfadi COVID19 epidemic; the strict prevention and control strategies implemented by Beijing government are not only very effective but also completely necessary. It is expected that the research results can provide new theoretical tools and ideas worthy of reference for better understanding and dominating of epidemic spreads, preventions and controls.
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Keywords:Epidemic and health statistics; new coronavirus; disease transmission; mathematical model; numerical simulations; Xinfadi in Beijing. |
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