Research On Seir Model Of COVID-19 Virus Infection

Infectious diseases have always been one of the main killers among diseases that threaten the safety of human life.So far,there have been many outbreaks of infectious diseases in the world,such as the Black Death,SARS,H1N1 influenza and so on.Therefore,studying the transmission mechanism of infectious diseases is of great practical significance.Nowadays,establishing dynamic models of infectious disease to study the epidemic development rules of infectious diseases is a most common method,which is applied in quantitative analysis.Through establishing corresponding dynamic models according to the transmission mechanism of different infectious diseases,the established model could be more suitable for the actual situation of infectious diseases,which could also ensure the reliability of the estimated parameters.In this paper,an improved SEIR model is established based on the feature that patients infected with new coronavirus are also infectious during the incubation period.Also,the equilibrium point and the stability of the equilibrium point are analyzed.Then,the overall epidemic situation in China and the epidemic situation in Diamond Princess are analyzed empirically through the improved SEIR model.In the part of empirical analysis,the maximum likelihood estimation is used to estimate the related parameters in the model,mainly including the infection rate coefficient,control coefficient,basic regeneration number and the specific time when the effective regeneration is reduced to1.At the same time,the fitting curves that show the cumulative number of people diagnosed in the overall epidemic situation in China and the epidemic outbreak in Diamond Princess.Studies show that before the implementation of the epidemic control measures,both the basic regeneration number R₀ of the outbreak situation in China and in Diamond Princess is greater than 1,which indicates that if there is no external control,a risk of endemic diseases exists.After the implementation of the epidemic control measures,The control coefficients on different infection ways in China's overall situation and in Diamond Princess(including patients during incubation period and infected people)is greater than 0.Meanwhile,the effective regeneration number drops to 1 at the time points of February 6^th,2020 and February 18^th,2020,which manifests that the intervention measures taken by Chinese government as well as taken on the Diamond Princess are effective in preventing the further spread of the epidemic.In addition,the improved SEIR model is found to have a smaller RMSE than the traditional SIR model and SEIR model through comparison,which is more in line with the actual situation of the coronavirus pandemic.