关键词: 新冠疫情, 工作人群, 传播速度, 疫情防控, 传染速率

Abstract: This essay mainly analyzes the trend of the epidemic, considering the influence of different populations and different protective measures on the trend of the epidemic. Firstly, the impact of different groups on the transmission of the epidemic is considered, and the transmission of the epidemic after the infection of staff and ordinary people in public places is simulated. Combined with some specific values of COVID-19, the transmission probability of the infectious disease, the number of contacts of the infectious person, the possibility of converting the latent person into the infectious person, and the total number of people in the system are determined. At the same time, the infection mechanism of the latent person and the mechanism that the cured person can be reinfected are added. On this basis, the infection rate coefficient is determined respectively according to the proportion of the number of contacts. Based on this, an improved SEIR infectious disease model is established, and the change in the number of patients is determined through simulation. Secondly, the impact of physical and chemical protection on the transmission rate of the epidemic is analyzed by comparing the transmission of the epidemic under different protective measures. Physical protection measures have good or bad effects due to different standards, materials and other protective effects. The grades of physical protection measures are divided into four levels for discussion, and the anti-epidemic effect of measures is quantified as 80%, 60%, 40%, 20%, and the control group is set up 0%. The simulation solution of the infection process is carried out respectively. In terms of chemical protection, the concept of antibody phase TS is introduced. During the antibody phase, people will not be infected by contact, and specific measures of chemical protection are taking drugs or health products, etc. After chemical protection, the antibody phase can be extended. This model is an improvement and optimization of the classic SEIR infectious disease model, and it adds the mechanism of relapse for recovered people and the mechanism of infection for latent people. Based on the difference between physical protection and chemical protection, we add a weight coefficient on the basis of the original SEIRS model, which plays a greater role in reflecting the epidemic prevention and control effect of different protective measures.
   The results show that the speed of epidemic development is reduced to different degrees after the staff takes physical protection and chemical protection measures respectively. The prevention and control effect of chemical protection measures is equivalent to the prevention and control effect of tertiary physical protection measures. Workers in public places across the country need a better physical protection than the general population in epidemic prevention and control work. The optimized infectious disease model is more in line with the actual situation of epidemic transmission and can better predict the number of possible infections in the system in the next stage. The antibody mechanism in the SEIRS model more truly reflects the impact of protective measures on the spread of the epidemic during the epidemic period, and the added incubation mechanism is more realistic than the SEIR model. In today’s era of universal vaccination, it is still necessary to pay attention to the infectiability of the novel coronavirus and combine physical protective measures,so as to prevent the spread of the epidemic.

Key words: COVID-19, working population, infection rate, epidemic prevention and control, transmission rate