Summaries, Analysis and Simulations of Recent COVID-19 Epidemic in Shanghai

Background

After successfully preventing the spread of five wave COVID-19 epidemics in Shanghai, Omicron and Delta variants have been causing a surge COVID-19 infection in this city recently. Summaries, analysis and simulations for this wave epidemic are important issues.

Methods

Using differential equations and real word data, this study modelings and simulates the recent COVID-19 epidemic in Shanghai, estimates transmission rates, recovery rates, and blocking rates to symptomatic and asymptomatic infections, and symptomatic (infected) individuals’ death rates. Visual simulations predict the outcomes of this wave Shanghai epidemic. It compares parallely with the recent mainland China COVID-19 epidemics (RMCE).

Results

The simulation results were in good agreement with the real word data at the end points of 11 investigated time-intervals. Visual simulation results showed that on the day 90, the number of the current symptomatic (infected) individuals may be between 852 and 7314, the number of the current asymptomatic (infected) individuals charged in the observations may be between 10066 and 50292, the number of the current cumulative recovered symptomatic infected individuals may be between 52070 and 74687, the number of the current cumulative asymptomatic individuals discharged from the medical observations may be between 63509 and 5164535. The number of the died symptomatic individuals may be between 801 and 1226.

• The transmission rate of the symptomatic infections caused by the symptomatic individuals was much lower than the corresponding average transmission rate of the RMCE.

• The transmission rate of the asymptomatic infections caused by the symptomatic individuals was much higher than the first 90 day’s average transmission rate of RMCE.

• The transmission rate of the symptomatic infections caused by the asymptomatic individuals was much lower than the first 60 day’s average transmission rate of RMCE, and was much higher than the last 60 day’s average transmission rate of RMCE.

• The transmission rate to the asymptomatic infections caused by the asymptomatic individuals was much higher than the corresponding average transmission rate of RMCE.

• The last 30 days’ average blocking rate to the symptomatic infections were lower than the last 30 days’ average blocking rates of RMCE

• The last 30 days’ average blocking rate to the asymptomatic infections were much higher than the last 30 days’ average blocking rate of RMCE. However the first 30 days’ average blocking rate to the asymptomatic infections were much lower than the first 30 days’ average blocking rate of RMCE.

• The first 37 days’ recovery rates of the symptomatic individuals were much lower than the corresponding first 70 days’ recovery rates of the symptomatic individuals of RMCE. The recovery rates between 38- and 52-days of the symptomatic individuals were much lower than the corresponding the recovery rates between 91- and 115-days of the symptomatic individuals of RMCE. The last week’s recovery rate was similar to the last week’s recovery rate of RMCE.

• The first 30 days’ average recovery rate recovery rate to the symptomatic individuals were much lower than the first 30 days’ average recovery rate recovery rate of RMCE. The last 30 days’ average recovery rate recovery rate of the symptomatic individuals were still much lower than the last 30 days’ average recovery rate of RMCE.

Conclusions

The last 30 days’ low blocking rates to the symptomatic infections, the first 30 day’s low blocking rates to the symptomatic infections to asymptomatic infections, the low recovery rates of the symptomatic and asymptomatic individuals, and the high transmission rate of the asymptomatic infections may be the reasons to cause the rapid spread of the recent Shanghai epidemic. It needs to implement more strict prevention and control strategies, rise the recovery rates of symptomatic and asymptomatic infections, and reduce the death rates for preventing the spread of this wave COVID-19 epidemic in Shanghai.