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BackgroundThe recent COVID-19 epidemic in mainland China is an important issue for studying the prevention and disease control measures and the spread of the COVID-19 epidemic. Following our previous study for the mainland China epidemic during December 31 2021 to 30 April 2022, this paper studies and compares the the mainland China epidemic during December 31 2021 to December 6, 2022.MethodsUsing differential equations and real word data (both domestic and foreign input infected individuals) modelings and simulates COVID-19 epidemic in mainland China during May 1 2022 to December 6 2022, estimates the transmission rates, the recovery rates, the blocking rates to the symptomatic and the asymptomatic infections, and the died rate of the symptomatic infected individuals. The transmission rates and the recovery rates of the foreign input COVID-19 infected individuals in mainland China have also been studied. Using virtual simulations predict the outcomes of the epidemics.ResultsThe simulation results were in good agreement with the real word data.The average input transmission rate of the foreign input symptomatic infection individuals was much lower than the average transmission rates of the symptomatic infection causing by the mainland symptomatic and asymptomatic individuals.The average input transmission rate of the foreign input asymptomatic infection individuals was was much lower than the average transmission rate of the asymptomatic infection causing by the mainland symptomatic individuals.The average recovery rates of the foreign input COVID-19 symptomatic and asymptomatic infected individuals were much higher than the average recovery rates of the mainland symptomatic and asymptomatic infected individuals.For the mainland epidemic simulations:If kept the transmission rates, the recovery rates, the death rate and the blocking rates on day 181 (June 30, 2022), the numbers of the current symptomatic and asymptomatic individuals would reduce to about one on day 270 (September 27, 2022).If kept the transmission rates, the recovery rates, the death rate and the blocking rates on day 340 (December 6, 2022) until day 380 (January 15, 2023), the numbers of the current symptomatic and the asymptomatic infected individuals would increase to 37 999 and 224 945, respectively, the cumulative death individuals would increase from 599 to 616.If kept the transmission rates, the recovery rates on day 340, but decreased the blocking rates to 34% and select the death rate to equal to the average death rate during days 104-150, then the simulation showed that on day 380, the numbers of current symptomatic and the asymptomatic infected individuals would increase to about 323 559 095 and 481 270 717, respectively, and the cumulative death individuals would reach about 1 055 607.For the foreign input epidemic simulations:If kept the transmission rates, the recovery rates, and the blocking rates day 242 (August 30, 2022), until day 340, the numbers of the current symptomatic and the asymptomatic infected individuals would decrease to 13 and 430, respectively.If kept the transmission rates, the recovery rates, and the blocking rates on day 340 until day 380 (January 15, 2023), the numbers of the current symptomatic and the asymptomatic infected individuals would decrease and increase to 168 and 1952, respectively.Recommendations on COVID-19 epidemic base on WHO’s technic guidelines and HBV infection experiment in Chimpanzees are provided.ConclusionsFor the mainland individuals’ epidemic, keeping the blocking rates of over 86% and 93% to the symptomatic and asymptomatic infections, and the recovery rates of over 0.119 and 0.112 to the symptomatic and asymptomatic individuals may make the numbers of the current symptomatic and asymptomatic infected individuals to decrease to very low levels in three months.For the foreign input individuals’ epidemic, keeping the transmission rates of under 0.07 to the symptomatic and asymptomatic infections, and the recovery rates of over 0.125 and 0.099 to the symptomatic and asymptomatic individuals may make the numbers of the current symptomatic and asymptomatic infected individuals to decrease to very low levels in four months.After December 6 2022, decreasing the blocking rates of under 34% to the symptomatic and asymptomatic infections may cause over 1100 millions individuals’ COVID-19 infections and over one million COVID-19 infected individuals’ death.It is necessary that administrations implement strict prevent and control strategies to prevent the spread of new COVID-19 variants.

BackgroundAfter 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.MethodsUsing 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).ResultsThe 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 RMCEThe 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.ConclusionsThe 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.