Today (December 31), the team of Academician Chen Saijuan of Shanghai Jiaotong University School of Medicine and Fan Xiaohong's team of Shanghai Public Health Center jointly released the new research results of the two teams' joint research-evaluating the epidemic trend of new crown infection in autumn and winter of 2022.

The results of this research were recently published in the paper "Primary assessment of the diversity of Omicron sublineages and the epidemiologic features of autumn/winter 2022 COVID-19 in China" -19 wave in Chinese mainland), published in Frontiers of Medicine.

　　On December 26, 2022, the state officially promulgated the "Overall Plan for the Implementation of "Class B and B Control" for Novel Coronavirus Infection", which will be implemented from January 8, 2023.

In order to assess the transmission mode of the Omicron strain in the country after the adjustment of epidemic prevention measures, the possible proportion of severe cases among symptomatic infections, and the trend of this wave of epidemics in large cities and rural areas in the central and western regions, Chen Saijuan's team and Fan Xiaohong's team jointly tackled key problems , analyze the current prevalence of Omicron subtypes in the country, the proportion of critically ill patients among infected and hospitalized patients, and use mathematical modeling to simulate and predict the trend of the epidemic.

　　Chen Saijuan said that among the people who have recently experienced symptoms of new coronavirus infection, the severe cases are mainly concentrated in the elderly group with underlying diseases. New Year's Day and Spring Festival are coming, and rural areas with relatively weak medical resources must attract special attention.

The main epidemic strains are BF.7, BA.5.2, BQ.1, XBB, and no new mutant strains have been seen

　　The type of virus strain is one of the topics that the domestic public is most concerned about recently.

The research team performed genome sequencing on 378 randomly selected samples from patients admitted to the Shanghai Public Health Center during the autumn and winter of 2022, and obtained 369 high-quality full-genome sequences of the new coronavirus.

The picture shows the situation of patients with different strains released by the research team.

Photo courtesy of the research team

　　Through molecular phylogenetic tree analysis, the research team found that 369 high-quality viral genomes contained 30 Omicron subtype strains recorded in the Global Initiative for Sharing All Influenza Data (GISAID) database, of which 355 (95.95%) genome sequences Concentrated on five Aomikron sublineages, the main strains include BF.7 and BA.5.2 that have been reported to be prevalent in Beijing and Guangzhou, and BQ.1 and XBB that have recently appeared in Europe and the United States.

　　Combined with the travel history and infection contact history of the infected person, it is proved that those with a history of contact with the epidemic in Beijing or Guangzhou mainly carried the BF.7 and BA.5.2 substrains respectively; the infected persons entering Shanghai from overseas mainly carried BQ.1 and XBB; Among the local infected persons, in addition to BA.5.2, there are several Aomecron sub-strains with a relatively high proportion.

No new coronavirus variants have been identified in these results.

Among the 5,706 infected patients, 173 were severely ill and critically ill, and the elderly and men were at high risk

　　Since the task of fighting the new crown infection has shifted to the prevention and treatment of severe cases, the research team analyzed the changes in the number of severe/critically ill patients and the total number of infected persons in this wave of epidemics as of November 29, 2022 based on public information, and found that severe/critically ill The number of critically ill patients increased with the increase in the number of infected patients, reaching 0.035%.

　　According to the general rule, high-risk groups evolve into severe and critically ill patients 2-3 weeks after admission.

Therefore, the research team analyzed the clinical evolution of 5,706 patients with symptomatic new coronavirus infection admitted to the Shanghai Public Health Center from September 1, 2022 to December 26, 2022. After comprehensive medical observation and diagnosis, 5,533 of them The remaining 173 patients progressed to severe/critical illness (3.03% total), including 20 patients with only new crown infection (0.35%) and 153 patients with Patients with basic diseases aggravated by new crown infection (total proportion 2.68%).

　　In addition, older people (over 55-60 years old) and male patients have a significantly higher risk of developing severe/critical illness.

From New Year's Day to the Spring Festival, the new crown epidemic will mainly affect rural areas and small and medium-sized cities and towns

　　The research team also used mathematical models to preliminarily predict the direction of the Omicron epidemic.

Based on the data of infected persons from routine nucleic acid testing in Beijing, Guangzhou, Shanghai, Chongqing and other places, a mathematical model was established to simulate the curve of the number of infected persons, to evaluate and predict the recent development trend of the epidemic, and to preliminarily judge the infection of this round of Omicron epidemic The number of people will come to an end in the above-mentioned major cities around New Year's Day in 2023.

The picture shows the proportion of critically ill patients analyzed by the research team, provided by the research team

　　However, the mathematical simulation analysis based on the data of the main urban area and the suburbs of Chongqing suggests that the peak of the epidemic is delayed in the suburbs, and the peak of infection will be significantly enhanced during the Spring Festival travel period due to the accelerated spread of the epidemic.

For Sichuan, Shaanxi, Gansu, Qinghai and other provinces, the progress of the epidemic in the population excluding the provincial capitals is predicted. It is estimated that the peak of infection in rural areas and small and medium-sized cities and towns will appear in the middle and late January of 2023. Due to the Spring Festival travel, these peaks Arriving early is also possible.

　　Based on the above research results, the team analyzed that with the change of the virus transmission route brought about by the evolution of the epidemic, multiple Omecro subtypes spread simultaneously in the country; among the people who have recently experienced symptoms of new coronavirus infection, the severe cases are mainly concentrated in those with underlying diseases Among the elderly group; from New Year's Day to the Spring Festival, the new crown epidemic will mainly affect rural areas and small and medium-sized cities and towns.

　　What deserves special attention is that domestic rural areas and small and medium-sized urban areas are relatively scarce in medical resources, and there are a large number of elderly people and people with underlying diseases; the mobility of urban and rural populations during the Spring Festival travel season will greatly affect the trend of the epidemic.

　　Therefore, the team suggested that there is an urgent need to start an emergency plan for the spread of the Omicron epidemic to rural areas, allocate more medical resources to rural grassroots, do a good job in emergency use of effective drugs and new vaccines, and do a good job of anti-new coronavirus specific drugs and supplementary drugs, the production reserve, distribution and clinical rational use of traditional Chinese medicines with definite curative effects; implement classified and layered treatment, and strengthen the ability to treat severe cases in small and medium-sized towns; continue to make good use of non-drug public health measures (wearing N95 masks in indoor spaces) , maintain social distance, appropriately increase the frequency of public transportation to avoid crowding, etc.), strive to reduce the peak of the epidemic, and relieve the heavy pressure on the medical system and medical staff; continue to immunize high-risk groups throughout the process, and start the fourth round of vaccination for high-risk groups Needle immunization and booster vaccination; strengthen the popularization of personal and family prevention and control knowledge and skills, do a good job in health publicity and risk communication, protect the lives and health of the people, especially those in need, and ensure that our country can walk out of the epidemic smoothly.

　　China Youth Daily and China Youth Net reporter Wang Yejie