On the afternoon of December 15, Zhong Nanshan, an academician of the CAE Member, appeared in the national anti epidemic lecture hall of colleges and universities and gave a live lecture on the theme of "COVID-19 dynamics and response". He failed to appear at the lecture site of Sun Yat sen University because he accidentally fell down a few days ago. However, Zhong Nanshan still took more than two hours to carefully and professionally interpret the current Omicron virus and epidemic prevention policy to teachers and students across the country in the form of video. Zhong Nanshan stressed that infection with the Omicron strain was not terrible, and most of them could be completely recovered within 7-10 days. However, personal protection remains important. He also strongly called for accelerated vaccination, especially for xenogeneic vaccines. "COVID-19" has become COVID-19's upper respiratory tract infection. According to the data updated by the National Health Commission to December 6, before the emergence of COVID-19 Omikjon virus strain in China in the middle of December 2021, the cumulative number of confirmed cases is 99780, 4636 deaths, and the ratio of the number of deaths to the number of confirmed cases is 4.65%. After the emergence of the Omicron virus strain, the cumulative number of confirmed cases reached 250015, and the ratio between the number of deaths and the number of confirmed cases was 0.240%. According to the laboratory research of many units and scholars, the infection of Omicron virus strain on upper airway epithelium was significantly enhanced, while the symptoms of lower respiratory tract were significantly weakened; From the situation in China, the proportion of asymptomatic infections has also increased significantly. From the data of Guangzhou, Beijing, Chongqing and Zhengzhou since September 2022, the case fatality rate is between 0.013 and 0.019. According to the AI model trained by the Guangzhou laboratory with 5.9 million COVID-19 sequences, the analysis of the genome data of nearly 4 million people infected in the UK since the COVID-19 outbreak found that the immune escape ability of the new virus against the human immune system continued to improve, but the infection fatality rate continued to decline, especially in China and Vietnam, the case fatality rate remained at about 0.1%. "On the whole, the infection of Omicron is not terrible. Now, it has become a COVID-19 upper respiratory infection, rather than 'COVID-19'." Zhong Nanshan said. Therefore, according to the development trend of the epidemic, China has timely optimized and adjusted its epidemic prevention and control policies. At present, the focus of prevention and control policy has shifted from infection prevention and control to severe disease prevention and control. There is no virus in China that is "strong in the north and weak in the south". Recently, many people shared their experiences after being infected with Omikjon on the Internet. Others said that there are two different types of COVID-19 circulating in Beijing and Guangzhou. The toxicity of Beijing is stronger than that of Guangzhou. Zhong Nanshan introduced that the virus strain prevalent in Guangzhou, Chongqing and other places is BA. 5.2, and the virus strain prevalent in Beijing, Baoding and other places is BF. 7, but it is actually the abbreviation of BA. 5.2.1.7, a mutant based on BA. 5.2. In general, there was no significant difference between the two strains. Some people have dry throat, sore throat, dry cough, headache, fever and other symptoms, which may be very uncomfortable, but they are still mild patients. "It seems that the fever in Beijing is relatively high, which may be related to the immune escape of the virus or the temperature." Zhong Nanshan said. As for the statement that "the virus in Haidian District is weaker than that in Chaoyang District", Zhong Nanshan also said that