The isolation measures will no longer be implemented for people infected with COVID-19, and close contacts will no longer be judged; No longer delimit high and low risk areas; The detection strategy is adjusted to "willing to complete inspection"; Cancellation of nucleic acid testing and centralized isolation of all staff after entry... Recently, the National Health Commission announced that novel coronavirus infection will be adjusted from "Class B A tube" to "Class B B tube" from January 8, 2023. This is another major adjustment of the COVID-19 prevention and control policy since China began to implement strict Class A prevention and control measures for infectious diseases on January 20, 2020. It is an important experience of epidemic prevention and control in China to make decisions based on time and situation and prevent and control diseases scientifically and accurately. It is also an inevitable choice to ensure people's health and safety and economic and social development. More than 1.4 billion people fought against the epidemic with one heart and perseverance, effectively responded to the impact of five waves of epidemic in the world, successfully avoided the spread of relatively virulent original strains, delta mutants and other large scale epidemics in China, greatly reduced the severity and death, and also won precious time for the development and application of vaccines, drugs, medical resources and other preparations. Through the joint efforts of all parties, the epidemic situation and the number of deaths in China have remained at the lowest level in the world, the people's health has been steadily improved, and major positive results have been achieved in coordinating epidemic prevention and control and economic and social development. Practice has fully proved that China's epidemic prevention and control policy is correct, scientific and effective, has been recognized by the people, and can stand the test of history. At present, China's epidemic prevention and control is facing new situations and tasks, and the prevention and control work has entered a new stage. Experts at home and abroad generally believe that the main direction of COVID-19 variation is lower pathogenicity, more inclined to upper respiratory tract infection and shorter incubation period. The variant strain of Omicron has become the dominant strain in the global epidemic. Although it has a large number of infections, its pathogenicity has decreased significantly in the early stage, and the disease caused by it will gradually evolve into a common respiratory infectious disease. At the same time, after nearly three years of epidemic resistance, China's health care and disease control system has withstood the test, with effective diagnosis and treatment technology and drugs, especially traditional Chinese medicine. The complete vaccination rate of the whole population has exceeded 90%, and the health awareness and literacy of the people have significantly improved, creating conditions for further optimizing and improving prevention and control measures. The adjustment of COVID-19 infection from "Class B A control" to "Class B B control" in accordance with the law is an adjustment of the prevention and control strategy based on a comprehensive assessment of the virus mutation, epidemic situation and prevention and control work in China, which reflects the fact seeking, active action, optimization and improvement of the prevention and control policy according to the situation, helps to improve the scientificity, accuracy and effectiveness of the prevention and control work, and helps to better ensure normal production, life and medical and health needs, It will help minimize the impact of the epidemic on economic and social development. The implementation of "Class B and Class B management" is not to let go, but to strengthen service and guarantee. At present, the COVID-19 epidemic continues to spread around the world, and the domestic epidemic is generally in a rapid rise stage. Due to the differences in population mobility, population density, population immunity level, etc., the epidemic is welcomed everywhere