What is the probability of secondary infection after rehabilitation? Is it "good morning sun"? Can the latest mutation of the virus be detected in time In response to the current public concerns about many epidemic hot issues, the reporter from "Xinhua Viewpoint" interviewed experts from the State Council's joint prevention and control mechanism to answer them. Hotspot 1: Does the virus exist in multiple "versions" and is strong in the north and weak in the south? Recently, there has been a statement on the Internet that the infection symptoms in the north are more obvious than those in the south due to the different Omicron variants prevalent in the north and south. Xu Wenbo, director of the Institute of Viral Disease Control and Prevention of the Chinese Center for Disease Control and Prevention, introduced that the current prevalence of COVID-19 in China is dominated by BA. 5.2 and BF. 7, the subfamilies of Omikron variant BA. 5, among which, the variant prevalent in Beijing is dominated by BF. 7, and the variant prevalent in Guangzhou is dominated by BA. 5.2. From the perspective of clinical medicine, do two slightly different strains have strong or weak symptoms? Tong Zhaohui, vice president of Beijing Chaoyang Hospital affiliated to Capital Medical University and director of Beijing Institute of Respiratory Diseases, said that as long as the virus is still a branch of Omicron, its toxicity, pathogenicity and infectivity will not change substantially. As for the obvious fever and cough of some people, it is mainly different from person to person, which is related to their own immunity, age and basic diseases. Hotspot 2: Is the probability of secondary infection high after rehabilitation? Some people are very concerned about whether they will be infected again after they are infected with Omikjon and recovered? Wang Guiqiang, director of the Infectious Diseases Department of Peking University First Hospital, said that secondary infection refers to the re infection of COVID-19 after a period of time after recovery from infection, often due to the mutation of COVID-19. From the time of occurrence of secondary infection, there is usually an interval. It will not be said that secondary infection will occur soon after infection. The probability of secondary infection of the same strain is extremely low. Wang Guiqiang said that secondary infection mainly refers to breakthrough infection of mutant strains, and the time interval of breakthrough infection is closely related to clinical manifestations; The shorter the interval, the lighter the symptoms. After a long interval, the symptoms become more severe, which is directly related to the immune antibodies in the human body. Hotspot 3: Why do the convalescents have "rejuvenation"? Unlike secondary infection, "re positive" refers to the positive results of the infected person twice in the same infection cycle. Wang Guiqiang said that, to be exact, "Fuyang" should be called "re detection", which is not uncommon in previous studies. In fact, the viral nucleic acid continues to exist only because the detection and sampling methods are not standardized and the intermittence of detoxification leads to the situation of positive and negative. The nucleic acid test should be taken as the standard to determine whether the "positive" is recovered. Wang Guiqiang introduced that, from the perspective of infectivity, in previous studies, no virus was isolated from the body of "re positive" infected persons, nor did it lead to further transmission. Therefore, the infectivity after "re positive" is extremely low. From the perspective of harmfulness, only a few people have residual symptoms such as cough and discomfort, and the people who "recover" have no symptoms. Hotspot 4: Is it "good morning sun"? Wang Guiqiang said that the pathogenicity of Omikjon has decreased significantly, but some people still have clinical symptoms after infection, including fever, muscle and joint pain, throat swelling and pain, etc