This afternoon, the State Council joint prevention and control mechanism held a press conference to introduce the prevention and control of the new crown pneumonia outbreak and medical international cooperation work. Why is there a centralized isolation of incoming people rather than home observation? Wu Zunyou, chief epidemiologist at the CDC, said that some of the arrivals are asymptomatic now, but may develop symptoms during the observation period, and by the time symptoms appear, they have actually caused transmission. If the inbound person is home for observation and isolation, he or she will have living contact with family members. The infected person has already begun to detoxify during the incubation period and is already contagious in the later stages of incubation. When symptoms appear, even if measures are taken quickly to send to the hospital for diagnosis and treatment, they may have caused transmission. This phenomenon can be circumvented if you are in a centralized isolation site. Are asymptomatic infected people highly contagious? Wu Zunyou said that a recent study by the Ningbo CDC found that at the individual level, the transmission efficiency of asymptomatic infected persons is about one-third of that of confirmed cases; at the group level, the number of cases transmitted by asymptomatic infected persons accounts for only 4.4% of the total number of cases. Investigations were also done in other provinces. In one southern province, more than 1,500 close contacts of asymptomatic infected persons were observed and 7 persons were found to be ill. However, further investigation and analysis revealed that these seven people were not only exposed to asymptomatic infected persons, but also to confirmed patients, which could not be identified as being caused by asymptomatic infected persons. This co-exposure, if not carefully investigated, could potentially expand the judgment of the transmission capacity of asymptomatic infected individuals. How do asymptomatic infections arise? Zunyou Wu points out that two-thirds of asymptomatic infected persons develop into patients who are, in fact, latent. All asymptomatic infections must have a history of contact with a confirmed patient or have been to an endemic area where an outbreak is occurring and there are no newly diagnosed patients for more than two weeks, and asymptomatic infections do not suddenly appear for no reason. Wu Zunyou said that China’s current measures can detect and control asymptomatic infections in a timely manner, so the infectivity caused by asymptomatic infections is very low and will not cause proliferation at the social level. Content source: Surfing News