China News Service, Guangzhou, July 31 (Reporter Cheng Jingwei) Zhong Nanshan, an academician of the Chinese Academy of Engineering, said at the Air Purification World Opening Ceremony and Global Strategic Partnership Cooperation Summit held in Guangzhou on the 31st that he is very concerned about the epidemic situation of the "Charming Xiangxi" performance in Zhangjiajie, Hunan. I'm not worried about the epidemic. I have done a good job of controlling it. This is a big city. But will it be contagious in a small place (referring to Zhangjiajie)? It is still unknown."

　　Zhong Nanshan said that during the "Charming Xiangxi" performance in Zhangjiajie, more than 2,000 people gathered in the theater to watch the performance. Among them, 4 audience members were diagnosed with the new crown virus.

In such a closed environment, all viewers must now be tracked and inspected. Not only the viewers, but also their close contacts and their family members must be tracked. This has caused a huge expenditure of resources. The problem is not yet complete. solve.

　　“In places with a lot of people and poor ventilation, you must wear a good mask.” Zhong Nanshan suggested to strengthen the ventilation of indoor public buildings and buildings, and equip high-efficiency air purifiers in crowded places; avoid crowds during periods of high epidemics. For long-term stays in more places, wear a mask; avoid public transportation with poor ventilation and avoid entering small public spaces.

　　Regarding the Nanjing epidemic, Zhong Nanshan pointed out that there were concentrated outbreaks in communities near Nanjing Lukou International Airport, and the occupation of the infected population was relatively concentrated.

The Nanjing Municipal Government took timely preventive and control measures, such as closed control of Lukou Street and national nucleic acid testing, and the overall epidemic was controllable.

The delta strain at Nanjing Lukou Airport is similar in capacity, infectivity, and concealment to the virus strain that caused the Guangzhou "5.21" epidemic, and most of them are mildly ill.

　　He said that Delta virus has become the main variant of the world's new crown transmission, and the concept of "close contacts" should be updated.

In the past, the concept of "close contact" refers to family members or people in the same office who ate and held meetings within 1 meter of the confirmed case two days before the onset of the disease, but this is no longer applicable.

With regard to the concept of "close" of Delta virus, people who are in the same space, unit, building, and four days before the onset of the confirmed case are considered close contacts.

　　"One corner is uneasy, and the world is at stake."

Zhong Nanshan believes that mass vaccination to achieve herd immunity requires two to three years of global collaboration.

He emphasized that natural immunity is unrealistic, unscientific, and inhumane.

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