Our reporter Ye Qing

  "If effective and timely measures are not taken, according to model predictions, this round of the epidemic in Guangzhou will probably infect 7.3 million people." On June 25, Zhong Nanshan, an academician of the Chinese Academy of Engineering, was interviewed by the media.

He believes that the Guangzhou epidemic can be said to have been effectively controlled. “My personal judgment is that in the first phase of my country’s battle against the spread of delta mutant strains in the community, Guangzhou has achieved initial results. These experiences will help the country’s epidemic prevention and control. All help."

  How is the situation in Guangdong?

Are domestic vaccines effective against delta variants?

Can animals cause the virus to spread?

He responded one by one.

  The viral load of the mutant strain is 100 times higher than that of the ordinary strain

  With the outbreak of the new crown epidemic in India, the delta variant quickly became the focus of the world.

It is coming fiercely, becoming the most important virus strain for new cases in the United Kingdom, Russia, Singapore, the United States and other countries.

  Since May 21, two of the local epidemics that have occurred in Guangdong have also been caused by the Delta mutant strain.

One was a locally clustered epidemic that occurred in Liwan District, Guangzhou and related cities on May 21. As of June 24, a total of 167 cases of infection had been reported; the other was an epidemic caused at Shenzhen Airport on June 14. A total of 7 cases of infection have been reported.

  "Shenzhen's Delta mutant has different mutation sites and different sources from Guangzhou's Delta mutant strain." Zhong Nanshan said, "The viral load of the Delta mutant strain in humans is 100 times higher than that of ordinary strains, and its transmission power is stronger; The incubation period in the body is short, and the onset occurs within 1-3 days; the time to turn negative in the body is also long. The average time to turn negative in Guangzhou cases is 13-15 days, and a few can reach more than 20 days, which is much longer than that of ordinary plants. -9 days."

  Because of the high viral load in the infected person's body, the infectivity has increased.

"In the early stage of the epidemic, 5 generations of transmission within 10 days, the transmission index is as high as 4.04-5.0. If effective and timely measures are not taken, according to model predictions, this round of the epidemic in Guangzhou will probably infect 7.3 million people." Zhong Nanshan pointed out that the Guangzhou epidemic can be said to be Has been effectively controlled.

"I personally judge that Guangzhou has achieved phased results in the first phase of our country's battle against the spread of the delta mutant strain in the community."

  Rule out the spread of the virus through animal excrement

  Zhong Nanshan pointed out that during this period, in addition to adopting effective prevention and control methods for the new outbreak in Beijing, Guangzhou also adopted some innovative scientific management measures based on the infection characteristics of the delta mutant strain.

  Quickly locate the source of infection and accurately identify the chain of transmission.

After receiving the report on May 21, the source of the infection was identified at 3 pm that day.

Afterwards, through high-quality epidemiological investigations and timely gene sequencing traceability, a clear chain of transmission and epidemiological connection were found, and the chain of transmission was very clear.

  The concept of "close connection" has been updated.

"The delta mutant strain has a high viral load, a large concentration of the virus exhaled from the respiratory tract, and is extremely contagious. Therefore, the concept of close contact in the past is no longer applicable. In the past, the close contact was considered to be the family, the same office, and 1 Having eaten and held meetings within a meter, now it’s changed to the same space, the same unit, the same building and the infected person who had been together 4 days before the onset of illness. According to this classification, different control modes such as closed and closed control have been formulated." Zhong Nanshan Say.

  In addition, Guangdong established the “yellow code” system for the first time in the country, requiring the “yellow code” personnel to complete nucleic acid testing as soon as possible within 24 hours.

As of June 24, there has been no spillover from outside the province in this epidemic.

  While adopting scientific management measures, Guangdong's research on the spread of the virus is also in full swing.

"We have always suspected that animals may cause the spread of the virus, so we placed squirrel cages in closed areas where the epidemic occurred. A total of 70 rodents were trapped, and 44 valid rat throat swab specimens were collected. The results of the new coronavirus nucleic acid test were all negative, which was ruled out. The new crown virus may spread through animal excrement in closed and sealed areas." Academician Zhong Nanshan said.

  In the next step, Guangdong will carry out a seroepidemiological investigation of the new coronavirus infection in companion animals, cats and dogs.

It is planned to collect serum samples from cats and dogs to complete the flow of animal and pet infection and transmission. This work is expected to be completed by the end of July.

  Home-made vaccines have a protective effect on the population

  How should we protect against the delta mutants that may reappear?

"Because of its extremely high infection intensity, the fever clinics in hospitals should strengthen control measures." Zhong Nanshan pointed out that it is difficult for most central hospitals to achieve fever clinics with 20 meters apart, but they should also be strictly controlled, strengthened physical partitions, and site selection. Relatively independent, pay attention to the location of the wind direction, which is different from the entrance and exit of ordinary outpatients.

  “Shenzhen and Guangzhou accept nearly 80% of the country’s international immigrants, and the imported epidemics may continue to appear in the future.” He revealed that Guangzhou is planning to establish a “Guangzhou International Health Station” covering an area of ​​250,000 square meters. 5000 independent rooms, which can greatly reduce the possibility of imported infections.

  Zhong Nanshan has repeatedly emphasized the importance of vaccination.

"Now the whole world is facing the epidemic of the new crown delta strain. Epidemic prevention and control and economic recovery must establish a new balance." He believes that in addition to strict compliance with group prevention and control measures, vaccination should be promoted as soon as possible. , The establishment of herd immunity.

  He especially responded to the question of whether the domestic vaccine is useful for the delta variant.

"Laboratory results prove that vaccination with domestic vaccines has a protective effect on the population." Zhong Nanshan said that preliminary analysis shows that the prevention effect of completing the whole course of immunization is obvious. The vaccine is effective in preventing infection of close contacts by 69% and preventing the development of pneumonia. It is 73%, and the effect of preventing severe illness is over 95%.

"According to observations in Guangdong Province, close contacts who have received two doses of the vaccine have nearly 60% protection against disease and nearly 80% protection against pneumonia. No patient has become severe or critically ill."

  Zhong Nanshan emphasized that if the protection rate of the vaccine is 70%, more than 80% of the population needs to be vaccinated to establish herd immunity, and we need to speed up the vaccination.

  “The whole world is at risk if the whole world is uneasy. If the epidemic in other countries is not well controlled, the country will never be opened.” He said that he hopes to rely on the strength of the United Nations and the World Health Organization to achieve vaccine sharing. Only the joint efforts of multiple parties can restore normalcy. International exchanges.