(Fighting against New Coronary Pneumonia) The emergence of a new variant of the new coronavirus in China, the local outbreak of Omicron BA.5, arouses concern
China News Agency, Beijing, July 7 (Reporter Li Chun) Entering July, the local epidemic of new coronary pneumonia has re-emerged in many places in China.
With the release of viral gene sequencing results, the BA.5 branch of the Omicron variant has received a new round of attention.
The first is a new round of epidemics that began in Xi'an on July 2.
According to the press conference on the prevention and control of the new crown pneumonia epidemic in Xi'an on July 5, the results of gene sequencing showed that the new crown virus strains that caused this round of epidemics were all branches of the BA. processing.
It was revealed at the press conference that the BA.5.2 branch of the Omicron variant strain spreads faster than other circulating variant strains, such as BA.2, which led to a surge in local cases in China at the beginning of this year, and the infected cases have a lower CT value. Strong sex.
It cannot be ruled out that new transmission chains will appear in the follow-up, causing a high risk of secondary transmission in the community.
In the recent new round of clustered epidemics in Beijing, the virus gene sequencing showed the same result.
Pang Xinghuo, deputy director of the Beijing Center for Disease Control and Prevention, said on the 6th that the laboratory of the Beijing Center for Disease Control and Prevention conducted genetic sequencing on the samples of the three infected persons notified on July 5, and the results showed that the virus belonged to the Omicron variant BA. .5.2 Branches.
In fact, as early as Xi'an and Beijing, the BA.5 branch of Omicron has caused local epidemics in Macau.
On June 23, He Yicheng, the chief executive of the Macao SAR, said at a press conference on the new crown epidemic that the new coronavirus strain found in Macao is Omicron BA.5.1, and it is difficult to trace the source.
At the press conference of the Joint Prevention and Control Mechanism of the State Council on June 28, Wang Wenling, a researcher at the Institute for Viral Disease Prevention and Control of the Chinese Center for Disease Control and Prevention, also confirmed that the Macao epidemic was caused by the BA.5 variant.
She also pointed out that the transmission ability and immune escape ability of the new coronavirus Omicron variant BA.4 and BA.5 have been slightly enhanced, the difficulty of prevention and control will increase, and China's foreign defense input pressure will increase.
There is a certain scientific basis for the relevant conclusions.
According to public reports, a study recently published by the team of Academician Xie Xiaoliang of Peking University and his collaborating team in the journal Nature shows that BA.5 has a strong immune escape ability. Antibodies elicited by BA.1 infection that can escape the early Omicron variant.
In addition, a study jointly published by 27 scientific research units including the University of Tokyo in Japan and the Weizmann Institute of Science in Israel showed that, compared with Omicron BA.2, BA.4 and BA.5 have a higher effect on human alveolar cells. stronger infectivity.
Some opinions point out that, unlike earlier branches such as Omikron BA.1, which mostly caused upper respiratory tract infections, BA.5 may "regain" the ability to infect the lungs and increase the severe rate.
However, some experts have different opinions on this. They believe that the above research is only an animal experiment, which is not enough to explain the problem. Epidemiological investigation is still needed to obtain important epidemiological data from retrospective research on infected people.
It is more certain that the Omicron BA.5, which caused the local epidemic in China this time, was imported from abroad.
He Yicheng pointed out that the Omicron BA.5.1 found in Macau is not a strain that is prevalent in the Mainland, but is a strain that is prevalent in the United Kingdom and the United States.
The city of Xi'an also stated that the virus that caused the current round of epidemics in the city came from abroad, but the source was not yet clear.
As early as May of this year, China reported the first case of imported Omicron variant BA.5 infection.
According to the China CDC English Weekly, on an international flight that arrived in Shanghai on April 27 this year, a 37-year-old Chinese male passenger was diagnosed with a mild case of new coronary pneumonia.
On May 13, the patient's nasopharyngeal swab sample underwent genome sequencing, and the results showed that it was the BA.5 branch of the Omicron variant.
The gene sequence of the BA.5 branch of Omicron was first uploaded on March 15 this year, from a nasopharyngeal and oropharyngeal swab collected from a patient in South Africa on February 25.
At present, Omicron BA.4 and BA.5 have become the main epidemic strains in South Africa, Portugal, Britain, Israel and other countries.
Recently, the United States and many European countries such as France and the Netherlands have also seen an increase in BA.4 and BA.5 infections.
It is known that with the continuous evolution of Ormicron mutants, the World Health Organization in May this year listed six subclades of Ormicron mutants as "variant evolutionary branches of concern under monitoring", including BA. 4. Four subclades of BA.5 and BA.2.
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