Omikon BA.5 appeared in Beijing and Xi'an. Is it more pathogenic?how to respond?

Author:Look at the think tank Time:2022.07.08

On July 6, a citizen passed by a citizen from the bell tower. From 0:00 on the day, Xi'an has implemented 7 days of temporary management and control measures. Public entertainment and leisure venues and public cultural activities have been suspended for 1 week. Photo by Zhang Yuan, a reporter from China News Agency

On July 6th, at the press conference of the Beijing New Crown Epidemium, Pang Xinghuo, deputy director of the Municipal Disease Control Center and a member of the National New Type Coronary Virus Pneumonia Expert Group, reported that the infection of the Municipal Centers for Disease Control and Prevention to report on July 5th The specimens of 1 to 3 are generated for gene sequencing, and the results show that the virus belongs to the BA.5.2 branch of Omikon. Comprehensive epidemiological survey and gene sequencing results, this round of epidemic and previous chains are different, initially considering the local clustering epidemic caused by this epidemic.

From July 4th to 6th, Beijing cumulatively reported 12 cases of new coronary pneumonia virus infections. Involved in 4 districts, among them, 8 cases of Yanqing District, 2 cases of Shunyi District, and 1 case of Tongzhou District and Changping District.

On July 5th, Omikon BA.5 subtypes, who also knows how to avoid the human immune response, were notified for the first time to break through the domestic heavy line of defense and began to cause local dissemination in the Mainland. Xi'an became the first city attacked by BA.5 in the Mainland.

Since the discovery of cases on July 2, as of 24:00 on July 5, there were 29 cases of local infections in Xi'an's epidemic, including 11 confirmed cases and 18 asymptomatic infections. On July 5th, the Xi'an Centers for Disease Control and Prevention reported that the traceability of the virus genes showed that the popular mutated strains were Amikon BA.5.2 branches.

"Hello Ba.5", on the same day, American genetic and genetic expert Eric. Topor published such a Twitter. In the picture, the number of new -crowns in the United States, Britain, Greece, New Zealand, France and other countries has been significantly recovered recently, and Omikon's new mutant BA.5 is an important promoter behind it.

The emergence of this new strain makes it more difficult to block the spread of the virus, and the effect of the existing vaccine is also declining. The prevention and control of the new crown epidemic is facing a new test.

Xi'an will take 7 days of temporary management and control measures from July 6, including public entertainment and leisure places suspend business, restaurant suspension of food, public places implement measures such as scanning code, temperature measurement, standardizing wearing masks, and ventilation disinfection. On the evening of July 5th, "Xi'an released" stated that this was not a "sealed city", but some public places were implemented for temporary control.

Wen ｜ Peng Danni

This article is reproduced from the WeChat public account "China News Weekly" (ID: chinanewsweekly). The original first was released on July 6, 2022. The original title was "Beijing and Xi'an appeared in Omikon BA.5. Is it more pathogenic? how to respond? ", Does not mean looking at the view of the think tank.

BA.5 has gradually become the mainstream strain in the world, and the pressure of external prevention input increases

It is not surprising that BA.5 comes to China, because globally, it has gradually become mainstream strains.

On June 29, the World Health Organization (WHO) stated in the latest global new crown epidemic weekend that from June 20th to June 26th, there were 4.1 million new crown cases worldwide, and the growth rate increased by 18% compared with the previous week. , Reached the highest point since April. Among them, the new Asian variant BA.4 and BA.5 of Omikon variants, or the main reasons for the epidemic.

The Omikon BA.5 sequence was first uploaded to the global influenza sharing database on March 15 this year. The sequence comes from the nasopharyngeal swabs of a patient collected in South Africa on February 25. BA.4 and BA.5 became the main new crown virus variant in South Africa in May.

BA.5 is not far from us. At the press conference of the State Council's joint prevention and control mechanism held on June 28, Wang Wenling, a researcher at the Virus Disease Institute of the China Disease Control and Control Center, introduced that since February this year, the major virus strains in China are Omikon BA.2 Asian branches series. In May, BA.4 and BA.5 were detected for the first time from the input case. Recently, the number of BA.4 and BA.5 infected from overseas input cases has gradually increased significantly.

At the end of May, the China Disease Control and Prevention Center released an English report that China has found the first infection of the first new crown virus Omiko Virus, which was entered overseas. The weekly report showed that the case departed from Uganda on April 25, and was transferred to Shanghai by Amsterdam and Seoul, South Korea. It was discharged on May 12. The results of the genome sequencing show that the patient infected the BA.5 mutant strain.

"From the results of the preliminary preliminary research, the propagation power and immune escape ability of BA.4 and BA.5 of the new crown virus Omikon are slightly enhanced, and the difficulty of prevention and control will increase. Increased. "At the press conference, Wang Wenling said.

BA.4 and BA.5 often put them together to study and follow, because the mutation site is the same, they can see their relationship as a very close "twin". However It's faster.

In many countries, BA.4/5 has defeated its predecessors with stronger advantages. In Israel, the director of the Ministry of Health Nachman Ash said on June 19 that a new wave of infection may have come. With the proportion of Omiko's mutant BA.5 in Israel, the number of new cases in Israel exceeded 10,000 again. In late May, the new daily increase in Israel fell to 2,000 cases. As a response, in the early stages of the new wave of epidemic, the Israeli Ministry of Health did not intend to impose extensive restrictions on large rally as before, but it has been considered to re -implement the rules of wearing masks in the closed public space; And the possibility of providing fifth -needle vaccine with low immune function.

The number of new crown cases in the United States has increased again from April, and it has once again become the country with the largest new cases in the world. In the past two weeks, the number of new cases in the United States has increased by 12%, and more than 110,000 people are infected every day; the number of hospitalizations has increased by 10%.

According to the latest data from the U.S. Centers for Disease Control and Prevention, as of the week of Sunday, July 2, more than 70%of the United States had more new diagnosis of BA.4 and BA.5 infection, of which BA.5 accounted for 53.6%. A week ago, BA.4 and BA.5 infected 55.3%of the new diagnosis.

At the same time, BA2.12.1 has no longer the main popular strain in the United States since the last week. The proportion of new diagnosis has been lower than BA.5, from 39.2%a week ago The proportion of new diagnosis dropped to 2.8%, below 5.7%below a week ago.

A large -scale new crown epidemic in Macau China is caused by BA.5. Macau, which has no new local diagnosis cases for more than 200 days, has organized multiple rounds of national nucleic acid testing. The Macau Infection Response Coordination Center reported on July 5 that from June 19, Macau has reported 941 confirmed cases.

In Taiwan, China, due to the slowdown of the epidemic, the number of days of entry isolation has recently reduced from 7+7 to 3+4. The Taiwan epidemic prevention department said that one of the reasons for the abolition of inbound nucleic acid detection and isolation in the short term is the threat of BA.5. The local epidemic prevention department conducted a preface of virus genes from 182 overseas input cases from June 9th to June 26th, and found that BA.5 strains accounted for about 52%.

Ma Chaofeng, deputy director of the Xi'an Centers for Disease Control and Prevention, introduced on July 5 that the main area of this epidemic was the largest renewable resource trading market in Shaanxi Province, involving a wide range of people and complicated personnel. This professional population has a large scope and many contacts. Many of them involved multiple restaurants, supermarkets, communities, large trading markets, high -speed service areas and other people with a large place of activities before controlling control.

He said, plus BA.2, which was popular in the popular Omeck Rongfeng strain, has spread faster than the surge in domestic local cases earlier this year. Therefore, the current situation of Xi'an City is severe and complicated. The new communication chain has caused the community to renew the risk of dissemination.

At the press conference in Beijing on July 6, Pang Xinghuo said that as of now, except for a case of a infected person reported yesterday, the other infected people were close contact with them, all of which were isolation observer. The spread chain is clear and the source is clear. According to the existing epidemic development trend, it is initially believed that the epidemic situation is generally controllable.

Is the immune escape ability reaching a new height, will the pathogenicity be stronger?

Eric Topor described that Omircong's variant BA.5 is the worst virus version we have ever seen. It has raised immune escape to a new level, and because of this change, its spread has also been strengthened, far exceeding the other variants of the Omikon family.

BA.4/5 is the subtype of Omikon, but compared to the original Omikon, there are many differences, because it has combined some characteristics of Delta. Liu Shan, a virusist at Ohio State University, told reporters.

Liu Shanshi introduced that BA.4/5 has evolved from BA.2. Originally, BA.2 was more disseminated than the original strain of Omikon, and BA.4/5 was stronger on it. A little.

There are only 6 differences in the spiny protein of the new coronal virus in BA.4/5 and BA.2. However, the mutation of one of the sites L452R is critical, and this mutation appears in Delta strains. An analysis of a virusist at the University of Tokyo said that this mutation may make the virus easier to combine with cells and have a better replication ability.

On June 17, "Nature" published papers from the Peking University Biomedical Frontier Innovation Center, the School of Life Sciences of Peking University, and the Institute of Biology of the Chinese Academy of Sciences. Studies have found that Omik Rongya variant BA.2.12.1, BA.4, BA.5 shows stronger immune escape ability, and has a significant place for the plasma after recovery of Omikon BA.1 infected. Neutral escape phenomenon.

In Portugal, BA.5 has accounted for 80%of the viruses infected by all confirmed cases in June. Although Portugal's vaccination rate exceeds 85 %, and from the end of 2021 to the beginning of 2022, a large number of infections of Omikon BA.1 and BA.2 have just experienced a new wave of infection in Portugal. It also returned to the level at its peak from January to February 2022 to February. Regarding its pathogenicity, there are currently only sporadic laboratory studies. Researchers such as Kumamoto University, University of Tokyo University, University of Tokyo at the end of May, published on the Biorxiv website without peer evaluation and pre -printing research showed that in animal experiments, compared with BA.2, infection BA.4 and BA compared to BA.2, infection BA.4 and BA The hamster of .5 was much higher in oral samples and virus loads around the lungs. Three to five days after infection, the virus load around the lungs of the BA.4 and BA.5 hamsters is 5.7 and 4.2 times that of the BA.2 hamsters. In vitro experiments in some laboratories have found that BA.4/5 has increased in terms of communication, pathogenicity and immune escape from the initial Omikon.

Whether BA.4/5 can go to the lungs is the focus of public attention. An article published by American genetic and genetic science expert Eric Toppol on June 28 stated that many studies have found that BA.4/5 is by far the most immune escape ability to react with low levels and antibodies. variant. He believes that these two subspecies have strong ability to severely cause severe illness, because they replicate and spread in the lung cells in lung cells are much faster than other Omikon variants.

In the past, in accordance with the rules of the virus, in order to adapt to human host, the virus usually became weaker and weaker in evolution to coexist with humans. Revelation: This law is not linear. Liu Shanzhu said that viruses are sometimes enhanced during evolution, which has something to do with the pressure facing the external environment and viruses.

Of course, it is still difficult to concluded that its pathogenicity is strong. For example, in South Africa, BA.5 has not set off any storms in terms of hospitalization and mortality; In the past 6 weeks, its severe illnesses and hospitalization rates have risen. But it is difficult to attribute behind these phenomena. Invasions such as WHO, European Disease Prevention and Control Center, etc., all pointed out in the report in late June that there is no evidence that there is currently no evidence that Omikon BA.4 and BA.5 will cause more serious diseases than previous variants.

A report from the French Ministry of Health on June 15 pointed out that compared with BA.1 infected people, some common clinical symptoms of BA.4/5 infected people such as fatigue, cough, fever, headache, etc. The duration has increased from 4 days infected by BA.1 for 7 days. Compared with BA.1, the hospitalization rate of BA.4/BA.5 has not increased significantly.

The agency also pointed out that the median age of this wave of BA.4/5 infection is greater and the proportion of risk factors is higher. Not only is the endotoxicity of the virus itself, the age of infected people, the history of previous infections, and vaccination can all affect the actual clinical symptoms. The Ministry of Health of France emphasized that high -risk population should be protected, vaccination is strengthened, and mutant monitoring is continuously performed.

Liu Shanshi believes that the pathogenicity of the mutant plant in the real world must wait for the further result, because the large -scale data of the crowd always lag behind viral research for several weeks, even a month or two, but for a month or two, but Still be vigilant.

Public health measures are still effective, and new crown vaccines with stronger specificity are required

Because of its strong immune escape ability, in terms of vaccine protection, laboratory studies unanimously stated that the effects of antibodies caused by vaccination in vaccination in blocking BA.4 and BA.5 are not as good as early Omiko strains. Even people with mixed immunity, that is, those who have vaccinated vaccination and have infected with Omikon BA.1, the antibodies produced are difficult to neutralize BA.4 and BA.5.

On June 22, the New England Medical Magazine published the latest research from the Beth Israel Deacones Medical Center of Harvard University. The study found that after 2 weeks after the inoculation of the MRNA vaccine was vaccinated, the subject's neutralized antibody titer dropped 21 times the original venom of the new coronal virus to BA.4/5. Similarly, this study also shows that BA.2.12.1, BA.4 and BA.5 can also escape the immunity brought by BA.1 and BA.2.

On June 20, a Chinese study published in "Liuye Knife · Infectious Diseases" showed that after vaccination of two doses of national medicine, it was targeted at Omikon BA.2.12.1 and ba.4 and ba. 5 The neutral antibodies of the 5 -type subtype can not be detected to a large extent. After inoculation, the neutral antibody can only be detected.

At present, Modera and Pfizer are also developing binary vaccines based on the original strains and Omikon BA.1. Pfizer's press release on June 25 pointed out that in the neutralized and test of the serum of the serum of the 56 -year -old and over the test, the serum of the athletes of the Pfizer binary new crown vaccine can be effectively neutralized and BA.4 /Ba.5, but titer is about 3 times lower than BA.1. However, in view of the strong popularity and virus characteristics of BA.4/5, since the end of June, the US FDA has continued to meet, requiring the research and development of the new crown vaccine of vaccine research and development companies to make adjustments, and the specificity of the vaccine should be considered for BA.4/5.

不过，刘善虑也指出，BA.4/5实质上并不是巨大的变化，只是在奥密克戎原始株的基础上，诸如免疫逃避能力等一些功能增强了，但是有可能慢慢地， The characteristics of the mutant plant will weaken. He pointed out that vaccination is still the key. Scientists agree that the vaccine and strengthening needle have not been fully invalidated. The current immunity activated by the vaccine can still provide effective protection for intensiveness, hospitalization and death at the face of BA.4/5. Starting from July 11, people entering the gathering venue must vaccinate.

Jin Dongyan, a professor at the School of Biomedicine of the University of Hong Kong and an expert in virus, told reporters that it is basic to vaccinates the domestic vaccine for three stitches in China. If the second -generation vaccine will be strengthened as the fourth pins of Omikon, the effect will naturally be better than the existing vaccine.

On May 31, the University of Hong Kong Medical College and Sinopharm Group announced the cooperation to launch the vaccine clinical trial of the second -generation Omiko strain. Adult volunteers with two or three doses or MRNA new crown vaccines. According to Jin Dongyan's understanding, the above clinical trials should be disclosed in more complete data after 2-3 months. At that time, it is just autumn and winter. This vaccine is expected to come in handy.

BA.4/5 is likely to become the next domestic popular strain. Wei Sheng, a professor at the Public Health College of Tongji Medical College of Huazhong University of Science and Technology, told reporters that the current dynamic clearance measures in China are still effective for new mutations, because it is because it It does not rely on vaccines and drugs, so the current biological changes of Omiko strains should not have much impact.

He believes that normalized nucleic acid testing, combined with rapid current and public health control measures, is still the key to maintaining a large cities. Xi'an's epidemic situation and trend should also provide some experience.

Wang Wenling, a researcher at the China Centers for Disease Control and Control, said that China CDC will closely pay attention to the trend of BA.4 and BA.5 in the country, promptly follow up the research progress of new mutant plants around the world, evaluate and judge in a timely manner, and guide all localities to implement the first place. The requirements of the ninth edition of the prevention and control plan, scientifically and precisely do the prevention and control of the Omikon mutant epidemic.

The new coronal virus has not stopped its evolution, and BA.5 is not the last mutant. Virus monitoring, vaccine renewal, and adjustment of public health measures will be long -term efforts.

As of July 2, researchers in various countries have discovered 85 BA.2.75 gene sequences in the international new coronary virus genome databases such as "GISAID". This variant first appeared in the gene sequence from India in early June, and then quickly appeared in 7 other countries including the United Kingdom, the United States, Japan, Canada, Australia, New Zealand, Germany, etc. Some experts said, "This new strain may be more or more. Infectious. "

Uncle Ku Welfare