A new situation in the domestic epidemic: the “worst” mutant virus has been introduced to many places and restarted nucleic acid testing – yqqlm

Original title: A new situation in the domestic epidemic: the “worst” mutant strain was introduced and restarted nucleic acid testing in many places

Recently, local epidemics have reappeared in many places. According to a report by the National Health Commission on the 11th involving 12 provinces and cities, from 0 to 24:00 on July 10, 31 provinces (autonomous regions and municipalities) and the Xinjiang Production and Construction Corps reported 46 local cases (17 in Guangdong, 9 in Anhui, There are 6 cases in Shanghai, 4 cases in Jiangsu, 2 cases in Hainan, 2 cases in Gansu, 1 case in Beijing, 1 case in Inner Mongolia, 1 case in Zhejiang, 1 case in Shandong, 1 case in Shaanxi, and 1 case in Qinghai).

Among them, in the new outbreaks in Xi’an, Beijing, and Shanghai, the virus gene sequencing of the infected people successively pointed to the branch of Omicron BA.5.2 with stronger transmission.

Will there be a new round of epidemics when new strains land in Beijing and Xi’an, causing a cluster of epidemics?

Just last week, after 29 new cases of positive infection in 4 days, Xi’an started the most severe epidemic prevention measures after the Spring Festival this year – the city implemented a 7-day temporary control, including the suspension of dine-in, entertainment venues, and public culture. Activity venues, kindergartens, primary and secondary schools have early holidays… The virus that caused the outbreak in Xi’an is a new variant of the new coronavirus – strain BA.5, which is also considered to be the most infectious strain at present.

In an article published on medRxiv by researchers in South Africa, where the new strain originated, the new strain’s R0 value (the most important measure of a virus’s ability to spread) — as high as 18.6 — is more than ever recorded in humans The most transmissible virus, measles.

Not only Xi’an, but the virus gene sequencing results that triggered a new round of clustered outbreaks in Beijing showed that it also came from BA.5.

It is still difficult to predict what BA.5 with stronger transmission will bring to a country like China, which has hardly experienced a large-scale epidemic.

According to a recent report by the Chinese Center for Disease Control and Prevention, China has discovered the first case of an infected person imported from abroad with the mutant strain of Omicron BA.5 (hereinafter referred to as BA.5). The infected person departed from Uganda on April 25, transited in Amsterdam, the Netherlands, and Seoul, South Korea, and arrived at Shanghai Pudong International Airport on April 27. After the diagnosis, he was transferred to the Shanghai Public Health Clinical Center for treatment, and he recovered and was discharged from the hospital on May 12.

On June 28, at the press conference of the Joint Prevention and Control Mechanism of the State Council, Wang Wenling, a researcher at the Institute of Viral Diseases of the Chinese Center for Disease Control and Prevention, said that since February this year, the main virus strain circulating in my country is the Omicron BA.2 sub-branch series. In May, BA.4 and BA.5 were detected for the first time from imported cases in China. Recently, the number of BA.4 and BA.5 infected people found in imported cases has shown a gradual increase. Recently, the epidemic in Macao in my country was caused by the BA.5 variant. At present, the epidemic strains in various parts of the country are still the BA.2 sub-branch series of Omicron. According to Wang Wenling, the latest analysis results of the Global Viral Gene Sharing Database (GISAID) show that the top three Omicron sub-clades are BA.5, BA.2 and BA.4, and the recent proportion of BA.5 has increased. Rapid upward trend. At present, BA.4 and BA.5 have become the main epidemic strains in South Africa, Portugal, the United Kingdom, Israel and other countries; recently, France, the Netherlands and other European countries and the United States have also seen an increase in BA.4 and BA.5 infections. . Some experts predict that the world may face a new wave of popularity caused by BA.4 or BA.5 this summer.

“Judging from the existing preliminary research results, 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 increase.” Wang Wenling said.

What is the mutant strain BA.5?Study says more transmission, or regains the ability to infect the lungs

Research suggests that BA.5 has the ability to escape from immunity. Even if you have been infected with Omicron BA.2 before, you may be infected with BA.5 again.

This new branch was first reported in South Africa in January this year, and then quickly became the dominant strain in the world in the past six months. Some public health experts said that the production of BA.5 was expected, but its popularity was surprising, and it has the characteristics of becoming the next global pandemic variant.

So, what are the characteristics of BA.5 compared to other mutant strains?

Rt values ​​are higher.On February 25, 2022, BA.5 was detected for the first time in South Africa, and as of May 26, 2022, 31 countries around the world had detected BA.5 infections, among the number of new cases in a single day in the world. , BA.5 accounted for about 2%. Jesse Bloom, a virus evolutionary biologist at the Seattle Research Center in the United States, has said that BA.5 is more likely to spread than other Omicron variant strains. According to a recent research report released by the Institute of Medicine, University of Tokyo, Japan, compared with Omicron BA.2, BA.5 has a higher effective reproduction number (Rt value), that is, during the infection period, a patient can be infected on average. More people. In South Africa, the Rt value of the BA.5 variant strain is 1.2 times higher than that of BA.2, and according to the estimates of American virologist Trevor Bedford and the research of the University of Tokyo in Japan, the Rt value of BA.2 in South Africa is about 4 to 6. Therefore, the Rt value of the BA.5 variant strain in South Africa is estimated to be between 4.8 and 7.2. That is, an average patient will infect about 5 to 7 people.

Strong immune escape ability.The BA.5 variant is more transmissible in part because of its stronger immune evasion ability. This shows that even if the patient has been infected with other strains of the new crown, or has been vaccinated, BA.5 can still break through this layer of the immune system, resulting in re-infection.

Four sera were analyzed by neutralization assay at the Institute of Medicine of the University of Tokyo, including BA.1 sera from recovered patients (not fully vaccinated), BA.1 sera from survivors of breakthrough infection (completely vaccinated and re-infected), BA.2 Infection with convalescent sera (not fully vaccinated), and BA.2 sudden infection with convalescent sera (completely vaccinated and reinfected). The study found that patients who were not fully vaccinated, even if they had been infected with BA.1 and BA.2, had weaker neutralization of BA.5. In the sera of vaccinated patients, the neutralization of BA.5 was significantly reduced by nearly 2.3 times. For BA.2-infected and vaccinated patients, neutralization was reduced by a factor of 1.6.

Research by the Wellcome Centre for Human Genetics at Oxford University also shows that BA.5 has a strong immune escape ability. Within 14 days of infection with the BA.1 mutant strain, the neutralizing effect of the infected serum on BA.5 was much weaker than that of BA.1 and BA.2, 1.9 times and 1.5 times, respectively; After 21 days of the strain, the neutralization of BA.5 by the serum of the infected person decreased even more, which was 3.4 times lower than that in the face of BA.1, and 2 times lower in the face of BA.2. The same applies to vaccinated patients, and the effects of different vaccines vary.

or more pathogenic.In addition to its strong immune evasion ability, BA.5 may also be more pathogenic than other mutant strains, that is, it is more likely to cause damage to the body of infected organisms. This pathogenicity is reflected in many aspects, including different degrees of influence on its body weight, blood oxygen concentration, bronchi, and alveoli.

According to a report from the Institute of Medicine of the University of Tokyo, based on its research on hamsters, BA.5 is more likely to spread in the lungs and periphery of infected hamsters than BA.2. After 3 days of infection with BA.5 virus, the RNA level around the lungs of hamsters was 5.7 times that of BA.2 virus infection; 5 days after infection, the RNA level of BA.5 was still 4.2 times higher than that of BA.2. Therefore, the BA.5 variant strain is more likely to cause bronchoconstriction or airway obstruction in hamsters. Within a week, hamsters infected with BA.5 were more likely to experience shortness of breath, decreased subcutaneous oxygen saturation, and increased enhanced respiratory intervals. At the same time, the BA.5 mutant strain was also more likely to cause bronchitis, alveolar damage, and lung congestion/bleeding in infected hamsters.

In addition, compared with BA.2 and BA.2.12.1, BA.5 caused a greater decrease in the body weight of hamsters within a week, about 10%, while the body weight of hamsters infected with the remaining strains increased.

Of course, these pathogenicities are only reflected in experimental hamsters and cannot be directly deduced to infected patients, and there is currently no data to directly show that BA.5 causes more severe symptoms.

However, judging from the number of recent hospitalizations and ICU beds in Portugal, the impact of the BA.5 mutant strain cannot be ignored.

According to reports, Eric Topol, director of the Scripps Research Institute (Scripps Research), a medical expert who has been concerned about the new crown epidemic for a long time, said frankly: “BA.5 is what we have seen so far. It is the worst version of the mutant strains ever seen. It takes the already widespread immune escape to a new level and enhances infectivity far beyond what we have seen before with the Omicron mutants.”

Industry experts said that in addition to faster transmission and higher viral load, the new branch BA.5 of the Omicron variant strain has invaded the lungs and has a strong immune escape ability compared with the previous variant strains of Omicron. The new situation may increase the severe rate.

Academician Zhang Boli’s judgment: close contacts of the most infectious strain at present take traditional Chinese medicine for prevention as soon as possible

Academician Zhang Boli said in an interview on July 7: “The recent outbreak of a new epidemic in Xi’an has initiated the most stringent epidemic prevention measures after the Spring Festival this year. It has been confirmed that the virus that caused the epidemic in Xi’an is a new variant of the new coronavirus – strain BA.5 , it is also considered to be the most transmissible strain at present. The latest research results from South Africa show that the R0 value of the BA.5 strain is as high as 18.6, which is the virus with the strongest transmissibility currently known. Recently, a new round of Beijing has been triggered. The virus gene sequencing results of the clustered outbreaks of 2009 show that it also comes from BA.5, which means that the BA.5 strain has been introduced into our country and caused local transmission, and the new situation of this epidemic needs to be taken seriously.”

“The BA.5 strain is not only the most transmissible strain known, but the latest research has found that it has stronger immune evasion and repeated infection ability than the previous strain. The new strain BA.5 has been tested in South Africa, Portugal, the United Kingdom, Israel and other countries are popular, and it is likely to set off a new round of epidemic peaks on a global scale, and my country is facing greater pressure from foreign defense imports.” Zhang Boli said.

How should the Omicron BA.5 variant be prevented?

In an interview with Health Times, Academician Zhang Boli put forward five suggestions: First, people who are close to the BA.5 strain take traditional Chinese medicine for prevention as soon as possible, and should give full play to the accessibility advantage of traditional Chinese medicine in the prevention and treatment of new coronary pneumonia. Second, it is recommended to popularize nucleic acid antigen testing to deal with the spread of new strains. The third is to comprehensively increase the vaccination rate of the whole population, especially the elderly. Fourth, strengthen the efforts to trace the source of dissemination. Fifth, the public is advised not to travel to medium and high risk areas.

Implementing temporary control measures in many places or restarting nucleic acid testing of all staff in Shanghai is rumored to be closed on a large area

Since the outbreak of the epidemic in Sixian, Anhui and other places, local epidemics have occurred in more than ten provinces across the country, and localities have successively adjusted their response measures to prevent problems before they occur.

Lanzhou implemented temporary control measures for a week. On July 10, the Leading Group for the Joint Prevention and Control of the New Coronary Pneumonia Epidemic in Lanzhou City, Gansu Province issued a notice that from 0:00 on July 11, temporary control measures for one week will be implemented in Chengguan District, Qilihe District, Xigu District, and Anning District of Lanzhou City . The press conference on the progress of the new crown pneumonia epidemic prevention and control work in Lanzhou held on July 10 revealed that Lanzhou has carried out two rounds of large-scale nucleic acid screening in the four districts of the main city since 18:00 on July 8.

Haikou implemented 7-day temporary control measures. On July 9, Haikou City, Hainan Province issued a notice: From 18:00 on July 9, temporary control measures will be implemented for 7 days. At the same time, in order to avoid the spillover of the epidemic, from 15:00 on July 9th, personnel in high-risk areas in Haikou have adopted the control measures of staying at home and providing door-to-door services; those in medium-risk areas have adopted control measures such as not leaving the area or picking up items at different peaks; People in low-risk areas leaving Haikou must hold a 48-hour nucleic acid test negative certificate; other islanders must provide a 48-hour nucleic acid test certificate on the basis of checking their health code before they can go through the boarding (ship) departure procedures.

Xi’an implements 7-day temporary control measures. On July 5, the Information Office of Xi’an Municipal Government of Shaanxi Province held a press conference on the prevention and control of the new crown pneumonia epidemic in Xi’an, announcing that from 0:00 on July 6, temporary control measures will be implemented in the city for 7 days. Compared with 0-24:00 on July 5, 1 new local confirmed case and 10 asymptomatic infections were newly reported. At present, the epidemic situation in Xi’an has been basically controlled. Since July 9, many public places in Xi’an have announced that from July 10, dine-in will resume and be fully open.

Nanchang restarts nucleic acid testing for all staff. The New Coronary Pneumonia Epidemic Prevention and Control Headquarters in Nanchang City, Jiangxi Province issued a notice on July 9 requiring that indoor closed places such as KTV, bars, Internet cafes, chess and card rooms, video game halls, mahjong halls, board game rooms, script killings, and escape rooms be suspended. open for business. On July 9, the Nanchang Epidemic Prevention and Control Department issued the “Notice on Carrying out Nucleic Acid Testing of All Staff in a Larger Area in the City”, and will start to carry out nucleic acid testing of all staff in various areas of Nanchang starting from 5:30 on July 10. At the same time, Nanchang Metro will check the health code, itinerary code and negative nucleic acid test certificate within 2 days (48 hours) for passengers entering the station from July 11. Earlier, on June 2, the General Office of the Jiangxi Provincial Party Committee and the General Office of the Provincial Government issued the “Emergency Notice on Adjustment of Epidemic Prevention and Control Measures”. The “Notice” requires that people (including all types of students) can flow freely and orderly between low-risk areas and counties (cities, districts) without local epidemics, no longer check negative nucleic acid test certificates, and no longer carry out nucleic acid landing tests.

Hefei restarts nucleic acid testing for all employees. On July 3, Hefei City, Anhui Province issued the “Notice on Adjusting and Optimizing Current Epidemic Prevention and Control Measures”, and decided to continue the city-wide nucleic acid test for three days, so as to ensure that all the tests should be conducted. Earlier on June 21, the Hefei Epidemic Prevention and Control Emergency Headquarters announced that it would suspend the implementation of free nucleic acid testing in normalized areas once every 7 days.

Nucleic acid testing for all employees in multiple districts in Guangzhou. From the late night of July 9th to the early morning of July 10th, Guangzhou Yuexiu District, Haizhu District, Liwan District, Tianhe District, and Baiyun District successively issued announcements, and on July 10th, nucleic acid testing of all employees in the whole district was carried out.

Hangzhou adjusts the frequency of normalized nucleic acid testing. The Office of the Leading Group for the Prevention and Control of the Novel Coronavirus Pneumonia Epidemic in Hangzhou issued a notice on the 10th that starting from 0:00 on July 11, the frequency of normalized nucleic acid testing in relevant areas of the city will be adjusted from 7 days to 72 hours. Start scanning the code from time to time.

Shanghai will be closed and controlled on a large scale? On the evening of the 10th, some netizens left a message in the “Shanghai Publishing” Wechat comment area: Is the news of a large-scale lockdown next Tuesday true? In response, Shanghai issued a response: From next Tuesday to Thursday (July 12th to 14th), it will cover the whole area of ​​Huangpu District, Xuhui District, Changning District, Jing’an District, Putuo District, Hongkou District, Yangpu District, Minhang District and Baoshan District. Nucleic acid screening will be carried out for all staff in the streets (towns) where there are traces of positive infected persons in other administrative regions. During the screening period, personnel in the above-mentioned areas can show the community (unit, place) with a nucleic acid negative certificate within 48 hours or a nucleic acid sampling certificate within 24 hours.

(Data sourced from the National Health and Health Commission, The Paper, Shangguan News, Health Times, 8:00 Jianwen, etc.)Return to Sohu, see more

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