Source 丨21 Healthnews21 original work
Author 丨 Wei laughs
Editor 丨Xu Xu
Image source 丨 Figureworm
The Spring Festival is approaching, and at present, the domestic new crown epidemic is spread at many points, superimposed on Omicron , and the epidemic prevention and control situation is severe and complex.
On January 8, Tianjin testing found 2 infected people in Omiclon. In addition, the Aomi Kerong mutation also spread to Anyang, Henan. On January 10, Anyang City, Henan Province, reported that two cases of positive local nucleic acid were found in the active test population.
According to the analysis of the Tianjin Municipal Center for Disease Control and Prevention, the two indigenous cases of the new coronavirus belong to the VOC/Omicron strain (BA.1 evolutionary branch) and belong to the same chain of transmission.
In addition, according to anyang Daily, the circulation survey shows that the anyang case in Henan and the local epidemic in Tianjin belong to the same chain of transmission, both of which are Omicron. Combined with the results of epidemiological investigation and gene sequencing, the source of infection of this epidemic in Anyang City was basically identified as a college student who returned to Tangyin County of Anyang City from Jinnan District of Tianjin City on December 28, 2021.
This is the first time since December 13 last year that the new coronavirus Has been detected from the entry of the New Coronavirus Semikron mutation, and the first time that the local inter-provincial transmission chain of TheOmilon has been detected.
On January 10, Zhang Boli, an academician of the Chinese Academy of Engineering, said in an interview with the media that the Tianjin epidemic is the first time that the Aomi Kerong variant has spread in China's local community, and the virus is indeed very contagious, but the symptoms are not obvious, the concealment is also strong, and it is easier to spread or concentrate on outbreaks.
In this regard, Lu Hongzhou, a well-known infectious disease expert and president of the Third People's Hospital of Shenzhen, also told the 21st Century Business Herald reporter today that the study confirmed that the transmission capacity of Omicron was about 2-3 times higher than that of Delta, but the symptoms of clinical diseases were mild. It is precisely because Omi kerong is milder than other variants that some people describe Omiljung as a "natural vaccine".
Professor Ian, a virologist at the University of Reading in the United Kingdom, and Nachman Ash, a senior official of the Israeli Ministry of Health, agree with this view, believing that because Omilon is highly contagious, but milder than other variants, antibodies can be produced without causing severe illness, improving immunity to other virus strains, and forming herd immunity.
But there are also experts who have different views on this. As Luis Ostrosky, director of the Department of Infectious Diseases at McGovern School of Health Sciences in Texas, pointed out that the biggest problem of herd immunity is time and effectiveness, antibodies will decline over time; in addition, antibodies produced after infection with Omilton are not necessarily effective in preventing other virus strains.
In fact, the antibodies produced after infection with Omikejong are not very effective against Omikejong itself. Lu Hongzhou proposed that the phenomenon of "immune escape" in Aomi Kerong is more significant.
For the Aomi Kerong mutant strain, how should we do a good job in scientific prevention and control measures? Many experts in China said that we must develop specific vaccines based on mutant strains of spike mutations, especially vaccines against Omi kerong. Early vaccination of booster vaccinations is also critical.
Omi kerong was the first in the country to spread across provinces
On January 10, according to the Tianjin Health Commission, from 0:00 to 24:00 on January 9, There were 21 new confirmed cases of local new coronary pneumonia in Tianjin, all in Jinnan District.
On January 8, Tianjin found 2 cases of positive nucleic acid tests. According to the Tianjin Epidemic Prevention and Control Command, after analysis and comparison, and confirmed by the Chinese Center for Disease Control and Prevention, the two indigenous cases of the new coronavirus in Tianjin belong to the VOC/Omicron variant (BA.1 evolutionary branch).
In addition to Tianjin, the Aomi Kerong mutation also spread to Anyang, Henan. On January 10, Anyang City, Henan Province, reported that two cases of positive local nucleic acid were found in the active test population.
According to the report, on January 8, Anyang City, Henan Province, screened and found 2 cases of positive nucleic acid of the new crown virus in the active test population. On 9 January, genome sequencing revealed that the two indigenous cases were infected with the ba.1 branch of the Aomi Kerong variant, which belonged to the same transmission chain as the existing local epidemic in Jinnan District, Tianjin. According to epidemiological investigations, the source of infection in the current outbreak in Anyang City was a college student who returned from Jinnan District of Tianjin City to Tangyin County of Anyang City on December 28, 2021.
"Aomi Kerong is more contagious than the previous Delta, and the current epidemic in Tianjin is also manifested as a high proportion of young infected groups such as primary and secondary school students, which is also a new feature of the Aomi Kerong mutated strain, which deserves our high vigilance and response." Academician Zhang Boli pointed out.
Up to now, there have been 5 imported cases of Aumechjong in Tianjin, Guangzhou, Changsha, Shenzhen and Zhejiang, except for Guangzhou, which have not caused local infections. The imported case of Guangzhou Aomi Kerong was found positive during the home isolation period after the end of centralized isolation, causing 3 cases of infection among people living in the same building. The current round of the epidemic in Tianjin is by far the largest number of local infection cases caused by Aomi Kerong in China.
The Omikejong variant also spread rapidly abroad. According to the relevant report of the US Centers for Disease Control and Prevention, after the new confirmed cases reached 1 million on January 3, the average daily new cases in the United States reached 491,700 in seven days, and the average of these seven days almost doubled from a week ago.
However, U.S. Center for Disease Control and Prevention Warrensky said in an interview on the 7th that the heating up of the epidemic caused by Omicron has not yet reached its peak. "In other countries like South Africa, the way the peak was that there was a rapid decline in new cases, but I don't think we've seen that peak in the United States."
Why is Omi kerong called a "natural vaccine"?
Some self-media said that Aomi Kerong caused a "big flu", in this regard, Zhang Wenhong, director of the Department of Infectious Diseases of Huashan Hospital affiliated to Fudan University, recently said at a public forum: "This is not enough evidence." ”
Zhang Wenhong pointed out that Aumi Kerong was only discovered in November and has already ravaged the world in just a few months, resulting in a surge in infections in many countries and regions. Omikeron is a "biting" strain.
Lu Hongzhou also pointed out to the 21st Century Business Herald reporter that the study confirmed that the communication ability of Aomi Kerong was about 2-3 times higher than that of Delta. From a molecular mechanism point of view, compared to the original strain, Omi kerong contains mutations, deletions or insertions of more than 60 amino acids, of which more than 50% (34) are located on spike proteins.
Lu Hongzhou said that because the binding of the virus's spike protein and target cell ACE2 mediated the infection of 2019-nCoV, he speculated that a large number of mutations on the Omicron spike protein were the genetic basis for its high infectivity. In addition, studies have shown that mutations in G339D, N440K, S477N, T478K, Q498R and N501Y on the Omikejong RBD enhance their binding affinity with human ACE2 receptors, and combinations such as Q498R and N501Y can additionally enhance binding to ACE2.
What are the symptoms of infection with Omi kerong? The ZOE COVID-19 app has summarized 19 common symptoms of Omi kerong by collecting data from 4 million users from around the world. Runny nose is the most common symptom, affecting nearly 73% of patients with coronary disease, followed by headache (68%), fatigue (64%), sneezing (60%) and sore throat (60%).
It is worth noting that Academician Zhang Boli pointed out that although the Infectivity of the Omicron variant has increased, many overseas clinical observation studies have shown that its toxicity has weakened, manifested as more asymptomatic people, lighter lung damage, and fewer serious patients. "Of course, we are closely observing and summarizing the situation of the epidemic situation in Tianjin."
Why is Omiljung more contagious but less clinically mild? In this regard, Lu Hongzhou told reporters that Aomi Kerong is more inclined to infect people's upper respiratory tract, and the in vitro experimental study from Hong Kong shows that The replication rate of Aomi Kerong in the human bronchi is 70 times faster than Thatta, and the replication rate in human lung tissue is 10 times slower than Thatta, which may be one of the reasons for the low degree of inflammation of the disease.
Lu Hongzhou further pointed out that in addition to being highly sensitive to the upper respiratory tract, The Ability of Omikeron to respond to cellular interferon is reduced, which provides a potential mechanistic explanation for the clinically observed lower pathogenicity of Omikeron. The immunomodulatory NF9 peptide in the spike protein-specific core of Omiqueron was not significantly affected, a result that further demonstrated that Omilon was less pathogenic than other VOCs.
It is precisely because Omilon is milder than other variants that some have described Omilon as a "natural vaccine."
Professor Ian, a virologist at the University of Reading in the United Kingdom, agrees with this view, pointing out that because Omilon is highly contagious but milder than other variants, antibodies can be produced without causing severe illness, improving immunity to other strains of the virus and forming herd immunity.
French Health Minister Verand also said that France and some countries with similar infection rates are about to achieve herd immunity, and the dawn of the end of the epidemic has emerged. France is currently in the midst of a fifth wave of the outbreak, and its judgment is likely to be the last wave. "Judging by the infection rates in France and some other countries, it is likely that we have acquired some form of immunity through vaccination or infection."
Nachman Ash, a senior official in the Israeli Ministry of Health, also pointed out that the widespread spread of Omi Kerong in Israel is likely to form a herd immunity.
But some experts disagree. For example, Luis Ostrosky, director of the Department of Infectious Diseases at mcGovern School of Health Sciences in Texas, pointed out that the biggest problem of herd immunity is timeliness and effectiveness, and antibodies will decline over time. Moreover, antibodies produced after infection with Omiqueron are not necessarily effective in preventing other strains of the virus. "Pinning hopes on herd immunity is high risk. The widespread presence of infection means that a large number of hospitalizations can occur, leading to the collapse of the health care system and the death of a large number of people. ”
In fact, the antibodies produced after infection with Omikejong are not very effective against Omikejong itself. Lu Hongzhou proposed that the phenomenon of immune escape in Omicron was more significant. The study found that Omiljung did not increase the risk of initial infection in the population, but it increased the risk of re-infection. In the 2nd and 3rd peaks, dominated by Beta and Delta, the hazard ratios for repeated infections were 0.75 and 0.71, respectively. In South Africa's recent 4th peak, dominated by Omilon, the hazard ratio of its repeated infections rose to 2.39, which means that the immune escape phenomenon of Omiljung is more significant.
Gregory Poland, director of vaccine research at Mayo Medical Center, also pointed out that as long as the new crown virus continues to mutate, there will be no permanent immunity. "If there is a new mutant virus that can completely escape the current antibody, we have to start over."
How to scientifically prevent and control Omi kerong?
For the Aomi Kerong mutant strain, how should we do a good job in scientific prevention and control measures?
Numerous studies have shown that current COVID-19 vaccines are not as effective against the Omicron variant as previous VOCs. Therefore, Lu Hongzhou pointed out that we must develop specific vaccines based on mutant strains of spike mutations, especially vaccines against Omilon. Studies have also demonstrated that infection with Omikeron can induce a wider range of neutralizing antibodies that can be used to immunize other variants of 2019-nCoV. Since the current vaccine has a weak impact on Omilon, the development of a Omilon targeted vaccine is urgent and beneficial to combat all current strains of the new crown virus.
Zhang Boli also said that it is necessary to step up the development of a vaccine against the Aomi Kerong variant and carry out basic research on the mutation law of the new crown virus.
It is worth noting that Chamberlain also pointed out that although the protective power of vaccines has declined, it is still effective in preventing severe diseases. The results of the current study show that the vaccine is still very effective in preventing the transition to severe illness and mortality, and the effective rate can reach 80% to 90%. Therefore, it is still necessary to strengthen the vaccination of vaccines and increase the coverage of vaccines. "If there are no special circumstances, people should be vaccinated as soon as possible."
Lu Hongzhou also told reporters that the vaccination of vaccine reinforcement injections should be carried out as soon as possible. "Recent studies have found that most patients with Omilon breakthrough infection have no signs of severe COVID-19, which is closely related to the antibodies produced after the previous full vaccination, and further studies have found that in the serum after vaccination, T cells and Omiljung cross-reactions were found. The findings re-emphasize the importance of early full vaccination in populations to build herd immunity, especially in developing countries. ”
Optimistically, studies have shown that broad-spectrum neutralizing antibodies targeting the conservative epitopes of the 2019-nCoV variant, such as the monoclonal antibodies BRII-196 and BRII-198 that have been listed in China, are the key to containing and treating Omikejong. "Although there is still much room for improvement in drug and antibody treatment strategies against Omikejong, their therapeutic efficacy has been demonstrated in previous studies."
In addition, Lu Hongzhou pointed out that the existing public health measures are effective, and timely diagnosis and physical isolation are the most effective ways to cut off transmission. "At present, the detailed characteristics of the Omicron mutant strain are becoming clearer and clearer. Given that the same mutations were observed in the spike proteins in previous VOCs, this suggests that current public health measures, including ventilation, safe distancing, frequent hand washing, and wearing masks, are also effective against the Opichron variant. Similar to previous VOCs, timely diagnosis and isolation are important to cut off the spread of Omikeron. ”
On January 8, at the press conference held by the joint prevention and control mechanism of the State Council, Mi Feng, spokesman of the National Health and Health Commission, also introduced that it is necessary to continue to adhere to the general strategy of "external prevention of import and internal prevention of rebound" and the general policy of "dynamic clearance", and to ensure that it should be inspected and inspected, isolated, and treated as soon as possible, and the social spread of the epidemic should be blocked as soon as possible.
Liang Wannian, head of the expert group of the National Health and Health Commission's Leading Group for Epidemic Response and Handling, also told the media that we do not yet have the ability not to have a local case, but we have the ability and confidence to quickly extinguish the epidemic when local cases are found, and we are not pursuing "zero infection", but pursuing the fight against the epidemic as soon as possible.
Zhang Boli stressed that the current situation is still grim, the problem of the Aumi Kerong mutation strain needs to be highly vigilant, strictly prevent overseas imports, prevent people and objects, especially the port city and cold chain freight links are the top priority, which is the key to curbing the spread of Omi Kerong.
"If we take scientific prevention and control measures, we can win the war against COVID-19." Lu Hongzhou said.