Tianjin added 40 new positive infections in two days.
Omicron broke through the world's tightest defensive lines, triggering local spread in China for the first time.
Zhang Ying, deputy director of the Tianjin Municipal Center for Disease Control and Prevention, said at a press conference on the 8th that the case has been transmitted for at least three generations and may have been continuously spread in the community for a period of time.
Faced with the Omilon strain, which has already caused a tsunami of cases around the world, Tianjin, with a permanent population of nearly 14 million, is facing a big test.
Li Tong, chief physician of the Department of Respiratory and Infectious Diseases at Beijing You'an Hospital affiliated to Capital Medical University, once told Eight Point Jianwen that the current confirmed cases in Tianjin are likely to be just a branch of the chain of transmission.
Outside Of Tianjin, a locally confirmed case of Aumi Kerong was also found in Anyang, Henan.
In the coming months, the defense lines of China's border crossing cities will be hit by this highly transmitted virus.
The source is unknown, and the final scale may reach several hundred people
This is an outbreak with an unknown origin.
The outbreak occurred in two townships less than 20 kilometers away from Tianjin Binhai International Airport, and neither of the two infected people (a custody class staff member and a primary school student) who was initially identified had a history of living outside Tianjin or in medium- and high-risk areas.
The "custody class transmission chain" in Xinzhuang Town involved at least 11 people: after one staff member was infected, 6 Gaozhuangzi Elementary School students and four students' families who attended the custody class were diagnosed positive.
The "Chain of Transmission of Xianshuigu No. 7 Primary School" continues to ferment in the same class, and a total of 15 primary school students and a family member are currently infected.
Although it is close to Tianjin Binhai International Airport, it is not clear whether the epidemic and the imported strains previously found in Tianjin are of the same source.
The two infected people who "emerged" from this round of the epidemic went to the fever clinic/hospital for nucleic acid testing on their own after the onset of the disease, which also means that the virus has been spread for some time - Tianjin officials believe that it has been transmitted for at least three generations.
Virology expert Chang Rongshan told Eight Points Jianwen that the average transmission speed of Aomi Kerong is 2.7 days in one generation, and three generations are close to 9 days, and the potential scale of this round of epidemic is more than three generations, and he speculates that Aomi Kerong has been secretly spread in Tianjin for 9-14 days.
For the new strain, Aomi Kerong, missing out on the first and second generations of infected people not only means missing the golden window period of 7 days to control the epidemic, but also means that the precise prevention and control strategy based on flow adjustment will be useless.
The more "mild" Aomi kerong is more likely to infect the upper respiratory tract than the Delta strain, causing fever, coughing, and nasal congestion. Li Tong once told Eight Point Jianwen that these "mild diseases" similar to colds make some infected people not take the initiative to conduct nucleic acid testing, and they will carry the Omiljung with an upgraded spread of transmission to cause community transmission, which actually increases the difficulty of dynamic zeroing.
Virology expert Chang Rongshan told eight points of health, the infection period of Aomi Kerong is only 5-7 days, the existing large-scale detection mode is difficult to trace, after the infection period, the infected person has been nucleic acid to negative, relying on our existing nucleic acid detection system is difficult to find a complete chain of transmission, and Aomi Kerong is very easy to spread through the air, no obvious contact between people can be infected, which is almost impossible to trace for most of the city's circulation system.
Jin Dongyan, a virologist at the University of Hong Kong, also believes that "Omilon comes and goes quickly, and during the testing cycle, if the test is not frequent enough and not sensitive enough, it is not surprising that the test was missed."
Nucleic acid screening can not be, the flow of tracking can not catch up, it is foreseeable that in the future period of time, the social cost of high "control + full nucleic acid" is still the main means of prevention and control, and will become more and more frequent.
Image source: Visual China
In view of the characteristics of Aomi Kerong and the development stage of the epidemic in Tianjin, an epidemiologist believes that the scale of the epidemic is still difficult to judge, if the prevention and control is appropriate in the next few days, it may be the Nanjing epidemic model, if the prevention and control in the next week is not lawless, it may be the Xi'an model, hundreds of people, 20 days can not be carried.
Immune barrier test
Since its discovery, Omilon has been regarded as a "big flu" that may end the epidemic because of its low hospitalization rate, low severe illness rate, low case fatality rate, younger infected people, and the expected lack of a run on medical resources.
However, a number of experts told Eight Points of Health, as far as the current data is concerned, these characteristics can hardly be said to be the characteristics of Omicron, and its epidemic characteristics are partly from the differences in the strength of the immune barrier in various regions and populations.
Chang Rongshan told Eight Point Kenwen that South Africa, which was in the summer of the discovery of Aumi Kerong, was not in the high incidence season of infectious diseases, and after the epidemic of a variety of variant strains, the local residents of South Africa had already produced antibodies with higher potency through natural immunity and cross immunity, which made Aomi Kerong the first in South Africa to come to the inflection point.
In the United Kingdom, where the number of infections has surged, Aumicron has not caused the increase in the severe disease rate and case fatality rate, and at a public forum on January 8, Zhang Wenhong, director of the National Center for Infectious Diseases And director of the Department of Infectious Diseases at Huashan Hospital affiliated to Fudan University, said, "The reason is that the new crown vaccination rate in the United Kingdom has reached 80%, the three-shot vaccination rate has exceeded 50%, and there has not been a serious run on medical resources."
For example, if the coverage rate of people over 60 years old is 95%, the coverage rate of 50-60 years old is 80%, and the coverage rate of under 20 years old is only 60%, Omilon will definitely give priority to infecting young people with only 60% vaccination rate, followed by 50-60 years old, and finally 95% of the elderly. Therefore, the rejuvenation of the infected population of Omikerong is not unrelated to the low vaccination rate of young people in Europe and the United States. The child susceptibility it presents is also related to the low vaccination rate of overseas children.
Therefore, Omi kerong is a major test of various immune strategies, including natural immunity, and the immune barrier they form.
For Omikron, the trickier problem is immune escape:
The neutralization trial showed that in the face of Aumechjong, the neutralization capacity of most two-shot vaccines has declined off a cliff. However, in recent days, two articles published in the journal Cell have shown that the third vaccine has a positive effect on the Aumecreon variant. It was explained that while the Omiljung variant could escape vaccine-induced humoral immunity, a third dose of vaccine-induced humoral immunity was able to cross-neutralize the virus.
Chang Rongshan told Eight Point Kenwen that from the perspective of time, the current mainstream vaccine will generally decline in protective efficacy after 3-6 months of vaccination, because from the original strain to Alpha, Delta to Omikerong, the spinous protein of the mutant strain has changed, and the neutralizing antibody produced by the first generation of vaccine and the affinity of the spinous protein of each mutant strain are declining, in this sense, strengthening the needle is essential.
Jin Dongyan called for speeding up the vaccination of the third dose and suggested considering the use of sequential immunization to strengthen the thickness of the barrier.
Therefore, the decoupling characteristics of infection and severe disease presented by Aomi Kerong in Europe and the United States that use mRNA vaccines on a large scale are not necessarily applicable to China, what kind of transmission characteristics can Be produced by Aomi Kerong coming to China, and whether there will be a risk of medical run, the actual experience and performance of the Tianjin epidemic is crucial.
Is it really big flu?
An important feature of Omikeron compared to previous variants is its fastness, which is supported by both the rate of binding to human respiratory cells, the rate of replication, and various relevant epidemiological data. Speed, making it stand out from many mutations and become a new generation of poison kings, this is almost indisputable.
On January 6, the number of confirmed covid-19 cases worldwide exceeded 300 million, and at a press conference on the same day, the World Health Organization pointed out that compared with the previous week, the number of confirmed covid-19 cases in the world soared by 71% last week to more than 9.52 million, the highest record since the outbreak of the epidemic.
In the United States, for the first time since January 3, the number of infections exceeded 1 million in a single day, almost setting a new global peak since the COVID-19 pandemic.
In Europe, on 6 January, the UK reported nearly 180 000 confirmed cases and 231 COVID-19-related deaths, and France reported more than 260,000 cases. The French health minister said that unlike the Delta virus that occupies the ICU, the Aumicron patients are taking up "traditional" beds in hospitals.
This new round of "case tsunami" that continues to spread among countries around the world, the spread of the new strain Aomi Kerong is the "culprit".
The good news about this new strain is that its severe illness rate may not be high.
Studies have shown that Omiljung seems to be more susceptible to upper respiratory tract infection (nasal, throat, and respiratory tract) but less likely to cause more severe lung infections. It is also for this reason that the Omilon virus is more easily transmitted, but it is less likely to cause severe illness that requires being admitted to the ICU and using a ventilator.
In a preprint document released on December 30, an analysis of more than 14,000 infected people from 63 medical machines in the United States from Case Western Reserve University concluded that the proportion of infected people in the Omilon entering the ICU was about 2.6 per thousand, which was 1/3 of the proportion of infected people in Delta entering the ICU (0.78%); the former had a tracheostomy rate of 0.7 per thousand and a 1/6 of the latter's tracheostomy rate (0.43%).
Perhaps, because of this feature, some countries have begun to shorten the quarantine period to abolish it.
From mid-December, the UK Health Security Agency shortened the self-isolation period for some people living with COVID-19 from 10 days to 7 days. On December 27, the US CDC announced that it would reduce the isolation time for asymptomatic infected people from 10 days to 5 days. On January 3, France also announced that it would shorten the quarantine time for infected people who had completed vaccination to 7 days, in addition, Spain, Portugal, Switzerland and other countries also announced that they had shortened the quarantine time.
However, even if there is a decline, the severe illness rate of Omikejong, as indicated by these proportions, is still at a not low level, and there is still a long way to go from the big flu. WHO warns that the deadly Omiljung should not be called "mild", and that the record number of infections can put health systems under enormous strain.
Maybe one day the virus will infect everyone, but that doesn't mean it has to be done now.
From Fauci, the chief infectious disease expert in the United States, to Australian Prime Minister Morrison, policymakers have paid attention to the fact that in the epidemic of Omicron, it is not the record number of cases that should be paid more attention to, but the threat posed by the epidemic to hospitals.
Patients are flocking to the scene, and the scene of medical attrition due to illness is intensifying.
In the UK, the attrition of medical staff due to infection with Omi kerong is becoming a big problem. On January 7, the UK Ministry of Defence announced that it had begun deploying troops to support hospitals facing staff shortages and extreme stress due to the country's record number of COVID-19 cases.
A group of American epidemiologists wrote in the American Medical Journal that Omi kerong explained that the United States' fight against the epidemic needs to enter a "new normal". We must change our strategy to seek coexistence with the virus by balancing its peak, rather than trying to resist it.
In Singapore, which implements the policy of "coexistence with the virus", on January 6, lianhe Zaobao, the largest Chinese-language newspaper in the region, published an editorial saying: Infection data does not have to be the focus of attention, but as far as possible, it is still important to level the case data curve, which requires the cooperation of all Malaysians.
Written by Yu Huanhuan and Shi Chenjin
Li Shanshan and Xu Zhuojun | responsible editors
This article was first published on the WeChat public account "Eight Points Health" (ID: HealthInsight)
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