With more than 2,600 cases in 17 provinces, how long will the multi-point sporadic and one-stop epidemic continue?

As of 24:00 last night, Xi'an alone, since December 9, the cumulative number of confirmed cases has reached 1856; not only Xi'an, the epidemic situation in various places is also unbearable, and there have been local cases in 17 provinces or municipalities directly under the central government, with a cumulative number of 2604 confirmed cases.

On January 1, in Ningbo, starting from a garment factory, an independent epidemic quietly opened, and DNA analysis showed that the strain of the epidemic in Ningbo was highly homologous to the strain sequence of the recent epidemic in Vietnam, and there was a possibility of material transmission.

On the same day, in Henan, an epidemic of unknown origin began in Luoyang, took only 5 days, and the epidemic has spread to 6 cities, with nearly 100 positive infected people (confirmed + asymptomatic).

In this winter, outside the protracted war, the virus has become more rapid and mobile, and the epidemic situation in various places has risen again and again. At the press conference of the joint prevention and control mechanism before New Year's Day, He Qinghua, inspector of the CDC, mentioned that the situation of "local high concentration and multi-point distribution throughout the country" is becoming more and more intense.

There is no doubt that this is the most severe anti-epidemic situation we have faced since The clearance of Wuhan.

A new phase of the outbreak

Sporadic in many places, the source is unknown, and the bottom number is unclear, which has become the characteristic of new outbreaks.

Henan, once again hit. As of January 5, the epidemic in Henan has involved six cities in Luoyang, Xuchang, Zhengzhou, Zhoukou, Gushi and Shangqiu, with a total of 54 cases of indigenous infection reported. The transmission relationship between the six cities is still unclear, and the source of the epidemic has not yet been announced.

The case in Henan initially appeared in Shenqiu County, Zhoukou City. Previously, four people doing business in Xi'an were diagnosed with the infection after driving back to Shenqiu, and they had passed through the Lingbao service area of the Lianhuo Expressway. An infected person in Luoyang also stayed in the same service area.

In addition, judging from the circulation information released by Xuchang and Zhoukou, there may be a time-space overlap between the infected people in the two places. Among them, 2 infected people reported by Xuchang Yuzhou City worked at the local Eurasian Ceramics Co., Ltd. Two days later, Zhoukou Taikang County reported a couple of infected people, who had also gone to eurasian ceramics company to load goods.

At present, it can be clear that the source of infection in Gushi and Shangqiu points to Zhengzhou, and Zhengzhou has preliminarily identified three transmission chains of card friends, funeral feasts and families. As of the 5th, Zhengzhou has identified a total of 161 people and 335 people.

What is worrying is that in the epidemic in the 6 cities of Henan, many of the first infected people found have no history of living outside.

For example, 2 infected people who worked at Eurasian Ceramics in Yuzhou City did not go out for 14 days. One of the first infected people found in Zhengzhou city is a cleaning staff of a hotel in the airport area, and has been working in the hotel for many consecutive days. Does this mean that the virus has been circulating in the community for a long time?

After the discovery of 2 infected people, Yuzhou City, with a population of 1.1 million, quickly declared a lockdown. Similar to Xi'an, Yuzhou's transportation system was completely suspended overnight, and all shopping malls and supermarkets except "ensuring the supply of daily necessities" were suspended.

But the number of cases in Yuzhou continues to rise. As of 24:00 on January 4, a total of 9 confirmed cases and 23 asymptomatic infected people have been reported in this round of the epidemic in Yuzhou.

In addition to Henan, Ningbo, Zhejiang Province, once again broke out during the New Year's Day holiday, and it had nothing to do with the previous "Shaohang-Ningbo" epidemic.

As of January 5, a total of 29 new confirmed cases were reported in Beilun District, Ningbo, 25 of which were from the same department of the same company, "Shenzhou Knitwear".

The person in charge of the Zhejiang Provincial Center for Disease Control and Prevention said at a press conference that the strain of the epidemic in Ningbo is a Delta variant strain (AY.57 evolutionary branch), which has a high homology to the sequence of the recently circulated strains in Vietnam, and there is a possibility of material transmission to human.

According to China News Weekly, Shenzhou International, to which Shenzhou Knitting belongs, is the largest knitted garment export enterprise in China, with a fabric base and a garment factory in Vietnam. However, it is worth noting that the epidemic in Beilun District did not come from the ports in the region, but was concentrated in the workshop of the knitting factory.

Therefore, the epidemic in Ningbo looks within the controllable range, but the source of transmission is still a mystery.

From a national perspective, the new crown epidemic has shown a new trend: the density and breadth have increased significantly, and the scale of the impact has also expanded.

Since December 9, when the epidemic began in Shaanxi, according to the data released by the National Health Commission, 17 of the 34 provinces, municipalities and autonomous regions in the country have had locally confirmed cases, and the cumulative number of confirmed cases nationwide has reached 2604.

In 2020, large-scale epidemics are basically concentrated in autumn and winter, with an interval of 2 months or even longer, but since the arrival of Delta strains in May 2021, the frequency of epidemics has increased significantly, and there will be more than one large-scale outbreak every month, and in some months, there are even 2-3 outbreaks of more than 100 people, almost "looping". Moreover, the previous wave of the epidemic is not over, and the next wave is reignited, and there is almost no time for respite.

There are even independent, sporadic outbreaks in many places at the same time. Since the first case of infection was reported in Shaanxi on 9 December last year, there have been at least seven outbreaks of independent transmission.

From the perspective of scale, after May 2021, a large-scale epidemic of 100 people has become the norm, and the epidemic in Xi'an has become the most serious one after the lockdown in Wuhan, with more than 150 new cases per day for 7 consecutive days, and the daily growth even exceeds the total number of confirmed cases of previous single rounds of epidemics.

The time to clear zero is constantly extending. The epidemic in Xi'an has been nearly 1 month, and there is still double-digit growth every day.

From the perspective of the source of the epidemic, although there was an ultra-long inter-provincial transmission chain before, the results of the traceability of the circulation were relatively clear. At present, there are more and more untraceable sources of the epidemic. This is the case of Yuzhou, Zhengzhou and Ningbo in Henan.

From dynamic zeroing to social zeroing

Since December 22, Xi'an announced that the city's communities (villages) and units have implemented closed management, and after more than 10 days of lockdown, Xi'an's daily growth has still exceeded 100 people, and in the case that the epidemic is still not under control, Xi'an has proposed that it must achieve the new goal of zero social clearance.

On the afternoon of January 5, Xi'an Held a Press Conference on Epidemic Prevention and Control, at which it was pointed out that from the situation of the last three rounds of nucleic acid screening, the total number of cases showed a downward trend, which was found in the isolation and control of personnel and the sealing and control areas, and the social surface was basically cleared.

Chen Zhijun, deputy director of the Xi'an Municipal Center for Disease Control and Prevention, previously explained that "social clearance" refers to the fact that all new confirmed cases found later are in the isolated close contacts or close contacts of close contacts, and there is no longer a community-based spread of the epidemic.

In fact, the social zero is the zero outside the communication chain, and there is no hidden communication chain at the social level to continue to be active. An epidemiologist told Eight Point Jianwen, "The purpose of social clearance is to open up as soon as possible, there is no way, xi'an prevention and control pressure is too great, and the cost of secondary disasters is too high." ”

Image source: People's Vision

In China's urban epidemic prevention, between precision prevention and control and national nucleic acid, different cities have made different choices according to the gap between their public health and urban management capabilities. However, since the autumn and winter of this year, there have been outbreaks of multi-point sporadic epidemics in many cities, often the source of infection is unknown, and there is no obvious epidemiological link between multiple transmission chains, and even dozens of rounds of national nucleic acids cannot find all cases.

Xi'an can only "lock down the city", but Xi'an in the lockdown for a week, after multiple rounds of nucleic acid, the epidemic has not yet ushered in an inflection point, in order to adjust the city's next step of prevention and control measures, and even unseal to create conditions, Xi'an is the first time to put forward the goal of "social clearance", it can also be seen that the pressure on the epidemic prevention system is increasing, and Xi'an has also paid a huge price for this.

Zeng Guang, a member of the high-level expert group of the National Health Commission and a former chief scientist of epidemiology at the Chinese Center for Disease Control and Prevention, pointed out in an interview that the epidemic in Xi'an is the most serious one after Wuhan, "What happened in Xi'an today may happen in other cities in the future." ”

He also said that the epidemic in Xi'an shows the characteristics of multi-point and hidden outbreak, and how to control it in the short term in the case of out-of-control in the early stage of the epidemic, hoping to precipitate new epidemic prevention experience.

A number of interviewed experts told Eight Points That after the epidemic in Xi'an, the domestic epidemic prevention and control may enter a new stage, and under the general policy of adhering to zero, the overall tightening trend is tightening. For example, after Xi'an, Yuzhou, Henan Province, declared a lockdown after two cases were detected.

Can our covid-19 defense line protect against Aumicron?

In addition, the Omiljung strain, which is causing a tsunami of cases around the world, is a serious challenge for China, and our epidemic prevention system has been slightly struggling to face the Delta strain. In the face of the faster spreading Ofmicron mutant strain, can the existing prevention and control system still resist?

At present, many ports in China have found imported cases of Omikerong. It is only a matter of time before many respondents predict that Aumechjong may penetrate the first line of defense for foreign imports and trigger local spread.

Moreover, under the strategy of dynamic zeroing in China, there are very few cases of Delta infection, and once the Aomikron strain is introduced, it will soon replace Delta and become the mainstream epidemic strain in China. A number of experts also appealed to Eight Points Kenwen that it is now necessary to make a plan and prepare to deal with the new strain.

For example, the previous domestic prevention and control system, which has established a closed loop of overseas input management, and the standard of 48-hour nucleic acid antibody double yin in medium- and high-risk areas, may have to re-evaluate its effectiveness when facing new strains.

"Judging from the current situation in Xi'an, the prevention and control system has shown vulnerability in dealing with the Delta strain, and in the future, in the face of new strains, the prevention and control system will definitely increase its means and change its methods." Virology expert Chang Rongshan, for example, how often to do nucleic acid testing in isolation places, should re-evaluate the plan.

At present, according to public information, the isolation site does a nucleic acid test on the 1st, 3rd, 7th, 10th and 14th days of isolation, a total of 5 times, "for Omikron, the interval is too long." Because the new strain spreads faster, the data now is that the average incubation period is only about 2.7 days, and it can be tested positive. And once it reaches the city, the efficiency and quality of the existing national nucleic acid testing are difficult to keep up with the speed of virus transmission. ”

Rapid testing is very critical, so Chang Rongshan suggested, "The use of rapid, home-based antigen testing will be a weapon to deal with Omi Kerong." ”

Lu Mengji told Eight Points Kenwen, "From the experience of various countries, the impact of Omi Kerong on society is very different. Countries, including Germany, are adjusting their regulations. Insisting on zeroing out will be more difficult or will require a greater cost to achieve. ”

In the face of the general concerns about the introduction of Aomi Kerong, Liang Wannian, head of the expert group of the National Health Commission's Leading Group for Epidemic Response and Handling, responded in an exclusive interview with the surging news that "dynamic zeroing" is the best choice and general policy for epidemic prevention and control at this stage.

Written by Zhu Xueqi and Shi Chenjin

Li Shanshan and Xu Zhuojun are responsible for editing

This article was first published on the WeChat public account "Eight Points Health" (ID: HealthInsight)

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