After experiencing more than 1,000 infections in a single day for 5 consecutive days, Shanghai has once again upgraded its epidemic prevention and control policies.
On the evening of March 27th, the Shanghai Leading Group for the Prevention and Control of the New Coronary Pneumonia Epidemic issued a notice that it will follow the principle of stubbing and advancing, with the Huangpu River as the boundary Implement sealing and control and nucleic acid screening in batches.
Stubble suppression is a term used in northern agriculture. Simply put, it means planting crops one after another to prevent the land from being idle.
The first batch, Pudong, Punan and adjacent areas will be sealed and controlled first, nucleic acid screening will be carried out, and the block will be lifted at 5:00 on April 1. At the same time, key areas in the Puxi area continued to implement closure and control management.
The second batch, from 3:00 on April 1st, the Puxi area will be closed and controlled, and nucleic acid screening will be carried out, and the closure will be lifted at 3:00 on April 5th.
In Shanghai, where the epidemic lasted for a month, under the severe situation, the pause button was finally pressed in the form of half-city and half-city sub-regions. The anti-epidemic boots in Shanghai, which have attracted the attention of the people all over the country, landed.
Shanghai Mode for Precise Prevention and Control
Why didn’t it work this time?
Shanghai is a model city of anti-epidemic. “Precision prevention and control” and “grid management” have curbed the spread of previous local epidemics at the least cost, and achieved anti-epidemic and maintenance. The balance of economic operation. This is something that many cities cannot do.
The nucleic acid detection under the Disney fireworks is the highlight of Shanghai’s anti-epidemic moment
Image source: Pudong Branch of Shanghai Public Security Bureau
In this round of epidemic, Shanghai has many similarities with Shenzhen, another mega city. The main pressure it faces also comes from the import of Hong Kong, but the prevention and control measures adopted are different, showing different symptoms. development changes.
Image source: Made by myself
Two similar cities, close to the initial level of the epidemic, ran out of completely different development curves. By March 28, the daily number of newly infected people in Shanghai was 500 times that of Shenzhen.
Shenzhen community personnel who came for inspection during the lockdown period
Photo source: Xinhua News Agency
In addition to the large number of local infected people in Shanghai, there is also a spillover from the epidemic. Shanghai-related cases have appeared in many parts of the country, and tragedies such as the death of a nurse due to hospital closures and delays in treatment have caused many people to criticize Shanghai’s fight against the epidemic recently.
And now that the lockdown has finally started in half the city, is the “anti-epidemic top student” not a good student?
Why was the precise prevention and control and grid-based meticulous management effective at that time, but failed to control the spread of the epidemic today?
Because the virus opponent has evolved, it is difficult to win today’s battle with the original approach.
The main opponent of this round of epidemic is already the mainstream Omicron BA.2 evolution strain in the world. BA.2 is one of the most infectious viruses known.
The inherent infectivity of a virus is measured by the R0 indicator, that is, when the population is not immune or protected, an infected person can infect several people. The higher the R0, the more contagious it is.
BA.2 is still a new virus strain, and it will take time to calculate the specific R0. Judging from the current estimated data, it is already the top level. The WHO’s former infectious disease expert’s estimate is 12, and Shanghai’s estimate is 9.5, which is much higher than the original strain of the new crown and the previous mainstream delta strain, and it is also much higher than the ordinary Omicron.
Without protection, one infected person can easily infect as many as 10 others.
In addition to being extremely contagious, BA.2 has a shorter incubation period than both the previous original strains and variants of the new coronavirus.
The incubation period of the original strain of the new coronavirus is about 5.1 days, 4.4 days for Delta, and 3.0 to 4.2 days for ordinary Omicron.
Strong infectiousness and short incubation period are not conducive toHumans find the virus through nucleic acid testing. If the source of infection cannot be controlled, it will be difficult to contain the spread.
The shorter the incubation period, the more difficult it is to detect nucleic acid. In extreme cases, when the infected person gets a positive result, the virus has already spread. And because it is highly contagious, it will spread to more people.
When protective measures cannot be deployed faster than the virus, loss of control is inevitable.
This milk tea shop in Shanghai was once dubbed the least risk area
Image source: CCTV
Setting small risk zones is also a Shanghai experience, praised for having little impact on life. But the premise that this setting works is that the virus spreads slowly and can be blocked in a small milk tea shop in time.
Now, that doesn’t work.
Why are there so many asymptomatic infections in Shanghai?
Friends who are concerned about the epidemic data may have discovered that there is another feature of this round of epidemic in Shanghai: there are many asymptomatic infections.
In the past few days, asymptomatic infections can account for 99.7%.
Asymptomatic infection is a unique diagnosis in China in the new crown epidemic. In the “New Coronavirus Pneumonia Prevention and Control Plan”, asymptomatic infections are defined as follows: positive for the etiological test of the new coronavirus and no relevant clinical manifestations, such as fever, dry cough, fatigue, sore throat, and decreased sense of smell (taste) Patients with self-perceived or clinically identifiable symptoms and signs such as diarrhea, and CT imaging without imaging features of new coronary pneumonia.
Asymptomatic infections are not fixed. Some people are infected with the new coronavirus and have no symptoms at all, but some people are only in the early stage of symptoms when they are tested, and symptoms will occur after a few days. still to appear.
Asymptomatic people are also infected with the new coronavirus and are also at risk of transmission.
There are three possible reasons for the large number of asymptomatic infections.
1. The virus itself changes.
BA.2 is more contagious and has a shorter incubation period, while its pathogenicity is also decreasing, and the probability of being permanently asymptomatic after infection increases. Coupled with widespread vaccination, people infected with BA.2 are more likely to become asymptomatic than when they were previously infected with the original strain, Delta.
2. Better detection capability.
The better the detection capability, the more proactively it can find those who have just contracted the virus, and the more pre-symptomatic people there are. With the progress of the epidemic, nucleic acid testing will cover more comprehensively, and asymptomatic infections will naturally increase.
The rate of asymptomatic infections has also increased in Jilin Province at present
Image source: Jilin Provincial Health Commission
3. Subjective judgments vary.
The judgment of symptoms is not as clear as the indicators. How can it be regarded as clinical manifestations, and the doctor’s guidance for consultation is very important; what is regarded as CT has characteristic changes, which can also be affected by human factors. The attitude of doctors in different regions to diagnose affects whether infected people are classified as confirmed or asymptomatic infection.
In the early stage of the epidemic, it is of certain value to establish a diagnosis of asymptomatic infections, and it is possible to focus on those diagnosed with more transmissibility. But today, when the virulence of the virus has weakened and vaccines have gradually become popular, such a judgment influenced by human factors is still used, which may confuse the public or even relax their vigilance.
It is time to consider appropriate adjustments to the judgment and management of asymptomatic infections.
Shanghai Epidemic Forecast:
Peak in next few days
We won’t see a drop in the number of infections following the half-city lockdown right away, but will likely peak gradually over the next few days.
Compare Shenzhen. Shenzhen spent a week of “pause” in exchange for epidemic control, and social dynamics were cleared. Shanghai may not be so fast.
Comprehensive prevention and control is the main means to control the epidemic, and the effect will definitely be seen after a certain period of time. Shanghai’s half-city closure and control this time also adopted quite strict measures. In the sealed-off area, the residential area is under closed management, and all people stay at home, and only people and vehicles can enter or leave; public transportation, subways, ferries, taxis, and online car-hailing operations are suspended; all enterprises implement closed production or work from home .
However, the timing of the lockdown was significantly later than that in Shenzhen, and the preparations made before were less than the pre-closure stage in Shenzhen.
Shanghai has been pursuing for a long time to screen slowly at a small price. It was really unable to withstand the pressure to start the closure and control, and it has missed the best time for community transmission control. It will not be able to control the peak as quickly as Shenzhen.
We will see daily confirmed and asymptomatic infections in Shanghai continue to remain high for a period of time until the majority of those infected are found and placed in quarantine.
It is very likely that the current wave of the Shanghai epidemic will last until the end of April and early May.
Lessons from the Shanghai Model
Has Shanghai failed in its fight against the virus in the past month?
If you look at the current number of infected people and the lockdown measures that have to be increased, Shanghai’s anti-epidemic exploration is indeed unsuccessful.
Policy makers must know that early closure and control is more conducive to obtaining good numerical results, but at the same time, they also hope to explore a more suitable path for fighting the epidemic today. In the face of a virus that has changed, it is still the same as the previous route. It can only stay where it is, but it will bring secondary harm instead of scientific anti-epidemic.
Shanghai, made a difficult attempt to find a balance between as few omissions as possible and minimal cost to life. This effort, whether it succeeds or fails in the end, the experience and lessons will belong to the whole of China.
This month, Shanghai told us that if the virus continues to maintain such contagiousness and virulence, it is necessary to do so in order to achieve the lowest cost and lowest social cost to win the battle against the epidemic.
1. Identify outbreaks more quickly
Shanghai’s first batch of antigen self-test kits are on sale
Data source: Xinmin Evening News
When the virus spreads silently and rapidly in an area, it is necessary to carry out simpler rapid detection and accurate nucleic acid detection to detect changes in the spread of the epidemic more quickly and respond more quickly.
2. Accurate and reasonable allocation of medical resources
Shanghai has one of the most abundant medical resources in China, but in the past month, we have seen a lot of insufficient medical resources. When there are a large number of asymptomatic and mildly infected people, it may be unnecessary to close the hospital and dispatch a large number of medical staff to deal with them. This will affect normal medical needs and bring secondary damage from medical runs.
According to the requirements of the new domestic treatment guidelines for new coronary pneumonia, it is an effective measure to focus on the characteristics of the current virus to centrally isolate and manage mild and asymptomatic managers of new coronary pneumonia outside the hospital.
At the same time, the medical grading system should be improved. If more family doctors serve as buffers between large hospitals and patients, they can grade and refer serious diseases to large hospitals faster and more accurately, and there will be no waste of medical resources.
Image source: Message from Lilac Garden WeChat public account
3. Control slows the spread of the virus
BA.2 has a very high R0 and can infect more people. But after some interventions, such as universal vaccination against the new crown, to reduce the infection, can delay the interruption of this rapid spread.
China’s current vaccination rate is already very high, and the situation of insufficient vaccination of the elderly and the need to improve vaccine technology can also be solved in the future. See: When will this round of epidemic end? One thing is very important!
Any kind of epidemic prevention method has a price, the only difference is what the cost is and how we can reduce the cost scientifically.
Thanks to the medical and people’s livelihood support forces from all over Shanghai. Come on Shanghai!
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