In-depth attention | Be wary of "breaking defense"
Chai Yaxin Li Yunshu
Nanjing is still "tracing the roots", and Zhangjiajie has attracted attention again.
The epidemic that started at Nanjing Lukou International Airport has spread to many provinces and cities including Anhui, Sichuan, Hunan, Guangdong, and Chongqing.
Among them, reports on the circulation trajectory of confirmed cases in Zhangjiajie, a popular tourist destination, have become the focus of the spread of the Nanjing epidemic.
The imported epidemic has exposed loopholes in the prevention and control of the airport epidemic, and the domestic transmission cases associated with this have revealed new spread risks.
The situation is worrying, and it also raises questions: Why did this epidemic originate?
What problems are exposed?
In the face of the more transmissible delta virus, does the vaccine play a role?
What else can we do?
The number of infected people continues to increase, and screening in many places reveals that the infected people are converging in Zhangjiajie
Except for the cases in and directly related to Nanjing, cases without history of residence in Nanjing have appeared one after another in recent days.
At the 227th press conference on the prevention and control of new coronavirus pneumonia in Beijing, Pang Xinghuo, deputy director of the Beijing Centers for Disease Control and Prevention, introduced that from 0:00 on July 28 to 12:00 on July 29, Beijing added 2 new cases. The confirmed cases of new coronary pneumonia associated with the foreign epidemic are all returnees from Zhangjiajie, Hunan.
Not only Beijing, but also Chengdu in Sichuan, Dalian in Liaoning, Changde in Hunan, and many other places have reported cases of infection that have not been to Nanjing, and their trajectories all point to Zhangjiajie.
On July 26, Dalian platoon detected 3 local asymptomatic infections.
According to the Dalian report, on July 17, the three infected people flew from Dalian to Zhangjiajie, and on the way to Nanjing Lukou Airport, they stayed for about 2 hours. On July 22, they watched the performance at Zhangjiajie Charming Xiangxi Theater. .
On July 27, Dalian added one more locally confirmed case. There is no history of living in Nanjing Lukou Airport. However, on the evening of July 22, he watched the performance at Zhangjiajie Charming Xiangxi Theater with the above three asymptomatic infections. Adjacent row.
On July 28, Chengdu notified 5 new local confirmed cases and 1 local asymptomatic infection. Among them, 5 had been to Zhangjiajie and 1 was an associated case.
On July 29, Jiangsu Huai'an notified that 4 tourists who went to Zhangjiajie had tested positive for nucleic acid, and 3 of them were employees of an enterprise in Hongze District.
Prior to this, the company had organized 67 employees including the above three people to travel to Zhangjiajie.
The performance of the charming Xiangxi Theater is a key point in the spread of the epidemic. Various localities have issued emergency prompts to find relevant personnel and carry out investigations.
On July 28, the Zhangjiajie New Crown Pneumonia Epidemic Prevention and Control Work Headquarters Office issued a notice stating that all the audience of the first charming Xiangxi Theater performance on the evening of July 22 belonged to high-risk groups.
The number of newly diagnosed local cases in Nanjing is also increasing.
From 0:00 to 24:00 on July 28, 18 newly diagnosed cases of local new coronary pneumonia in Nanjing.
From July 20 to the afternoon of July 29, Nanjing City reported a total of 171 local confirmed cases and 2 local asymptomatic infections.
At present, Nanjing City is carrying out the third round of nucleic acid testing for all employees in different areas and time periods.
According to incomplete statistics, the infected and close contacts involved more than 200 people in 7 provinces and 10 cities.
The epidemic has exposed loopholes in the prevention and control of key places such as airports and scenic spots. The frequent flow of people during peak tourist seasons has further increased the risk of spread
The epidemic was imported from abroad and spread within the country, showing the characteristics of hidden spreading and wide spreading.
The beginning of the spread chain is the airport.
On July 20, the New Coronary Pneumonia Epidemic Prevention and Control Headquarters in Jiangning District, Nanjing City received a report from the Lukou Airport Epidemic Prevention Team. Among the regular nucleic acid test samples of Lukou Airport staff, 9 cases tested positive.
Subsequently, the number of personnel infections continued to rise.
The first infected person was the passenger plane cleaning staff, and then the cleaning staff, airport staff and related personnel gradually became ill. The infected people were also found among the passengers entering and leaving Lukou Airport.
On July 27, Nanjing notified that it was the Delta mutant strain that caused the epidemic, which means that the virus was imported from abroad.
According to Xinhua News Agency, it is currently highly suspected that during the disinfection and cleaning process after the arrival of international flights, airport cleaning staff did not protect themselves and caused infection, which then caused a cluster of transmission among cleaning staff, and then spread to other airports through cleaning staff. For personnel and passengers, the initial infection time should be around July 10.
Border ports, international airports, stations, etc. function as hubs, and the risk of virus import is high, and they are the top priority of epidemic prevention and control.
Although the transmission chain of the epidemic has not been fully investigated, the “breaking of the defense” at the airport is an obvious loophole.
Nanjing Lukou International Airport, as one of the country's main trunk airports, has a large throughput and strong mobility, which has accelerated the spillover of the epidemic.
In addition, Nanjing Lukou International Airport has problems such as lack of supervision and unprofessional management, and various measures for epidemic prevention and control have not been implemented in detail.
For example, the original separate operation of international flights and domestic flights was changed to a unified mixed operation. The prevention and control of first-line outsourcing personnel was not strict, and the cleaning personnel responsible for overseas and domestic were not distinguished; after the positive samples were found, Lukou Airport The prevention and control of relevant personnel is not in place, which has led to the spread of the epidemic.
Zhang Boli, an academician of the Chinese Academy of Engineering, previously analyzed that the epidemic indicated that the airport may have imprecise aspects of garbage disposal, airport cleaning, warehouse cleaning, etc., and more detailed investigations are needed to plug the loopholes.
Many Nanjing-associated cases travelled to many places with a large range of activities, which resulted in secondary transmission.
The emergence of multiple infected persons with a history of residence in Zhangjiajie has exposed loopholes in the prevention of epidemics in scenic spots and other densely populated places.
"There were about 2,000 spectators that night, and everyone was sitting next to each other without a separate seat." The staff of Zhangjiajie Charm Xiangxi's official customer service hotline said in an interview with the media that everyone is required to wear masks when entering the theater, but there is no guarantee. Tourists wear masks throughout the journey.
"Nowadays, many scenic spots have no current restrictions, and many people don't wear masks." Zhang Boli said that summer vacation is the peak tourist season, and masks must be worn. Scenic spots and airports need to be extra vigilant.
Zhang Wenhong, director of the Department of Infectious Diseases of Huashan Hospital affiliated to Fudan University and leader of the Shanghai New Coronary Pneumonia Medical Treatment Expert Group, said that the spread of the epidemic in Nanjing across provinces is a new mode of domestic transmission caused by imported epidemics.
At present, the cases in other provinces and cities are basically found in the screening of relevant key populations, and they are still on the transmission line related to Lukou Airport, which indicates that the epidemic is still under control.
In Nanjing, family clusters of people infected with Lukou Airport are the main feature.
Nanjing has already adopted strict prevention and control measures. If the control is effective, it can be controlled within a few weeks.
"The key is to follow up 1-2 weeks of surveillance. If there are more cases that are not directly related to Lukou Airport, it indicates that the scale of the epidemic will expand, and more decisive measures may need to be taken." Zhang Wenhong said.
Virus mutations have caused some people who have been vaccinated to be infected, but the prevention rate of vaccination can reach more than 90%, and there is still a protective effect.
In this epidemic, the role of vaccines has attracted attention.
According to the announcement, in the newly reported local confirmed cases of new coronary pneumonia in Chengdu, both adults received two injections of the new crown vaccine.
I have been vaccinated, why are you still infected?
Has the vaccine "failed"?
"The vaccine still has a protective effect." Bao Changjun, an expert from the Jiangsu Provincial Health Commission's New Coronary Pneumonia Prevention and Control Expert Group and director of the Jiangsu Provincial Center for Disease Control and Prevention, said in an interview that research has shown that among the confirmed cases, people who have not been vaccinated have transferred. The rate of severe illness or occurrence of severe illness is significantly higher than that of people who have been vaccinated.
Compared with unvaccinated cases, the time from diagnosis to antibody production in vaccinated cases is shorter, the CT value is higher (low virus concentration), and the hospital stay is shorter.
Professor Liang Zongan, director of the Department of Respiratory and Critical Care Medicine of West China Hospital of Sichuan University and executive deputy head of the Sichuan New Coronary Pneumonia Medical Treatment Expert Group, introduced that although the delta mutant strain that caused this round of epidemic is highly infectious and prone to severe illness, According to domestic and foreign data, vaccination can effectively prevent severe illness and reduce deaths.
At present, most of the deaths caused by the new coronavirus are people who have not been vaccinated.
Judging from the situation of recent local cases, the overall condition of the confirmed cases is stable, mainly mild and common, which verifies the protective effect of the vaccine, which is consistent with the expert's previous prediction.
In fact, no vaccine can achieve 100% efficiency.
The protective effect of the vaccine is mainly reflected in protecting the human body from being infected by the virus as much as possible, even if it is infected with the virus, it will not cause severe illness and death.
"Vaccination does not mean that there will be no infection." Ding Yuan, deputy director of the Shanghai Health Promotion Center, emphasized that this is like getting a flu vaccine in winter does not mean that you will not be able to get flu. Individuals must implement protective measures. Under the "double protection", it can reduce The probability of getting the flu may reduce symptoms.
In addition, experts reminded that after the full vaccination, it usually takes 2 weeks to get sufficient immunity.
If you are exposed to the new coronavirus before the maximum protection of the vaccine has been reached, you may also be infected, so you must protect yourself after being vaccinated.
How effective is China's vaccine?
Researchers have carried out a phase III clinical trial of the new crown inactivated vaccine "Kierlai Fu" developed by Beijing Kexing Zhongwei Biotechnology Co., Ltd. in Turkey.
Recently, the British medical journal "The Lancet" published the interim analysis results of this trial online, showing that 14 days after the two doses of vaccines, the effective rate of preventing symptomatic infections was 83.5%, and the effective rate of preventing new crown-related hospitalizations 100%.
In May of this year, the international medical journal "Journal of the American Medical Association" published "Evaluation of the Protective Efficacy of Two Novel Coronavirus Inactivated Vaccines Against Adult COVID-19 Infection" published by Sinopharm Sino Biotech.
The results of the study showed that the two new inactivated vaccines of China Biologics can produce high-titer antibodies and form effective protection 14 days after two injections, and the positive conversion rate of neutralizing antibodies in the whole population has reached more than 99%.
Among them, the protective efficacy of two new crown inactivated vaccines, Beijing Institute of Biological Products (BIBP) and Wuhan Institute of Biological Products (WIBP), which are affiliated to China Biological Sciences, are 78.1% and 72.8%, respectively.
“Due to the mutation of the virus, there have been some cases of infection after vaccination, but based on previous experience, the prevention rate of vaccination can reach more than 90%. We should continue to actively promote vaccination.” Zhang Boli said.
The domestic sporadic and locally clustered epidemics are intertwined and superimposed. The risk of epidemic transmission may exist anytime and anywhere, and prevention and control cannot be relaxed for a moment.
At present, the delta mutant strain has become the "protagonist" of the new crown pneumonia epidemic in many countries.
The previous outbreaks in Guangdong and Ruili in Yunnan were confirmed to be caused by the Delta strain.
According to a report released by the WHO, from July 19 to 25, more than 3.8 million new cases of new coronary pneumonia were reported globally, an increase of 8% compared to the previous week.
According to Japanese media reports, on July 28, the chairman of the Japan Medical Management Research Institute, Masahiro Shang said that due to the spread of the delta mutant strain, the country’s new crown infection cases from the end of July to the beginning of August will "double" compared to the same period last year.
Tian Yihiro, professor of infectious disease at Toho University in Japan, said that the number of infections in Tokyo "will not decline for the time being, but will continue to increase, and the medical tension will continue."
The delta mutant strain is also the main mutant virus circulating in the United States, accounting for 83.2% of the newly confirmed cases in the United States.
According to the New York Times, as of July 26, the average number of new confirmed cases in the United States in the past week has increased by 144% compared with two weeks ago; the average number of new deaths has increased by 7% compared with two weeks ago.
The US Centers for Disease Control and Prevention (CDC) stated that the recent severe rebound in epidemic indicators has a lot to do with the accelerated spread of the Delta strain.
In response to the menacing Delta strain, the CDC recommends that people who have been vaccinated also wear masks in indoor public places in the United States. This changed the agency's decision two months ago.
On May 13 this year, the CDC said: “Persons who are fully vaccinated against the new crown do not need to wear a mask or maintain social distancing during indoor and outdoor activities.”
The new crown virus continues to mutate, what will happen in the future?
In January this year, "Nature" magazine sent a questionnaire to 119 immunologists, infectious disease experts and virologists to investigate their views on the new coronavirus.
Among them, nearly 90% of scientists believe that the new coronavirus will not disappear completely, but will turn from a pandemic to a local epidemic.
However, with vaccination or herd immunity after infection, the harm caused by the new coronavirus is expected to gradually decrease and eventually be controlled within an acceptable range.
"The Nanjing epidemic has made us see the ubiquity of the virus again. Whether we like it or not, there will always be risks in the future." Zhang Wenhong wrote on Weibo.
The epidemic is not over yet, and we are still looking for a long-term solution to the new coronavirus.
Domestic sporadic and locally clustered epidemics are intertwined and superimposed. The risk of epidemic spread may exist anytime and anywhere, and prevention and control cannot be relaxed for a moment.
The results of epidemic prevention are hard-won and need to be maintained by everyone.
Even if the weather is hot, you must adhere to scientific standards to wear masks; even if you are vaccinated, you should also take personal protection and never take it lightly.