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Zhong Nanshan said that the new corona virus has “environmental transmission”, and some experts said that isolating the live virus from the outer packaging indicates that there is a risk of “material transmission”.
The new crown prevention and control faces new “environmental transmission” problems
On December 1, law enforcement officers from the Dongcheng District Market Supervision Office scanned the mini-program “Beijing Cold Chain” for frozen food in a supermarket. Profile Photo / Photo by Wu Ning, Beijing reporter News
Recently, there have been sporadic epidemics in many places in China. In addition to reporting new cases, many imported foods from the cold chain or outside packaging surfaces have also tested positive. Yesterday, Zhong Nanshan raised the issue of the “environmental transmission” of the new corona virus in public. What does “environmental transmission” mean? How should we prevent and control it now? The Beijing News connected with experts in the field of epidemic prevention and control in China who are involved in front-line prevention and control to explain this.
Follow-up 1
What does “environmental transmission” refer to?
Jiang Rongmeng, director of the Office of the National Center for Quality Control of Infectious Diseases, said that “environmental transmission” is not a new form of transmission of the novel coronavirus, but essentially a “material transmission.” As long as an infected person contaminates the environment and surrounding objects, healthy people can become infected after contact.
Luan Rongsheng, chairman of the Epidemiology Branch of the Sichuan Preventive Medicine Association and professor of epidemiology, said that in the past respiratory diseases have existed both person-to-person and person-to-person, and person-to-person transmission it is the most important mode of transmission. Healthy people have close face-to-face contact with patients and inhale droplets, thus infecting the virus.
The risk of “material transmission” is relatively small. The transmission route is that the patient discharges droplets and excrements with live virus, which contaminate the environment and surrounding objects, after a healthy person touches the virus on these objects, touches the mouth, nose and eyes, infecting .
The journalist learned that the Chinese scientific research team confirmed that the new corona can be transmitted by aerosols and discovered the new corona virus in the air of toilets that patients have used. Compared to large droplets, aerosols are smaller in volume, easy to float and stay in space, and they spread more widely. Luan Rongsheng said that aerosol transmission is often generated in relatively closed special spaces, such as hospitals, and is not the main route for the spread of new crowns in open public places.
Follow-up 2
What is the impact of “environmental transmission” on the prevention and control situation?
Jiang Rongmeng analyzed that the reason for highlighting the problem of “environmental transmission” is that there have been many sporadic cases in the country recently, and the traceability of the origin of the infection has not been entirely clear, so they have been considered the risks that the environment brings. Furthermore, the spread of the epidemic around the world has also put pressure on the prevention and control of the epidemic in China.
Luan Rongsheng introduced that the “environmental transmission” that has been the focus of prevention and control of infectious diseases in the past has been mainly short-range. For example, after a case occurs in a certain area, the surrounding environment that the case has been in contact with, such as residence, hospital ward, etc. The reporter learned from Beijing CDC staff that after new cases are discovered, nucleic acid testing and subsequent removal from their living environment will be carried out. At the moment, what stands out the most is the remote transmission.
“The quantity of imported items is too large and there are many types. Monitoring and disinfection are difficult to cover. It is more problematic to prevent and control.” Jiang Rongmeng said that China’s current epidemic situation is relatively stable and there is no large-scale local epidemic situation. The spread of the new crown within the country has basically been blocked. . However, the epidemic is still prevalent throughout the world. Due to the large population of infected people, many people have given up nucleic acid testing and continue to move and work in society. Imported products are also contaminated by infected people. Autumn and winter are the seasons of high incidence of respiratory diseases, which facilitates the spread of the new crown.
In the context of frequent world trade and economy, the exchange of people and goods continues. Personnel control is relatively clear and objects move across the ocean. The virus can survive in the cold chain environment and reach the country. When domestic workers are exposed to the surface virus, they can become infected.
Luan Rongsheng introduced that China’s previous research on isolating live viruses from outer packaging has shown that there is a risk of “material-to-human transmission” of the new crown. In addition, China has a long border and the prevention and control of the import of land is relatively difficult, and the prevention and control face new problems.
“It’s not that the risk of ‘environmental transmission’ is very high. In fact, the probability of positive detection on the outer packaging of imported food from the cold chain is very low. However, it is relatively easy to prevent people , and it’s relatively difficult to prevent things, “Luan Rongsheng said. Judging by the current cases in the country, transmissions related to imported goods mainly occur in specific occupations such as cold chain workers and are not caused by ordinary citizens after the goods enter the market.
Follow-up 3
How to face the new challenge of “environmental transmission”?
Luan Rongsheng believes that in order to address “environmental transmission”, we must first start with the border quarantine. When imported products from the cold chain enter the country, the Customs and Markets Supervision Office will act as the competent authority to control, quarantine and disinfect. For imported cold chain products that have been found positive many times, there must be a fusion mechanism and they are no longer imported.
The journalist learned that since October, China has issued regulations on the prevention and control of the cold chain on many occasions.
In the “Notice on further improvement of the management of traceability of food in the cold chain”, it is proposed to establish and improve a system of management of traceability of food in the cold chain consisting of a national platform , a provincial platform and an enterprise platform, so that key cold chain food can be imported from customs After inspection, information traceability of the entire chain of storage and distribution, production and processing, wholesale and retailers, and catering services.
The “Notice on the printing and distribution of the work plan for the preventive and complete disinfection of imported food from the cold chain” stated that the customs department should be responsible for carrying out the monitoring and testing of the new food coronavirus imported from the cold chain in accordance with regulations, and organize and guide imported food importers from the cold chain and customs inspection sites. Preventive and comprehensive disinfection treatment of the inner walls of imported cold chain food containers and the outer packaging of selected goods at the port link.
He also mentioned that vaccines are an effective means of fighting the epidemic. With the launch of the new corona vaccine in the United States and the United Kingdom, subsequent reports of adverse reactions have caused public concern about safety. He said that most adverse reactions are mild and transient. In relatively severe cases, it is not enough. It is determined that there is a direct relationship with the vaccine, and its incidence is similar to that of the normal population, and may occur without vaccines. Once the vaccine becomes popular and the immune barrier is established, the risk of spreading the epidemic will be greatly reduced.
Jiang Rongmeng believes that ordinary citizens need not be overly anxious. Viruses are part of the natural world, and humans have lived with viruses for a long time. In the face of the new crown, it is important to protect high-risk groups such as the elderly and patients with underlying diseases. Existing self-protection methods, such as wearing masks, hand hygiene, frequent hand washing, and reducing gatherings, can achieve good results at low cost.
Beijing News reporter Dai Xuan
