(Fighting New Coronary Pneumonia) Three questions about the cold chain traceability of the new coronavirus: why?

Where is the difficulty?

How to do it?

  China News Agency, Beijing, August 30 (Reporter Li Chun) In a recent interview with China News Agency and other media in Beijing, Liu Liu, assistant to the director of the Institute for Viral Disease Control and Prevention (Institute of Viral Diseases) of the Chinese Center for Disease Control and Prevention, and deputy director of the National Influenza Center Jun pointed out that the low positive detection rate of cold chain products does not mean that the possibility of virus introduction is low. Considering the large number of imported cold chain products, even if the proportion of contaminating viruses is low, the risk of infection or imported epidemics is still not acceptable. Ignore.

  The China-World Health Organization New Coronavirus Traceability Joint Research Report pointed out that the cold chain is a "possible" way to introduce the new coronavirus, and it is recommended to make it an important part of the next traceability work.

Why is the introduction of cold chain a focus of traceability work?

What difficulties are currently facing cold chain traceability?

How should the global cold chain traceability research be conducted?

Data map: The staff collected nucleic acid samples of imported cold chain food on site.

Photo by China News Agency reporter Chen Guanyan

Why is the introduction of cold chain one of the key points of global traceability?

  The new crown epidemic that began in Beijing Xinfadi in June 2020 has caused people to pay attention to the possibility of cold chain introduction of the epidemic, and then China has repeatedly detected the new crown virus nucleic acid in imported cold chain or its outer packaging samples.

Until the new crown epidemic in Qingdao last October, scientists from the Institute of Virology of the China Centers for Disease Control and Prevention isolated live viruses on the outer packaging of imported cold chain foods, which directly proved that the new crown virus can be spread over long distances through the cold chain.

  Liu Jun introduced that during the joint traceability study conducted by Chinese and foreign experts in Wuhan, they analyzed the correlation between confirmed cases in the South China Seafood Market and cold chain transmission, and found that stalls related to cold chain goods had a significantly higher proportion of confirmed cases than none. Booth of cold chain products.

The test of environmental samples in this market also found that of the 21 stalls with positive samples, 16 were selling cold chain products.

  In addition, the joint expert team conducted research on the environmental viability of the new coronavirus at different temperatures, and combed through the evidence of cold chain correlation of multiple rounds of imported epidemics that occurred in mainland China after the Wuhan epidemic, and found that the new coronavirus can survive the cold The outer packaging of the chain product survives.

  "The relevant data and evidence of these preliminary work all prove that the new crown virus can be spread over long distances through the trade of cold chain products." Liu Jun pointed out that although the current positive detection rate of the new crown virus for cold chain products is not high, it is not It means that the possibility of virus introduction is low.

Even if a large number of imported cold chain goods are contaminated by the virus, the risk of causing imported epidemics cannot be ignored, or it may become an "incidental necessity".

Where is the source of cold chain propagation difficult?

  "The cold chain is an important carrier for the long-distance transmission of the virus across regions, countries, and even across continents." Ma Huilai, director of the China Field Epidemiology Training Program of the China Centers for Disease Control and Prevention, said that cold chain transmission is through contact with virus contamination. The process of passing from person to person caused by cold chain items and their packaging is more secretive, and the transmission cycle may be longer.

  She pointed out that based on its characteristics, cold chain transmission has brought huge challenges to epidemic prevention and control.

As far as China is concerned, in addition to strengthening the prevention and control of the epidemic situation for immigrants, "foreign defense import" should also increase the measures to prevent people and objects from cold chain or low-temperature environment, and extend the contact with these cold chain items. By.

  In addition, cold chain propagation also increases the difficulty of traceability, which requires certain technologies and prerequisites.

China has achieved good control over the local epidemics, and traceability investigations are conducted for each local epidemic, not only to trace the source of the epidemic, but also to find out where the epidemic prevention and control measures are not in place, and to fill in the prevention and control loopholes in a timely manner.

  Ma Huilai also stated that the development of cold chain traceability requires coordination of multiple departments.

For epidemics in China, traceability investigations must be conducted under the leadership of the national, provincial and local joint prevention and control mechanisms, and closely coordinated and jointly conducted by multiple departments.

In the global context, cold chain traceability investigations also require a global coordination mechanism.

  Xu Wenbo, director of the Institute of Viral Diseases of the Chinese Center for Disease Control and Prevention, also said that the new coronavirus can survive for a long time in a frozen environment, causing silent transmission.

The cold chain trade is a huge global physical trade, and fishing, processing, transportation and other links must rely on cold chain technology.

If a person infected with the new coronavirus participates in this process, the virus discharged by the infected person will contaminate the cold chain products and cause the new coronavirus to spread over long distances with the cold chain products.

"The cold chain traceability is still very difficult, and there must be a global cooperation mechanism."

Data map: Consumers use their mobile phones to scan codes to learn about cold chain food related quarantine information.

Photo by China News Agency reporter Li Siyuan

How should the global cold chain traceability work be carried out?

  Talking about how to carry out cold chain transmission and traceability work, the disease control experts interviewed said that this global problem needs to be solved through cooperation under the global framework and through the joint participation of global scientists.

  In Liu Jun's view, it is necessary to establish a scientific monitoring system for the cold chain transmission of the new coronavirus that can be extended to the world, and formulate a normalized international monitoring standard for cold chain transmission.

This is of great significance for cold chain tracing and further blocking the global spread of new crowns, including the spread of virus variants and the prevention and control of other infectious diseases with similar epidemic characteristics.

  "Further research on the scientific evidence that the virus spreads across borders and long distances through the cold chain, through international cooperation, is a very meaningful work." Liu Jun also hopes to establish a retrospective cold chain transmission through the above measures. International cooperation mechanism.

When a country finds a positive sample related to the cold chain, it can carry out traceability research in cooperation with the country of origin of imported products under the leadership of the WHO, based on scientific attitudes and the purpose of epidemic prevention and control.

  He also pointed out that it is recommended to cooperate with the source countries of imported cold chain related products in the South China Seafood Market in 2019 through international cooperation, and conduct traceability research on cold chain practitioners such as flow adjustment and testing.

  Xu Wenbo believes that the retrospective and retrospective detection of imported cold chain products for the new coronavirus is a complex project.

There are many types and large quantities of cold chain products imported by China. Which countries or enterprises and which batches of goods should be tested?

How to conduct scientific sampling and testing?

These are scientific problems that need to be solved urgently, and a scientific traceability plan needs to be carefully designed.