Original title: 2022 epidemic prevention concerns| how risky is the "material transmission" of the new crown virus? How to prevent it?
At the press conference on epidemic prevention and control held by Beijing Municipality and Shenzhen City and Zhuhai City in Guangdong Province on January 17, they each reported the situation of local confirmed cases, and all of them judged that the possibility of contracting the virus through overseas items was not ruled out.
Why did you make this judgment? How risky is the coronavirus being "passed on in kind" through foreign mail and other items? How can individuals be better protected? The reporter relied on authoritative information sources to sort out and summarize.
Why doubt "material transmission"? Nucleic acid detection and gene sequencing give directions
Pang Xinghuo, deputy director of the Beijing Municipal Center for Disease Control and Prevention, reported at the press conference on the 17th that a locally confirmed case previously found in Beijing had no history of living in other provinces and cities in the 14 days before the onset of the disease, and after epidemiological investigation and big data comparison, it was not found that it coincided with the trajectory of inbound personnel, people from risk areas outside Beijing, cases and close contacts.
According to reports, the case reported that he had recently sent and received international mail. After sampling and nucleic acid testing, the cdcover personnel found that some of the outer surfaces of the packages, the inner surfaces and the paper specimens in the documents showed positive. Genetic sequence analysis of the case specimens showed that the virus was different from previous cases in Beijing and recently reported strains in China, did not belong to the same chain of transmission, and were similar to some strains isolated in North America and Singapore in December 2021.
Pang Xinghuo said that combined with the epidemiological history of the case, the detection results of the suspicious item sample and the genetic sequencing results of the case specimen, the possibility of infecting the virus through overseas items is not ruled out.
On the same day, Shenzhen held a press conference to inform that the viral genome of a local local case was also different from the previous imported cases, and was 100% homologous with the genome uploaded in North America in the global database.
Lin Hancheng, a second-level inspector of the Shenzhen Municipal Health Commission, said that the case was engaged in the collection and delivery of overseas frozen reagents, had contacted and spun off express deliveries from North America, did not do personal protection, and did not rule out the possibility of being caused by the import of new coronavirus pollutants from abroad. Combined with epidemiological investigations, the traceability of the virus is ongoing.
In addition, Zhuhai informed that according to the current on-site epidemiological investigation and laboratory testing, experts have judged that the local epidemic is not ruled out by exposure to contaminated inbound items, and further traceability is still being stepped up.
On January 13, in the Jingdong "Asia One" park in the Xi'an International Port District, the staff sorted the couriers. Photo by Xinhua News Agency reporter Liu Xiao
How risky is "material-to-human"? Not the main mode of transmission of the new crown virus
On January 16, the Department of Safety Supervision and Administration of the State Post Bureau issued a notice requiring enterprises to do a good job in disinfection and ventilation of international mail express processing sites, and for imported international mail express mail, after entering the production and processing link, the first time to carry out full coverage of all aspects of the outer packaging, and formulate a high-risk epidemic prevention and control plan for imported mail express mail from high-risk countries and regions.
Cases of the new crown virus surviving for a long time in low temperatures and spreading through the cold chain have been reported in parts of the mainland in the past year or so. The prevention and control of the epidemic in the mainland has always insisted on the prevention of people, things and the environment.
However, combing through the situation of "material transmission to people" in public reports, it can be found that it is basically a personnel infection at the first contact point such as market and logistics. One of the important reasons is that there are more restrictions on "material transmission to people", which is not the main way of transmission of the new crown virus.
At the press conference of the joint prevention and control mechanism of the State Council held earlier, Wu Zunyou, chief expert of epidemiology of the Chinese Center for Disease Control and Prevention, introduced that to cause infection by "material transmission to people", three conditions need to be met: first, the pollution of the goods is heavier; second, the virus survives on the surface of the object for a long time, generally speaking, the lower the temperature, the longer the virus survives; the third is that appropriate protective measures are not taken when contacting contaminant products.
Wu Zunyou believes that compared with human infection, the amount of virus infected by the substance is different, and the case is prone to asymptomatic infection or mild infection, which is often found in a timely manner and may trigger a new epidemic.
In previous cases, some food surfaces tested positive for nucleic acid, which once caused concerns about "material-to-human transmission". To this end, the relevant person in charge of the National Food Safety Risk Assessment Center specifically said at the press conference of the joint prevention and control mechanism of the State Council that live viruses, dead viruses, and fragments of viruses may be positive for nucleic acid. Just being positive for nucleic acid does not mean that it is contagious, but only that it has been contaminated by the new crown virus.
On November 20, 2021, in the Huibo Jiayuan Community on Xueyuan Road Street in Haidian District, Beijing, the staff prepared to put express items into the express locker. Photo by Xinhua News Agency reporter Ren Chao
How can individuals protect themselves? Minimize direct contact with overseas couriers
Disease control experts suggest that when receiving express delivery, especially overseas express delivery, protective measures such as wearing masks, properly disposing of outer packaging, and disinfecting internal parts can effectively reduce the potential risk of being infected by the new crown virus.
Zhang Liubo, chief expert of sterilization at the Chinese Center for Disease Control and Prevention, said that it is best to choose a contactless method for receiving express delivery, or wear masks and gloves as much as possible. After removing the outer packaging, remove the gloves in time and clean your hands to do a good job of hand hygiene.
Pang Xinghuo suggested that when receiving mail or items from abroad, wear masks and disposable gloves correctly to reduce direct contact and communication. Pick up the parts at fixed locations as much as possible for contactless handovers.
In addition, when disassembling the parts, try to carry out outdoors, the outer packaging does not have to be taken home, can be classified according to the domestic garbage; if it is taken home, the inner and outer packaging can be fully disinfected with chlorine disinfectant or 75% alcohol. After handling the mail, take off the gloves in time, change the mask, carefully disinfect the hands or wash the hands, and avoid touching the mouth, eyes, and nose with unclean hands.
Reporters: Dong Ruifeng, Song Chen, Wu Wenxu, Wang Haoming
Editor: Nie Yan