Influenced by Nanjing, 40 cases a day. Why do big cities break through defense again?

With the outbreak of COVID-19 abroad raging again, the virus once again tore a hole in China. 2 1 night, Nanjing announced the implementation of nucleic acid testing in the whole city, becoming another big city with a population of 10 million after Wuhan, Qingdao and Guangzhou.

In just two days, the Nanjing epidemic, which started at Lukou International Airport, quickly changed this city with a permanent population of nearly 10 million. First, on the morning of July 20th, the epidemic prevention and control headquarters of COVID-19, Jiangning District, Nanjing received a report from the special epidemic prevention class of Lukou International Airport, and some nucleic acid samples regularly detected by the staff of Lukou International Airport were positive.

At 6: 00pm, nine of the re-sampled test results were positive-eight were airport cleaners and 1 was cabin cleaners. That night, the relevant departments of Nanjing issued a notice, requiring passengers leaving Nanjing Lukou Airport to hold a negative certificate of 48-hour nucleic acid test from now on.

Also overnight, Nanjing launched a large-scale nucleic acid detection work in Jiangning and Lishui districts in order to quickly eliminate risks before the epidemic was controlled. But cunning viruses can always bring headache variables to epidemic prevention work through unexpected channels. On the morning of July 2 1, Nanjing Gulou Hospital issued a notice to suspend the outpatient service of Gulou Hospital. It is reported that the cessation of diagnosis is related to an asymptomatic infected person who went to Gulou Hospital for treatment. The official activity track shows that the patient accompanied his daughter to Gulou Hospital on the morning of July 20th.

Nanjing Gulou Hospital is a top-rated hospital in Nanjing, and it is also a key sensitive area for epidemic prevention. This incident not only adds a lot of risks and pressures to the follow-up epidemic prevention and epidemic situation adjustment, but also makes people worry. Before people realized it, how many important fortresses on the epidemic defense line had the virus secretly breached?

On the afternoon of July 2 1 day 13, the number of positive infections increased to 17, 9 cases were diagnosed and 8 cases were asymptomatic. So far, the source of this round of epidemic is still confusing and there is no definite answer. In addition, according to the official patient activity track, the earliest activity time can be traced back to July 6.

How long has this virus been quietly spreading in Nanjing? Is the "thunder" like Gulou Hospital just the tip of the iceberg? If the source and time of infection are not exact, does it mean that it is difficult to reconcile and trace the source? After careful consideration, these information blind spots in this round of epidemic in Nanjing are still worrying.

From coastal areas to inland areas, the virus is getting closer and closer. This is the third time that COVID-19 has successfully landed in a big city with a population of tens of millions in China in two months. It turns out that these cities have always been top students in China's anti-epidemic work. With the situation of overseas infection becoming more and more serious, many countries reopened their borders, and the virus landed in China from border cities to port cities and then inland cities.

Compared with the airports in Shanghai, Guangzhou and Shenzhen, where local epidemics have occurred in the past six months, Nanjing is far from the coast, with low airport throughput and fewer international flights to Hong Kong, so the risk of exposure to foreign viruses should be slightly lower. However, the virus still came. In June 5438+10, in the sporadic epidemic in Shanghai, Zhang Wenhong once introduced that this was a precise prevention and control of "catching mice in porcelain shops"; When the Guangzhou epidemic came, the government also hoped to use the method of "precise prevention and control", but it had to give up after two weeks, and everyone had a nucleic acid test.

In response to the Nanjing epidemic, after the news that COVID-19 was found to be positive for nucleic acid testing was announced, more than 10,000 residents in Lukou Street10 near Nanjing Lukou International Airport received nucleic acid testing overnight; Subsequently, the scope of nucleic acid detection was expanded to Jiangning District; Finally, on the evening of July 2 1, Nanjing announced the implementation of city-wide nucleic acid testing, becoming another big city to achieve "city-wide testing" after Wuhan, Qingdao and Guangzhou.

"All nucleic acids are rational choices, but the price is too high," an epidemiologist told Wen Jian at eight o'clock. Compared with last summer's silence, this summer's epidemic is almost one after another, and another wave of turmoil is almost normal.

It's been a year and a half since the epidemic and less than half a year since vaccination, but the situation is getting more and more serious. Chang Rongshan, a virologist at Shantou University, told Wen Jian at 8: 00: "The number of foreign infections has increased. It may have been only tens of millions at this time last year, but it may have expanded by more than ten times now. Moreover, the new strain has stronger spreading ability. New strains with stronger transmission ability are constantly exploring new ways to break through defense and find feasible ways to enter China.

Airport, a new breakthrough in COVID-19? COVID-19 has broken through the airport defense line, and Nanjing is not a special case. Under the background of virus mutation and accelerated spread, the airport has become a weak environment for epidemic prevention and control.

Taiwan Province Province, China, twice relaxed the quarantine requirements for unvaccinated entry pilots, from the original 15 days to 5 days, and finally changed to 3 days. At the end of March, 20021,British mutants entered the country by plane from airport hotel, Taoyuan, Huahang, Taiwan Province Province, causing a large-scale epidemic. In May, high flyers and Singapore broke through. After a cleaner was diagnosed, 25 staff members of Changi Airport were diagnosed within one week.

The mutant with enhanced transmission does bring difficulties to airport prevention and control. "It was not a loophole, but now it is." Associate Professor Zhang of the University of Pennsylvania made an image metaphor. "Like a net, the original virus has low transmission power and can only break through big loopholes, but now the virus can not only easily pass through big loopholes, but also break through small loopholes."

Shenzhen 6 14 epidemic, the first move is a customs officer, responsible for the flow adjustment of inbound passengers on international flights. Later, another restaurant waiter at the airport was detected, both of whom were infected with delta strain, which was highly homologous to the genome sequence of the positive case virus imported by CA868 international flight.

After this round of epidemic, Shenzhen upgraded the centralized management measures for high-risk workers, requiring hard isolation and comprehensive division of domestic and foreign flight sites to ensure that personnel trajectories do not cross; Centralized residence and "two points and one line" closed-loop management shall be implemented for high-risk personnel at international airports, land ports, ports and docks, customs, border inspection and other ports. Nucleic acid detection and isolation should be carried out for 14 days after leaving the post.

This time, the virus found another "defensive weakness"-airport cleaners. Chang Rongshan, a virologist at Shantou University, told Wen Jian at eight o'clock, "If there are undiscovered detoxifiers on the flight, their excreta and waste will be mixed in the garbage, which will be collected and cleaned by the cleaning staff, and the flight attendants will prevent and control them well and will not be easily infected; However, when collecting garbage and cleaning the computer room, if the prevention and control is not done well, it may be infected. "

In fact, the latest edition of the Technical Guide for Epidemic Prevention and Control of Transport Airlines gives reference suggestions for personal protection of all kinds of personnel. Among them, cleaners on international flights must wear disposable gloves, shoe covers and strip hats. In addition to N95 or KN95 masks, high-risk flights also recommend "wearing long clothes (or long sleeves) and trousers to prevent skin exposure, and it is recommended to use goggles/masks to recycle medical waste".

However, there are many obstacles in reality. Professor Zhang Yujiao from The University of Texas MD Anderson Cancer Center, USA, analyzed at eight o'clock that many untrained cleaners don't know how to protect themselves. Even if you know, it may be that the operation is not standardized. For example, Zhang said, "Just like protective clothing, you have strict requirements on how to wear it and how to take it off. If you undress differently, you may be infected. " .

According to the information released by official website of Nanjing Lukou International Airport, the vaccination rate of employees has exceeded 90%, which may have given the staff a sense of security, but neglected physical protection. Zhang explained, "The vaccine originally gave you some protection, but if the protection is not in place and it is completely exposed, the overall infection probability may rise instead of falling."

Cleaning workers with high risk of infection are actually not in the strict protection circle of the airport. After the virus was broken, it almost entered the market-the weekly airport screening gave the virus time to spread; The daily activities of cleaning workers provide space for the spread of the virus.

Many experts suggested that international airports need to increase the frequency and accuracy of nucleic acid detection, and at the same time strengthen the training and popularization of science for cleaning staff. The foreign epidemic continues to heat up, and the virus will continue to hit the airport defense line. The route of infection with low probability is becoming a reality one by one. This time, the loophole was filled. Where will it be next time?

Loophole, slack, strengthen the local epidemic in Nanjing, this is the fourth local epidemic in China in two months, followed by Guangzhou, Shenzhen and Ruili. It's been a year and a half since the epidemic, and we know more about the epidemic, and there are more and more ways to deal with the virus-universal nucleic acid testing, closed cities, and more than 65.438+04 billion doses of vaccination nationwide. In terms of epidemic prevention and control, China has almost exhausted all scientific and technological means and management means.

However, judging from the frequent local epidemics in recent months, this virus is smarter and faster than human beings, but the situation is getting more and more severe. Regarding the epidemic situation in Nanjing, an epidemiologist believes that "it has probably spread in the community, because the infection time has been one week, and the new virus has spread rapidly." But considering the seasonal factors, "the high temperature in summer is not conducive to the spread of this virus." It is still unlikely that the virus will spread further on a large scale.

"There must be loopholes in the prevention and control of overseas input at our airport, which is the warning that this epidemic has brought us." An epidemiologist who did not want to be named said: "Input management is sometimes hard to say as a loophole, because (limited by objective conditions), you can't be completely isolated like an infectious ward, you can't do that ... Now you are tired, and it will be normal to relax for a long time."

He suggested that the key population should be vaccinated with the third booster. He also mentioned that some researchers in China are already doing research on strengthening needles, but the relevant data have not yet been released. Tao Lina, a vaccine expert, believes that "there is no need to worry about strengthening the safety of immunization, but we can break through the same vaccine strengthening route of traditional vaccines and use other technical routes to strengthen vaccines. At present, there are adenovirus vector vaccines, and injection or inhalation may be considered. "

In fact, even if there is a booster, it is not without hidden concerns. After vaccination, many people will become mild or even asymptomatic infection, which is not easy to be found. "For our current' zero tolerance' prevention and control goal, this is almost unfavorable."