China News Service, Dalian, November 23 (Reporter Yang Yi) On November 23, Zhao Zuowei, director of the Dalian Municipal Health and Health Commission, notified at a press conference on the prevention and control of the epidemic in Dalian that the number of cases in this round of epidemic has rapidly risen to more than 300. , The clustering nature of the epidemic and the emergence of super spreaders have led to a rapid increase in the number of cases.

At least 3 cases each caused more than 30 direct follow-up cases, and the largest case was the case of Shao who was introduced into the university city, resulting in a total of 81 cases in the university city.

　　From 0:00 to 24:00 on November 22, 4 newly confirmed cases of local new coronary pneumonia in Dalian City.

Since November 4, Dalian City has reported a total of 339 local cases of new coronary pneumonia infection, including 301 confirmed cases and 38 local asymptomatic infections.

　　Zhao Zuowei pointed out that the number of cases in this round of the epidemic has rapidly risen to more than 300. The main reason is that this epidemic has been clustered through units, families, and schools, forming 4 main transmission chains, and rapid formation of the epidemic through multiple continuous transmission chains. The regions and groups gathered.

　　First, the case generation interval is relatively short.

In the transmission chain with relatively clear transmission relationship, the transmission has been passed down to 7 generations at most, and the average generation interval is about 2 days; the characteristics of epidemic clustering and the emergence of super spreaders have also led to a rapid increase in the number of cases.

　　Secondly, some cases showed intermittent detoxification and atypical clinical symptoms.

Before the case is diagnosed, the nucleic acid test results have repeated negative and positive results, and the parallel test results between laboratories are inconsistent.

From the outbreak of the epidemic to before the positive detection, 145 people who have undergone at least 5 nucleic acid tests or more are positive, accounting for 42.77% of the total number of cases. The maximum number of nucleic acid tests is one person before the positive is detected, a total of 16 nucleic acid tests during the quarantine period The test was negative.

　　In the cold storage of Keqiang's first station, closed-loop management personnel conduct inspection every other day, and non-closed-loop personnel conduct inspection once a week.

Haikuo Foods employees do double inspections a week.

Since the outbreak of the epidemic, the university city has been inspected once a day.

However, in all three cases, the test results on the first day were all overcast. More than a dozen cases were detected the next day, and the CT values ​​of many cases were lower than 20, and the CT values ​​of individual cases were about 10.

The speed of virus replication is extremely fast, and it grows exponentially within one day, the transmission power is greatly enhanced, and the law of transmission is difficult to grasp.

　　In addition, atypical early clinical symptoms are also a feature of this round of epidemics.

At present, only 5 cases have had early fever symptoms, and more than 50% of the cases have not had the typical symptoms of new coronary during the entire treatment process, and 157 cases have no significant changes in CT.

Except for 3 cases with early medical treatment experience, more than 98% of cases were detected through nucleic acid testing or even multiple rounds of nucleic acid testing.

At the time of detection, a certain scale of family gatherings had been formed.

　　The above characteristics led to the rapid spread of the epidemic, with more than 100 cases in a short period of time, and more than 300 cases in ten days.

At the same time, most of the cases detected in centralized medical observation sites recently have been isolated for more than ten days and have been positive, showing characteristics such as a long incubation period, which is likely to lead to the tailing phenomenon of the epidemic.

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