After genome sequencing, the transmission source of the "1-pass 80+" infection chain in Harbin has become clearer

• by EVOMT
• 2020-04-29

The source of the transmission chain of the closely watched rebound of the epidemic in Harbin finally surfaced. On the afternoon of February 28, Heilongjiang Province held a press conference to respond to the COVID-19, which reported the detection results of the transmission sources of the clustered epidemic rebound in Harbin. By publishing the results of the genetic sequencing analysis and research of the National Center for Disease Control and Prevention, it further proved that Han, a returned student, was very likely the source of this round of transmission chain< br/>  

Han infected more than 80 people in one person

According to previous relevant epidemic notifications, the source of the epidemic in Harbin was returned from the United States to Harbin on March 19th; Previous COVID-19 infected persons" Han. However, due to the fact that there is only Cao, a neighbor upstairs, and no other contacts, including his family, on the chain of direct infection, there are still some questions as to whether he is infectious and whether he is the source of this chain of infection

Academician Zhang Xue at the press conference

At the beginning of the press conference, Zhang Xue, an academician of the CAE Member, president of Harbin Medical University, and president of Heilongjiang Academy of Medical Sciences, said that on April 15, the Heilongjiang Provincial Center for Disease Control and Prevention sent two batches of samples to the China Center for Disease Control and Prevention for whole genome sequencing. Through the analysis of the whole genome sequence data of 21 people subsequently obtained, it was found that 18 people's genomes were identical, and the other three people were only 1 to 2 nucleotides apart, It has been determined as a transmission chain, proving that the virus was transmitted through a single person, and that the virus gene sequence originated from abroad. Therefore, existing research further supports Han as the source of transmission for this rebound in the Harbin epidemic

Zhang Xue: We are now analyzing the data of 21 genomes to determine a source and a source. Based on its genotype determination and evolutionary tree analysis, it is clear that the genome sequence of this virus is significantly different from that of the Chinese people, and it is imported from abroad. It can be said that it clearly supports that this is an imported case from abroad. Therefore, it is highly likely to be the source of this transmission chain

It is understood that after returning to Harbin, Han had undergone four nucleic acid tests between April 10 and April 15, and the results were all negative. Except for Cao, who was associated with the infection, Han had a dinner with his family and went to Shanghai for surgery after being released from quarantine, but no other infections were caused in the two places

Han has specific antibodies

For public requests; Why did Han, who had undergone surgery in Shanghai after being released from quarantine, only infect Cao, a neighbor he didn't know upstairs in Harbin, while other close contacts in the two places, including his family, were not infected; Academician Zhang Xue also explained the question

Zhang Xue: Her nucleic acid tests have been negative several times, but she has twice been positive for igg, which proves that specific antibodies have already been present. By that stage, the virus has been defeated in general terms. To say that she has no virus at all, I can't absolutely say that, but the possibility of infection through droplets, aerosols, and close contact has become very low, so from the perspective of immunology The knowledge and principles of infectious diseases are fully understandable

Heilongjiang implements the "" policy for all inbound personnel; 3 nucleic acid tests+1 serum antibody test&quot| Image from Heilongjiang Daily

The May Day holiday is not necessary and no travel is allowed

At the press conference, the Heilongjiang Provincial Center for Disease Control and Prevention also gave a reminder that the May Day holiday has encountered a period of epidemic prevention and control. Although the current domestic epidemic prevention and control has achieved significant phased results, Heilongjiang" External anti input, internal anti rebound" The pressure is still relatively high, so it is recommended that everyone not travel unnecessarily

Sun Wei, Deputy Director of Heilongjiang Provincial Center for Disease Control and Prevention, said: There are still risks in travel. It is recommended that we not neglect our carelessness, relax our safety precautions, try to go out as little as possible, do not gather, do not travel unnecessarily, and avoid cross city travel. In particular, it is recommended that citizens in Harbin, Mudanjiang, and other places should stay at home for holidays, reduce personnel flow, and reduce the risk of clustered epidemics

Take a trip to the nearby staggered peak and protect yourself on the way | Image from the official website of Heilongjiang Provincial Department of Culture and Tourism

How do I self-protect when traveling

" May Day" As the holiday approaches, some people hope to go out for short trips. Under the current situation of epidemic prevention and control in Heilongjiang, how do people travel? How to protect yourself? At the press conference, Sun Wei, Deputy Director of the Heilongjiang Provincial Center for Disease Control and Prevention, once again stated to "; City Code" Detailed introduction was made, and corresponding tips were given to those who hold the city code in terms of travel

Heilongjiang Province in Longjiang Health Code" Tricolor Code" Based on, the" City Code", That is, for newly diagnosed local cases, asymptomatic infections, and suspected cases in the community (excluding residents in closed building units), set" City Code"; Set up personnel for the entire building where close contacts reside" City Code"; Set the personnel range determined by the local headquarters based on the results of the flow survey" City Code&quot

Heilongjiang; May Day" Class A tourist attractions open for holidays are scheduled in different periods, and the number of tourists received should not exceed 30% of the approved maximum carrying capacity. The figure is from the official website of Heilongjiang Provincial Department of Culture and Tourism

Sun Wei emphasized that the setting is" City Code" "People are restricted to travel within the city, and there are no restrictions on their normal life and work, but they are restricted from leaving the city. If they need to go to other cities in the province due to special circumstances, they must be centrally isolated at the destination for 14 days and undergo two nucleic acid tests. Therefore, everyone is reminded to pay attention to their health code, understand the current prevention and control policies, and avoid being caught off guard due to not understanding the policies."

The First Affiliated Hospital of Harbin Medical University has set up a dedicated passageway for fever clinics and put respiratory clinics in front to prevent cross infection with other patients. | Image from the official website of the First Affiliated Hospital of Harbin Medical University