Recently, the local epidemic caused by Han, a 22-year-old female student who returned to Harbin from the United States, has spread to 37 people (including asymptomatic infected people 15). However, after returning to China, Han, a foreign student, tested negative for nucleic acid twice, which lifted the isolation at home, but it may have been transmitted to Cao, a stranger upstairs. The CDC believes that Cao may be exposed to the polluted environment (such as elevators) in Korea.
Coincidentally, an imported case reported by Beijing Center for Disease Control and Prevention on April 16, an American student who went to Beijing for isolation 14 days, was negative after three tests, and was diagnosed five days after being released from isolation, infecting three family members. The international student lived alone in a room while he was at home.
Experts said that there are still many unknown factors in COVID-19 that we need to explore and understand constantly, and it is suggested that those who have expired in isolation should not be taken lightly after returning home.
Harbin: The test was negative. After the home isolation was lifted, the neighbor was diagnosed with infection.
Let's take a look at how the local epidemic in Harbin spread.
Harbin Municipal Health and Health Commission informed that Han, female, aged 22, arrived in Harbin from the United States on March 19, 2009, and was transported to her home at around 22: 00 that night (closed-loop management from the airport to the gate of the community) by "special delivery", and was observed in isolation at home according to regulations. During the period, Korean 3 1 nucleic acid was negative, and IgM and IgG antibodies were negative. On April 3, Han met the isolation conditions 14 days, and the nucleic acid test was negative again, and the home isolation was lifted.
On April 9, after Guo Moming, a citizen of Harbin, was diagnosed with illness, it was found through investigation that Cao, a close contact of Guo, lived in Fuli Jiangwan Community, Daoli District, Harbin, and lived in the same building and unit as Han, and they were neighbors upstairs and downstairs. They didn't know each other. During the isolation, Han didn't go out at home. Therefore, on April 10 and April 1 1 day, COVID-19 was diagnosed as a former infected person (imported from abroad).
After investigation, the unit where Cao and Han live is an elevator, and the whole unit * * * uses an elevator, so there is a space that may be polluted; Because of the building structure and other reasons, there is also the possibility of virus transmission between the upper and lower adjacent floors, and the two have the conditions for infection. Cao was diagnosed with illness. At present, the investigation on the infection between Han and Cao continues.
Then this wave of local epidemic started from Cao, and 37 cases (including 15 asymptomatic infected persons) were reported one after another, all of which were related.
Beijing: I returned to Yang after lifting the isolation at home, infecting three family members.
Let's take a look at the spread of this case in Beijing.
On April 16, the Beijing Center for Disease Control and Prevention informed that a China student studying in Miami, USA, was isolated after returning to Beijing from the United States on March 24th, and all three nucleic acid tests were negative. On April 8th, after the quarantine expires 14 days, the quarantine will be lifted. On the third day after returning home, I had a fever and expectoration on April 10. I went to the hospital on April 13, and my nucleic acid test was positive! As soon as the family checked, their mother, brother and grandfather were all diagnosed. A family of five, * * * four confirmed! The foreign student lived alone in a room and didn't go out when he was at home.
By comparing the spread of these two cases, there are two characteristics worthy of attention:
First, they are all related cases imported from abroad. After two or three nucleic acid tests, all the foreign students were negative before the isolation 14 days. The difference is that Han in Harbin, after lifting the home isolation, did not test positive twice, but there may be virus transmission, and neighbor Cao was infected and sick. After the international students in Beijing were released from centralized isolation, they went home and immediately returned to Yang. Soon, three family members reported that they were infected and diagnosed.
Second, there is the possibility of environmental infection. Han and his neighbor Cao, strangers, may just get sick because of contact with the environment (such as elevators) polluted by Han. This international student in Beijing lives in a room alone and doesn't go out during his stay at home. After he returned to Yang, three family members fell ill one after another.
Walking the same stairs as people who returned to Beijing from abroad, they were diagnosed with infection.
Environmental infection is not a case.
This infection was also found in the first imported case in Beijing.
According to the Beijing CDC, Liu, who lives in Dahezhuang Hospital, No.3 Suzhou Street, Haidian District, developed symptoms such as fatigue and fever on March 10, and his body temperature returned to normal after taking the medicine. On March 14, I went to the fever clinic of Haidian Hospital to take medicine and go home for treatment. On March/0/7, Kloc had a fever again and took Tylenol and cough medicine. On the evening of March 20th, I went to the fever clinic of Haidian Hospital again, and novel coronavirus tested positive for nucleic acid. After a comprehensive CT image, blood test and antibody detection, it was diagnosed as a confirmed case on March 23 and sent to a designated hospital for treatment.
How was Liu infected?
Liu's downstairs neighbor, Li, arrived in Beijing from Britain on March 5 and was isolated at home for observation. During this period, there are activities in the community and shopping activities in Yonghui Supermarket. On March 7, I took the stairs to the community to apply for a pass, and I became ill on March 9. March 1 1, take the stairs and walk to Haidian Hospital for treatment. On March 12, he was diagnosed as a confirmed case in COVID-19.
Epidemiological investigation found that both Liu and Li had stair behaviors recently, and Liu may have been exposed to the stair environment polluted by Li before March 1 1.
On the afternoon of April 16, Beijing held a press conference on novel coronavirus epidemic prevention and control.
Beijing Municipal Health and Health Commission reminded
Very few infected people have a long incubation period, which brings new challenges to the prevention and control work.
Xu Hejian, deputy director of the Propaganda Department of Beijing Municipal Committee and director of the Municipal Government Information Office, said at the press conference of 16 that the confirmed cases imported from abroad were diagnosed two days after the quarantine was lifted on 14, and five days later, which also caused family cluster infection. "This warns us that COVID-19 virus is a newly discovered virus, and there are still unknown factors for us to explore in epidemic prevention and control."
In the bulletin of Beijing Health and Health Commission, it is emphasized that some infected people have other symptoms for a long time, which may cover up similar symptoms in COVID-19. Very few infected people have long incubation period, positive nucleic acid test, late onset time and atypical early symptoms, which brings new challenges to prevention and control work.
Remind citizens and friends that after the expiration of the quarantine period, people should not take it lightly and need to continue to live alone and reduce contact with their families; Keep the environment clean in daily home life, open the window frequently in the bedroom, and do not use towels, cups and tableware among family members. When the environment and articles are polluted, they should be cleaned and disinfected, hand hygiene should be maintained at all times, and a safe social distance should be maintained.
Zhong Nanshan once said that the characteristics of COVID-19 virus are: high transmission power, higher than SARS, MERS and influenza.