239 scientists from 32 countries jointly issued an open letter to the WHO, asking the WHO to pay attention to the evidence that the new coronavirus can be transmitted through the air. Benedetta Allegranzi, the head of the WHO's infectious disease prevention department, responded to this at the press conference that day and pointed out that WHO is open to "new evidence" about the spread of the new coronavirus through the air. .
Supported by the National Natural Science Foundation of China's New Crown Emergency Project (approval number: 22040101) and the National Science Foundation for Distinguished Young Scholars (approval number: 21725701), Peking University Yaosheng Research Group and Chaoyang District, Beijing The center has cooperated to make new progress in elaborating the mechanism of COVID-19 transmission. The research results are titled "COVID-19 patients in earlier stages exhaled millions of SARS-CoV-2 per hour". Published online on August 28, 2020 in the journal Clinical Infectious Diseases, link to the paper: https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1283/5898624 .
The cooperative team recruited nearly 60 COVID-19 patients (transported overseas and local cases in Beijing), 15 healthy people and some people without COVID-19 respiratory system infection, using the virus exhalation collection method proposed by the Peking University team (Nano Lett., 2012, 12. ,3722; has obtained a patent for invention), collected the Exhaled Breath Condensate of these people (pictured), and found that early new crown patients emit a large amount of new crown virus through breathing through RT-PCR (nucleic acid amplification) analysis test technology , Emitting up to several million per hour. The team's research found that the positive rate of new coronavirus in exhaled breath of patients with new crowns is as high as about 27% (total sample size n=52), and the positive rate of environmental related substance tables of patients with new crowns is 5.4% (total sample size n=242) ). In addition, the team also tested the new coronavirus in the air in the medical environment and the isolated hotel environment. The new coronavirus was also found in some samples, such as the air in the bathroom, with a maximum concentration of 6,000 viruses per cubic meter. It is worth pointing out that due to strict measures such as ventilation and disinfection, the concentration of the new coronavirus in the air is very low, which is lower than the minimum detection amount of RT-PCR, which can effectively block the transmission of the new coronavirus in the air.
This study confirmed for the first time that human respiration itself is a very important mode of transmission of the new coronavirus, and most of the particles in the exhaled breath are smaller than PM2.5 (particles with a particle size less than 2.5 microns), which further reveals the fact that aerosols spread the new coronavirus.
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