The serum flow profile of pneumonia in COVID-19 shows that the population in China is generally at a low infection level in SARS-CoV-2. 据新华社报道, Beijing, 十二月 29 (Reporter Tian Xiaohang Mu Tiecheng), the reporter learned from the Chinese Center for Disease Control and Prevention that one month after China curbed the first wave of COVID-19 pneumonia, …