美去年12月或已有新冠
COVID-19 likely in US in Dec 2019 COVID-19 infections were present in the US as early as mid-December 2019, weeks before it was first identified in China and about a month earlier than the first case was officially confirmed in the US, according to a new study by the US Centers for Disease Control and Prevention (CDC). In the study published in the journal Clinical Infectious Diseases, CDC researchers tested blood samples from 7,389 routine blood donations collected by the American Red Cross from Dec 13, 2019, to Jan 17, 2020, for antibodies specific to the novel coronavirus, known as SARS-CoV-2. The researchers found evidence of infection in 106 of the 7,389 blood donations from residents in nine states. The findings suggest that SARS-CoV-2 infections may have been present in the US in mid-December 2019, earlier than the first identified case in the US on Jan 19 this year. |