www.fox6now.comCoronavirus was present in US earlier than initially thought: StudyA recent study found traces of the virus in blood donations collected starting in December of last year. 根据周一发布的一项政府研究,2019年12月中旬美国就有人感染了新冠病毒,比中国正式确定该病毒早了几周,比公共卫生部门发现美国首例病例早了大约一个月。