摘要
Dear Editor,Coronavirus Disease 2019(COVID-19)outbreak caused by sever acute respiratory syndrome coronavirus 2(SARSCo V-2)presents a global pandemic which has resulted in more than 4 million people death in the world.In China,the initial transmission of COVID-19 has already been blocked by strict control strategies and effective treatment for patients.All local COVID-19 outbreaks after April2020 were related to overseas importing.Up to February2021,207 imported COVID-19 cases have been reported in Tianjin,China(Tianjin Health Commission,2021).
基金
supported by Tianjin Municipal Commission of Health COVID-19 Prevention and Control Technology General Project(No.2020xkm01 and No.2020xkz01)
Science and Technology Program of Tianjin,China(No.20JCZDJC00130)。
