A case of coronavirus disease 2019 with twice negative nucleic acid testing within 8 days

To the Editor:To date,coronavirus disease 2019(COVID-19)has spread all over the world.As the exact sources of the virus,the time of virus shedding after infection and viral propagation are still undefined,there are still great challenges in controlling the virus spreading and the treatment of infection.Rapid diagnosis of infection cases and early isolation are extremely important for the overall prevention and control work.[1]Therefore,rapid diagnosis of infection cases and early isolation are extremely important for overall disease prevention and control.[2]