Real-time PCR detection of SARS-CoV-2
Over 240 swab samples were obtained from the upper respiratory tracts of participants at different time points throughout hospitalization. The presence of SARS-CoV-2 was detected by qRT-PCR assay as previously reported. Briefly, the nucleocapsid protein and open reading frame 1ab were amplified and examined with two pairs of primers. Each sample was detected in triplicate with positive and negative controls. The diagnostic criteria were based on the recommendations by the National Centers for Disease Control and Prevention of China.