GPT and COVID-19: In addition, the marked increases in the circulating levels of alanine aminotransferase (ALT) and AST in COVID-19 patients compared with healthy volunteers observed in our study (Supplementary Tables 1–2 and Supplementary Fig. 3a, b) and the hepatocellular injury observed in patients with COVID-19 by others suggested that SARS-CoV-2 attacks hepatocytes as target cells.22 Therefore, Huh7 cells were selected for the subsequent experiments in this study.