Dynamic changes of serum SARS-CoV-2 antibody levels in COVID-19 patients. Issue 1 (July 2022) - He, Lu; Xu, Wanzhou; Zeng, Cheng; Li, Ying; Lin, Ren; Xie, Xiaojie; Xia, Hongmiao; Tang, Shiqi; Xu, Lijuan; Chen, Changzheng