Clinical characteristics and outcome of patients with SARS-CoV-2 Omicron variant in Shanghai: A single center, retrospective, observational study oleh Da-Wei Yang, Jing Li, Li Feng, Hui-Fen Weng, Min-Jie Ju, Hao Wang, Yi-Chen Jia, Xiao-Dan Wang, Jia Fan, Zuo-Qin Yan, Xing-Wei Lu, Wei Yang, Yin Wu, Zheng-Guo Chen, Qi-Yun Jiang, Jian-Wei Xuan, Qiqing Shi, Hao Fang