Corrigendum: Identifying risk factors for secondary infection post-SARS-COV-2 infection in patients with severe and critical COVID-19 - Mingquan Guo; Mingquan Guo; Menglu Gao; Jing Gao; Tengfei Zhang; Xin Jin; Jian Fan; Qianying Wang; Xin Li; Jian Chen; Zhaoqin Zhu (Frontiers in Immunology)