Author Correction: An RBD-Fc mucosal vaccine provides variant-proof protection against SARS-CoV-2 in mice and hamsters - Yanjun Zhang; Yan Wu; Meng-Qian Zhang; Haiyue Rao; Zhaoyong Zhang; Xiangyue He; Yiwen Liang; Raoqing Guo; Yaochang Yuan; Jing Sun; Helen M. E. Duyvesteyn; Elizabeth E. Fry; et al. (npj Vaccines)