An mRNA vaccine encoding the SARS-CoV-2 receptor-binding domain protects mice from various Omicron variants.

"Competing interests N.J., K.M., and F.T. are employees of Daiichi Sankyo Co., Ltd. Y.K. is a co-founder of FluGen and has received unrelated funding support from Daiichi Sankyo Co., Ltd., Fujifilm Toyama Chemical Co., Ltd., Tauns Laboratories, Inc., Shionogi & Co. Ltd., Otsuka Pharmaceutical Co., Ltd., KM Biologics Co. Ltd., Kyoritsu Seiyaku Corporation, Shinya Corporation, and Fuji Rebio, Inc.. The remaining authors declare that they have no competing interests."

"We thank Susan Watson for scientific editing. We also thank Michiko Ujie, Naoko Mizutani, Madoka Yoshikawa, Rie Onoue, Kyoko Yokota, Kyoko Tada, Kengo Kajiyama, and Mao Suzuki for technical assistance. Vero E6-TMPRSS2-T2A-ACE2 cells were provided by Dr. Barney Graham, NIAID Vaccine Research Center. This study was supported by grants from the Japan Program for Infectious Diseases Research and Infrastructure (JP23wm0125002), the Japan Initiative for World-leading Vaccine Research and Development Centers (JP233fa627001), and the Vaccine Development project (JP21nf0101625) from the Japan Agency for Medical Research and Development."