%0 Journal Article %A Tamarand L. Darling %A Baoling Ying %A Bradley Whitener %A Laura A. VanBlargan %A Traci L. Bricker %A Chieh-Yu Liang %A Astha Joshi %A Gayan Bamunuarachchi %A Kuljeet Seehra %A Aaron J. Schmitz %A Peter J. Halfmann %A Yoshihiro Kawoaka %A Sayda M. Elbashir %A Darin K. Edwards %A Larissa B. Thackray %A Michael S. Diamond %A Adrianus C. M. Boon %T mRNA-1273 and Ad26.COV2.S vaccines protect against the B.1.621 variant of SARS-CoV-2 %D 2021 %R 10.1101/2021.12.29.474432 %J bioRxiv %P 2021.12.29.474432 %X Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019, viral variants with greater transmissibility or immune evasion properties have arisen, which could jeopardize recently deployed vaccine and antibody-based countermeasures. Here, we evaluated in mice and hamsters the efficacy of preclinical non-GMP Moderna mRNA vaccine (mRNA-1273) and the Johnson & Johnson recombinant adenoviral-vectored vaccine (Ad26.COV2.S) against the B.1.621 (Mu) South American variant of SARS-CoV-2, which contains spike mutations T95I, Y144S, Y145N, R346K, E484K, N501Y, D614G, P681H, and D950N. Immunization of 129S2 and K18-human ACE2 transgenic mice with mRNA-1273 vaccine protected against weight loss, lung infection, and lung pathology after challenge with B.1.621 or WA1/2020 N501Y/D614G SARS-CoV-2 strain. Similarly, immunization of 129S2 mice and Syrian hamsters with a high dose of Ad26.COV2.S reduced lung infection after B.1.621 virus challenge. Thus, immunity induced by mRNA-1273 or Ad26.COV2.S vaccines can protect against the B.1.621 variant of SARS-CoV-2 in multiple animal models.Competing Interest StatementThe Boon laboratory has received unrelated funding support in sponsored research agreements from AI Therapeutics, GreenLight Biosciences Inc., and Nano targeting & Therapy Biopharma Inc. The Boon laboratory has received funding support from AbbVie Inc., for the commercial development of SARS-CoV-2 mAb. M.S.D. is a consultant for Inbios, Vir Biotechnology, Senda Biosciences, and Carnival Corporation, and on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory has received unrelated funding support in sponsored research agreements from Vir Biotechnology, Kaleido, and Emergent BioSolutions and past support from Moderna not related to these studies. S.E. and D.K.E. are employees of and shareholders in Moderna Inc. %U https://www.biorxiv.org/content/biorxiv/early/2021/12/29/2021.12.29.474432.full.pdf