Optimization of non-coding regions for a non-modified mRNA COVID-19 vaccine

Makda S. Gebre, Susanne Rauch, Nicole Roth, Jingyou Yu, Abishek Chandrashekar, Noe B. Mercado, Xuan He, Jinyan Liu, Katherine McMahan, Amanda Martinot, David R. Martinez, Victoria Giffin, David Hope, Shivani Patel, Daniel Sellers, Owen Sanborn, Julia Barrett, Xiaowen Liu, Andrew C. Cole, Laurent PessaintDaniel Valentin, Zack Flinchbaugh, Jake Yalley-Ogunro, Jeanne Muench, Renita Brown, Anthony Cook, Elyse Teow, Hanne Andersen, Mark G. Lewis, Adrianus C.M. Boon, Ralph S. Baric, Stefan O. Mueller, Benjamin Petsch, Dan H. Barouch

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


The CVnCoV (CureVac) mRNA vaccine for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was recently evaluated in a phase 2b/3 efficacy trial in humans1. CV2CoV is a second-generation mRNA vaccine containing non-modified nucleosides but with optimized non-coding regions and enhanced antigen expression. Here we report the results of a head-to-head comparison of the immunogenicity and protective efficacy of CVnCoV and CV2CoV in non-human primates. We immunized 18 cynomolgus macaques with two doses of 12 μg lipid nanoparticle-formulated CVnCoV or CV2CoV or with sham (n = 6 per group). Compared with CVnCoV, CV2CoV induced substantially higher titres of binding and neutralizing antibodies, memory B cell responses and T cell responses as well as more potent neutralizing antibody responses against SARS-CoV-2 variants, including the Delta variant. Moreover, CV2CoV was found to be comparably immunogenic to the BNT162b2 (Pfizer) vaccine in macaques. Although CVnCoV provided partial protection against SARS-CoV-2 challenge, CV2CoV afforded more robust protection with markedly lower viral loads in the upper and lower respiratory tracts. Binding and neutralizing antibody titres were correlated with protective efficacy. These data demonstrate that optimization of non-coding regions can greatly improve the immunogenicity and protective efficacy of a non-modified mRNA SARS-CoV-2 vaccine in non-human primates.

Original languageEnglish
Pages (from-to)410-414
Number of pages5
Issue number7893
StatePublished - Jan 20 2022


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