• Peter G Kremsner, Philipp Mann, Arne Kroidl, Isabel Leroux-Roels, Christoph Schindler, Julian J Gabor, Mirjam Schunk, Geert Leroux-Roels, Jacobus J Bosch, Rolf Fendel, Andrea Kreidenweiss, Thirumalaisamy P Velavan, Mariola Fotin-Mleczek, Stefan O Mueller, Gianluca Quintini, Oliver Schönborn-Kellenberger, Dominik Vahrenhorst, Thomas Verstraeten, Margarida Alves de Mesquita, Lisa Walz, Olaf-Oliver Wolz, Lidia Oostvogels, and CV-NCOV-001 Study Group.
• Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany.
• Wien. Klin. Wochenschr. 2021 Sep 1; 133 (17-18): 931941931-941.

BackgroundWe used the RNActive® technology platform (CureVac N.V., Tübingen, Germany) to prepare CVnCoV, a COVID-19 vaccine containing sequence-optimized mRNA coding for a stabilized form of SARS-CoV‑2 spike (S) protein encapsulated in lipid nanoparticles (LNP).MethodsThis is an interim analysis of a dosage escalation phase 1 study in healthy 18-60-year-old volunteers in Hannover, Munich and Tübingen, Germany, and Ghent, Belgium. After giving 2 intramuscular doses of CVnCoV or placebo 28 days apart we assessed solicited local and systemic adverse events (AE) for 7 days and unsolicited AEs for 28 days after each vaccination. Immunogenicity was measured as enzyme-linked immunosorbent assay (ELISA) IgG antibodies to SARS-CoV‑2 S‑protein and receptor binding domain (RBD), and SARS-CoV‑2 neutralizing titers (MN50).ResultsIn 245 volunteers who received 2 CVnCoV vaccinations (2 μg, n = 47, 4 μg, n = 48, 6 μg, n = 46, 8 μg, n = 44, 12 μg, n = 28) or placebo (n = 32) there were no vaccine-related serious AEs. Dosage-dependent increases in frequency and severity of solicited systemic AEs, and to a lesser extent local AEs, were mainly mild or moderate and transient in duration. Dosage-dependent increases in IgG antibodies to S‑protein and RBD and MN50 were evident in all groups 2 weeks after the second dose when 100% (23/23) seroconverted to S‑protein or RBD, and 83% (19/23) seroconverted for MN50 in the 12 μg group. Responses to 12 μg were comparable to those observed in convalescent sera from known COVID-19 patients.ConclusionIn this study 2 CVnCoV doses were safe, with acceptable reactogenicity and 12 μg dosages elicited levels of immune responses that overlapped those observed in convalescent sera.© 2021. The Author(s).

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