Serum cytokine concentration by dose and trial visit. IFNα (a), IFNy (b), IP-10 (c), CXCL11 (d), MCP-1 (e), and IL-10 (f) serum concentrations on Days 1, 2, 8, 29, 30, and 36 in SARS-CoV-2 seronegative participants vaccinated with two doses of 2, 12, or 20 µg of CVnCoV. If participants did not receive a second CVnCoV dose, their Day 30 and 36 values were excluded from analysis. Bars show median values with interquartile ranges. Dotted lines indicate the lower level of quantification (LLOQ) and values below LLOQ were reported as extrapolated values. Values below the detection limit were set to the lowest extrapolated value reported for the respective cytokine. Statistical comparisons in one dose group (indicated as *) were analyzed using a two-tailed Wilcoxon signed-rank test and comparisons of the Day 2 and Day 30 timepoints between dose groups were analyzed using a Kruskal–Wallis ANOVA with Dunn’s multiple comparisons testing, with 2 µg as the reference (indicated as #). Significance defined as */# p ≤ 0.05, **/## p ≤ 0.01, ***/### p ≤ 0.001, or #### p ≤ 0.0001. CXCL, chemokine (C-X-C motif) ligand 1; IFNα, interferon alpha; IFNy, interferon gamma; IL-10, interleukin 10; IP-10, interferon-gamma inducible protein 10 kDa; MCP-1, membrane cofactor protein 1.