Fig. 1: SARS-CoV-2 humoral, cellular and anti-vector response elicited by GRAd-COV2 vaccination over time.

SARS-CoV-2 humoral, cellular and anti-vector response induced by GRAd-COV2 vaccination and measured at the day of vaccination (w0) and 1, 2, 4, 8, 12 and 24 weeks (w1, w2, w4, w8, w12, w24 respectively) after vaccination over 6 months follow up. N = 15 for each study arm. a IgG binding to S1-S2 measured by CLIA. Data are expressed as arbitrary unit (AU)/ml. b SARS-CoV-2 specific IgG measured by ELISA on recombinant full-length spike protein. c SARS-CoV-2 specific IgG measured by ELISA on RBD. Data in both b and c are expressed as binding antibody units (BAU)/ml. d Neutralizing activity detected by SARS-CoV-2 microneutralization assay. e Neutralizing activity detected by Spike (D614G)-pseudotyped lentivirus neutralization assay. SARS-CoV-2 neutralization titers are expressed as MNA₉₀, or the reciprocal of serum dilution achieving 90% neutralization, or in International Units (IU)ml, in d and e respectively. f Spike-specific T cell response measured by IFNγ ELISpot on frozen PBMC. Data are expressed as IFNγ spot forming cells (SFC) per 10⁶ PBMC. g Neutralizing titers to the GRAd vector, measured by a neutralization assay based on SEAP reporter gene activity inhibition. Throughout, blue and red color shades identify younger (Y-circles) and older age (O-triangles) cohorts, respectively, and color tone increase with vaccine dose: low dose (LD, 5 × 10¹⁰ vp), intermediate dose (ID, 1 × 10¹¹ vp) and high dose (HD, 2 × 10¹¹ vp). Square symbols indicate human convalescent serum obtained from either previously hospitalized (hosp-dark gray) or from non-hospitalized (non-hosp-light gray) COVID-19 patients. NIBSC 20/130 research reagent plasma (red diamond) is shown for reference (panels b to c). Data are shown either as the group geometric mean and 95% confidence interval (CI) (panels a, b, c, f and g) or as individual points and box and whiskers indicating median and interquartile range, with whiskers ranging from min to max (panels d and e). Negative samples were assigned a value of ½ the LOD.