Fig. 1: Analysis for neutralization of variant SARS-CoV-2 by serum samples from the V-01 phase II trial participants and the V-01-vaccinated animals.

a Serum samples (n = 20) were collected from participants in the V-01 vaccine phase II trial on day 49 (28 days post the second dose) immunized with two doses of 10 μg of V-01. Samples were tested for neutralizing activity against WT SARS-CoV-2, B.1.1.7, B.1.351, and B.1.617.2 variants, using pseudovirus neutralization assays. The geometric mean of neutralizing antibody titer (GMT) is shown at the top of the indicated column, and 95% confidence intervals are shown. The GMT fold-reduction over the WT for each variant is indicated. b C57BL/6 mice (n = 10/group) were intramuscularly vaccinated three times with 2 μg of V-01 on days 0, 14, 28, or immunized twice with 2 μg of V-01 and further boosted with the equivalent dose of Beta-V-01 or Delta-V-01 on day 28 after prime immunization, respectively. The serum samples were collected on day 42 after initial vaccination to evaluate the neutralizing antibody titers. The pVNT₅₀ in serum sample against wild-type SARS-CoV-2, B.1.315, B.1.617.2, and B.1.1.7 variants were analyzed using pseudovirus neutralization assays. c Rhesus macaques were intramuscularly immunized with V-01 via a prime-boost vaccination regimen at a 14-day interval. These macaques were then given a booster dose of V-01 after 300 days of initial vaccination. The serum samples were collected on day 300 post the initial immunization and 21 days after the third dose and subjected to pseudovirus neutralization assays. The pVNT₅₀ of these sera against WT SARS-CoV-2 and the variants B.1.1.7, B.1.351, B.1.67.2, and B.1.67.1 was analyzed. The GMT fold changes after the third dose vs before the third dose are labeled. Data are shown as GMT and 95% confidence intervals. P values were calculated by one-way ANOVA with multiple comparison tests. n.s., not significant, *P < 0.05, **P < 0.01.