Fig. 3.

SARS-CoV-2 B cell response evolution in vaccinated individuals naive to infection or previously infected. A The three samples collected per participant were placed in a timeline according to their distance in days from the second dose of vaccination. After vaccination, anti-Spike (SP) IgG antibodies rapidly declined after 3 months in participants naive to infection (n = 212, p < 0.0001, Spearman r =  − 0.62). In vaccinated and previously infected participants (n = 68), anti-SP IgG levels significantly increased after vaccination and were more stable over time (p = 0.018, Spearman r =  − 0.22). B The neutralization capacity of anti-SP IgG was strongly correlated to the antibody levels in both vaccinated and naive to infection and vaccinated and previously infected (p < 0.0001, Spearman r = 0.9; p < 0.0001, Spearman r = 0.86, respectively). C In previously infected individuals, the neutralization capacity of anti-SP IgG antibodies significantly increased after vaccination (p < 0.0001). D Neutralization for the Alpha and Delta variants was compared in percentage to the Wuhan variant. Both groups had a stronger neutralization capacity to the original Wuhan variant than for the Alpha and Delta variants. There was no difference in the neutralization between the Alpha and Delta variants in vaccinated and previously infected individuals. *p < 0.05, **p < 0.005, ***p < 0.0005, ****p < 0.00005