Fig. 4. ACE2 displacement activities against the original and Delta SARS-CoV-2 variants after one and two doses of COVID-19 vaccine.

a ACE2 displacement activities of plasma antibodies against the original wild-type (wt) and Delta variant Spike-RBD in naive PLWH, naive controls, and convalescent individuals one month after the first vaccine dose. Horizontal red lines depict the median, 1st and 3rd quartiles. p-values were computed using the Wilcoxon matched-pairs signed rank test and are uncorrected for multiple comparisons. b Responses one month after the second vaccine dose, displayed as in (a). c Responses 3 months after the second vaccine dose, displayed as in (a).