Figure 3.

Neutralization of SARS-CoV-2 infectivity by plasma, according to subject infection and BNT162b2 vaccination history. Three viral variants (B.1 wild type-like early strain, Gamma, and Delta) were pre-incubated with serial dilutions of subject plasma before evaluating their infectivity of Vero E6 cells (ATCC #CRL-1586; African green monkey kidney epithelium). Y-axes denote plasma neutralization titers. All three experimental groups displayed variably increasing neutralization activity against the three SARS-CoV-2 variants, with timing of maximal observed neutralization approximating that when maximum anti-RBD and anti-S1 IgG levels were measured (detailed in Figure 1 ). The highest mean neutralization titers (and anti-RBD and anti-S1 IgG levels) were observed in individuals who received a single vaccine dose after recovering from Covid-19.