Figure 2.

Divergence between the binding and neutralization potential of human sera against SARS-CoV-2 Mu and Gamma. (A) Anti-RBD antibody titers against the Wuhan ancestral strain, as well as Gamma, Mu, and Delta variants, in naturally-infected individuals (n=50, both mild and severe disease) at 1-month PSO between June and December 2020 (period of low/absent circulation of Gamma and Mu). (B) Anti-RBD antibody titers against the Wuhan ancestral strain, as well as Gamma, Mu, and Delta variants in samples from 29 individuals (Los Andes cohort) who were seronegative up to December 2020 and seroconverted 6 months later in May 2021, during an active circulation of Gamma and Mu variants. Each circle represents an individual sample. The height of the bars and the numbers over them indicate the geometric mean titer. The 95% CI is also shown. The Friedman test was performed. ns, Not statistically significant. (C) Neutralization of infectious SARS-CoV-2 by human sera was determined by Focus Neutralization Reduction Test (FRNT). FRNT₅₀ values for SARS-CoV-2 Gamma and Mu were determined by non-linear regression analysis for SARS-CoV-2 naturally-infected subjects (samples at 1-month PSO). Each circle represents an individual sample. The bars indicate the geometric mean. The Wilcoxon test was performed. The dotted lines represent the limit of detection of the assays. *p-value <0.05; **p-value <0.01; ***p-value <0.001; ****p-value <0.0001.