Each of the five main past and present VoC escape neutralization by vaccine-elicited sera to varying degrees. NAb titers against Alpha are, on average, 2.75 times lower compared with those against Wuhan [106,119–122], those against Beta are 6.74-fold [106,109,112,119,120,122,123], those against Gamma are 3.43-fold [109,120,124], those against Delta are 3.76-fold [106,119–123], and those against Omicron are 56.50-fold lower [107,119,123,125]. Values are presented as mean fold change compared with Wuhan, error bars represent the range of the referenced studies. Total number of serum samples from pooled publications indicated. NAb, neutralizing antibodies; RBD, receptor-binding domain; VoC, variants of concern.