6 neutra a n assay was used to measure neutralization. The pseudoviruses tested incorporated D614G or the spike substitutions present in B.1.1.7 (Alpha), B.1.1.7 + E484K, B.1.427/B.1.429, P.1 (Gamma), B.1.351-v1 (Beta), B.1.351-v2 (Beta), B.1.351-v3 (Beta), B.1.526, B.1.617.1-v1, B.1.617.1-v2, B.1.617.2 (Delta), A.23.1-v1, A.23.1-v2, B.1.525, and A.VOI.V2 (Table 1). The reciprocal neutralizing titers on the pseudovirus neutralization assay at a 50% inhibitory dilution