Alliance for Pandemic Preparedness

February 18, 2021

Circulating SARS-CoV-2 Variants Escape Neutralization by Vaccine-Induced Humoral Immunity

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[Pre-print, not peer reviewed] Analysis of neutralizing activity of sera from individuals vaccinated with either 1 or 2 doses of the Moderna or Pfizer vaccines (n=48) against SARS-CoV-2 pseudoviruses bearing spike proteins with the partial or full set of mutations from the B.1.351 variant show up to a 97-fold decrease in neutralization compared to wild-type.  Notably, neutralization of B.1351 was not detectable in samples from 36% (8/22) recipients of 2-dose Pfizer vaccine and 50% (2/4) recipients of 2-dose Moderna vaccine. In contrast, other variants such as the D614G variant, the B.1.1.7 variant, and variants from the P.1 lineage had relatively lower reductions in neutralization.

Assays conducted with sera from 22 of the 2-dose Pfizer vaccine recipients show that neutralization of B.1.351 in the absence of the mutations present in the receptor binding domain (RBD) was comparable to that of D614G, suggesting that the RBD mutations of the B.1.351 variant are key to neutralization resistance.

Garcia-Beltran et al. (Feb 18, 2021). Circulating SARS-CoV-2 Variants Escape Neutralization by Vaccine-Induced Humoral Immunity. Pre-print downloaded Feb 18 from https://doi.org/10.1101/2021.02.14.21251704