Circulating SARS-CoV-2 variants escape neutralization by vaccine-induced humoral immunity.

Vaccination elicits immune responses capable of potently neutralizing SARS-CoV-2. However, ongoing surveillance has revealed the emergence of variants harboring mutations in spike, the main target of neutralizing antibodies. To understand the impact of globally circulating variants, we evaluated the neutralization potency of 48 sera from BNT162b2 and mRNA-1273 vaccine recipients against pseudoviruses bearing spike proteins derived from 10 strains of SARS-CoV-2. While multiple strains exhibited vaccine-induced cross-neutralization comparable to wild-type pseudovirus, 5 strains harboring receptor-binding domain mutations, including K417N/T, E484K, and N501Y, were highly resistant to neutralization. Cross-neutralization of B.1.351 variants was weak and comparable to SARS-CoV and bat-derived WIV1-CoV, suggesting that a relatively small number of mutations can mediate potent escape from vaccine responses. While the clinical impact of neutralization resistance remains uncertain, these results highlight the potential for variants to escape from neutralizing humoral immunity and emphasize the need to develop broadly protective interventions against the evolving pandemic.